Planar light source and method for manufacturing the same

Abstract

The present invention provides a planar light source and a manufacturing method thereof, which can suppress the light emitted by the light source from being absorbed by a wiring material. The planar light source mainly comprises: a light source (20) having a pair of positive and negative electrodes (21) on one side; a light guide component (10) covering the light source (20) in a manner that exposes the electrodes (21); a wiring substrate (30) having a wiring layer (32) electrically connected to the electrodes (21); and a light reflecting sheet (40) sandwiched between the light guide component (10) and the wiring substrate (30). The light reflecting sheet (40) has first through holes (41) corresponding to each of the positive and negative electrodes (21) in a pair, and the electrodes (21) and the wiring layer (32) are electrically connected by a conductive component (50) arranged via the first through holes (41).

Description

Technical Field

[0001] The present disclosure relates to a planar light source and a method for manufacturing the same. Background Art

[0002] Planar light sources using light-emitting diodes as light sources are used in many devices such as backlights of liquid crystal televisions. In order to achieve high brightness and low power consumption of such planar light sources, it is necessary to effectively utilize the light from the light source. For example, Patent Document 1 discloses a technology for improving light extraction efficiency in a light-emitting device in which wiring is exposed and light-emitting elements are connected.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-003994 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The technical problem of the present disclosure is to provide a planar light source and a method for manufacturing the planar light source that suppresses light from the light source from being absorbed by a wiring material.

[0008] Means for solving technical problems

[0009] The planar light source disclosed in the present invention comprises: a light source having a pair of positive and negative electrodes on one side; a light-guiding component covering the light source in a manner that exposes the electrodes; a wiring substrate having a wiring layer electrically connected to the electrodes; a light-reflecting sheet sandwiched between the light-guiding component and the wiring substrate, having first through holes corresponding to each of the positive and negative electrodes in a pair; the electrodes and the wiring layer are electrically connected using a conductive component configured via the first through holes.

[0010] The manufacturing method of the planar light source disclosed in the present invention includes: a light-emitting module preparation step, preparing a light-emitting module, the light-emitting module comprising a light source, a light-guiding component and a first light-reflecting sheet, the light source having a pair of positive and negative electrodes on one side, the light-guiding component covering the light source in a manner to expose the electrodes, the first light-reflecting sheet having first through holes corresponding to each of the positive and negative electrodes in a pair; a wiring substrate preparation step, preparing a wiring substrate having a wiring layer electrically connected to the electrodes; a light-emitting module bonding step, bonding the light-emitting module to the wiring substrate; and a connection step, electrically connecting the electrodes to the wiring layer via a conductive component arranged in the first through hole.

[0011] In addition, the manufacturing method of the planar light source disclosed in the present invention includes: a wiring substrate preparation step, wherein a first light reflecting sheet having a first through hole is arranged on a wiring substrate having a wiring layer in a manner such that the wiring layer is opposite to the first through hole, the wiring layer is electrically connected to the electrode of a light source having a pair of positive and negative electrodes on one side, and the first through hole is opposite to each of the positive and negative electrodes one by one; a light-emitting module preparation step, wherein a light-emitting module including the light source, a second light reflecting sheet and a light-guiding component is prepared, the second light reflecting sheet having a second through hole opposite to the first through hole and in which the light source is arranged, the light-guiding component covers the light source in a manner such that the electrode is exposed, the light source is arranged in the second through hole, and the light source is arranged on the light-guiding component; a light-emitting module bonding step, wherein the first light reflecting sheet is clamped in a manner such that the electrode is opposite to the first through hole, and the light-emitting module is bonded to the wiring substrate; a connection step, wherein the electrode is electrically connected to the wiring layer via a conductive component arranged in the first through hole.

[0012] Effects of the Invention

[0013] According to the present disclosure, it is possible to realize a planar light source and a method for manufacturing the planar light source that can suppress absorption of light by wiring materials and more effectively utilize light emitted by the light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic perspective view showing the planar light source according to the first embodiment.

[0015] Figure 2 yes Figure 1 A schematic cross-sectional view taken along line II-II is shown.

[0016] Figure 3A This is a schematic perspective view showing an example of the light source according to the first embodiment.

[0017] Figure 3B yes Figure 3A A schematic cross-sectional view taken along line IIIB-IIIB is shown.

[0018] Figure 3C Yes means Figure 3A A schematic bottom view of the side of the light source with the electrodes is shown.

[0019] Figure 4 This is a schematic plan view showing an opening portion of a cover layer in the wiring substrate according to the first embodiment.

[0020] Figure 5 It is a schematic perspective view showing the light emitting module according to the first embodiment.

[0021] Figure 6It is a schematic plan view showing the positional relationship between the light source and the light reflecting member according to the first embodiment.

[0022] Fig. 7A This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0023] Figure 7B This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0024] Figure 7C This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0025] Fig.7D This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0026] Fig. 7E This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0027] Figure 7F This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0028] Fig. 8A This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0029] Figure 8B This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0030] Fig.9A This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0031] Fig. 9B This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0032] Fig. 9C This is a schematic cross-sectional view showing an example of the manufacturing method of the first embodiment.

[0033] Fig.10 It is a schematic cross-sectional view showing a part of the planar light source according to the second embodiment.

[0034] Fig.11A This is a schematic cross-sectional view showing an example of the manufacturing method according to the second embodiment.

[0035] Fig. 11B This is a schematic cross-sectional view showing an example of the manufacturing method according to the second embodiment.

[0036] Fig. 12AThis is a schematic cross-sectional view showing an example of the manufacturing method according to the second embodiment.

[0037] Fig. 12B This is a schematic cross-sectional view showing an example of the manufacturing method according to the second embodiment.

[0038] Fig.13 It is a schematic cross-sectional view showing a part of the planar light source according to the third embodiment.

[0039] Fig.14 It is a schematic perspective view showing a light emitting module according to a third embodiment.

[0040] Fig.15A This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0041] Fig. 15B This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0042] Fig. 15C This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0043] Fig.15D This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0044] Fig.15E This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0045] Fig.15F This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0046] Figure 15G This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0047] Fig.15H This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0048] Fig.16A This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0049] Fig. 16B This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0050] Fig. 16C This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0051] Fig.17A This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0052] Fig. 17B This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0053] Fig. 17C This is a schematic cross-sectional view showing an example of the manufacturing method according to the third embodiment.

[0054] Fig.18A It is a schematic cross-sectional view showing a modified example of the light source.

[0055] Fig.18B It is a schematic cross-sectional view showing a modified example of the light source.

[0056] Fig.18C It is a schematic cross-sectional view showing a modified example of the light source.

[0057] Fig.18D It is a schematic cross-sectional view showing a modified example of the light source.

[0058] Fig.19A It is a schematic perspective view showing a modified example of the light guide member.

[0059] Fig.19B It is a schematic cross-sectional view showing a modified example of the light guide member.

[0060] Fig.19C It is a schematic cross-sectional view showing a modified example of the light guide member.

[0061] Fig. 20A This is a schematic cross-sectional view showing an example of a method for manufacturing a modified example of a light guide member.

[0062] Fig. 20B This is a schematic cross-sectional view showing an example of a method for manufacturing a modified example of a light guide member.

[0063] Fig. 20C This is a schematic cross-sectional view showing an example of a method for manufacturing a modified example of a light guide member.

[0064] Fig.20D This is a schematic cross-sectional view showing an example of a method for manufacturing a modified example of a light guide member.

[0065] Fig.20E This is a schematic cross-sectional view showing an example of a method for manufacturing a modified example of a light guide member.

[0066] Fig.20F This is a schematic cross-sectional view showing an example of a method for manufacturing a modified example of a light guide member.

[0067] Fig.21 It is a schematic cross-sectional view showing a planar light source including a wiring substrate according to a modification of the present embodiment.

[0068] Fig. 22 This is a flowchart showing the method for manufacturing the planar light source according to the present embodiment.

[0069] Description of Reference Numerals

[0070] 10 Light guide components

[0071] 11 Light source arrangement portion of light guide component

[0072] 15a Light guide plate

[0073] 20 Light Source

[0074] 21 A pair of positive and negative electrodes of the light source

[0075] 22 Light source light emitting element

[0076] 23 Translucent components of light source

[0077] 24A Light adjustment member of light source (first light adjustment member)

[0078] 25 The area between the electrodes on the surface of the light source having electrodes

[0079] 26 Covering parts of light source

[0080] 30 Wiring substrate

[0081] 31 Third through hole

[0082] 32 Wiring layer of wiring substrate

[0083] 34 Insulating base material of wiring board

[0084] 36 Covering layer of wiring substrate

[0085] 40 light reflecting sheet, first light reflecting sheet

[0086] 41 First through hole

[0087] 45 Second light reflector

[0088] 46 Second through hole

[0089] 50 Conductive parts

[0090] 51 first conductive component

[0091] 52 second conductive component

[0092] 60 light adjustment member (second light adjustment member)

[0093] 70 Light reflecting parts

[0094] 75 Modification of light reflecting member

[0095] 80 Protective components

[0096] 90 Bonding substrate

[0097] 100 Light emitting modules

[0098] 150 light emitting module assembly

[0099] Part of 200A surface light source

[0100] 200, 300 Surface light source DETAILED DESCRIPTION

[0101] Hereinafter, the surface light source and the manufacturing method thereof of the embodiment will be described with reference to the accompanying drawings. Note that the drawings referred to in the following description of the embodiment are used to schematically represent the embodiment, so the size, spacing or positional relationship of each component may be exaggerated, part of the component illustration may be omitted, or an end view showing only the cross-section surface may be used as a cross-sectional view. In addition, in the following description, the same names and figure numbers, in principle, represent the same or homogeneous components, and the detailed description is appropriately omitted. In this specification, "upper", "lower", etc., in the drawings referred to for explanation, represent the relative positions between the constituent elements, and are not intended to represent absolute positions unless otherwise specified.

[0102] [First embodiment]

[0103] <Surface light source>

[0104] Reference Figure 1 to Figure 4 An example of the structure of the planar light sources 200 and 300 according to the first embodiment will be described. Figure 2 The planar light source 200 shown in cross section has a structure corresponding to a portion 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, but have the same structure for one light emitting module.

[0105] The planar light source 300 mainly 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 in a manner that the electrodes 21 are exposed; a wiring substrate 30 having a wiring layer 32 electrically connected to the electrodes 21; and a light reflecting sheet 40 sandwiched between the light guide member 10 and the wiring substrate 30. For each of the positive and negative electrodes 21 of the light source 20, the light reflecting sheet 40 has a first through hole 41 facing the electrode 21 one by one, that is, for each electrode 21, the light reflecting sheet 40 has a first through hole 41 facing the electrode 21, and the electrode 21 and the wiring layer 32 are electrically connected by a conductive member 50 arranged via the first through hole 41.

[0106] The following describes the various structures of the planar light source 300. Note that 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 to the light reflecting sheet 40. Note that in this embodiment, a light adjustment member 60 is arranged on the upper surface of the light guide member 10.

[0107] <Light Source>

[0108] like Figure 2 to Figure 3C As shown, the light source 20 has a pair of positive and negative electrodes 21 on one side, and the light source 20 emits light when a voltage is applied from the outside via the electrodes 21. Figure 3A to Figure 3C As shown, the light source 20 includes a light emitting element 22, a light transmissive member 23A and a first light adjusting member 24A. The light source 20 is approximately rectangular and includes a pair of positive and negative electrodes 21 exposed on the lower surface of the light transmissive member 23A opposite to the upper surface on which the first light adjusting member 24A is disposed.

[0109] The light emitting element 22 includes a semiconductor stack. In this embodiment, the light emitting element 22 is surrounded by a light-transmitting member 23A at least on the upper surface and the side surface of the semiconductor stack. The semiconductor stack is configured to emit visible light or ultraviolet light, and any composition can be used according to the desired peak wavelength of light emission. For example, a nitride semiconductor (In x Al y Ga 1－x－y N, 0≤X, 0≤Y, X+Y≤1), GaP, or GaAlAs, AlInGaP, etc. that can emit red light. In addition, the size and number of the light emitting elements 22 can be appropriately selected according to the intended use.

[0110] The semiconductor stack 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 double heterojunction or single quantum well (SQW) structure or a structure including a single active layer group such as a multiple quantum well (MQW) structure.

[0111] In addition, the semiconductor stack may have a structure including more than one light-emitting layer between the n-type semiconductor layer and the p-type semiconductor layer, or may have a structure in which a structure including an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer is repeated multiple times in sequence. In the case where the semiconductor stack includes multiple light-emitting layers, it may include light-emitting layers with different peak emission wavelengths, or it may include light-emitting layers with the same peak emission wavelength. Note that the so-called same peak emission wavelength also includes the case where there is a deviation of about several nm. The combination of peak emission wavelengths between multiple light-emitting layers can be appropriately selected. For example, in the case where the semiconductor stack includes two light-emitting layers, the light-emitting layer can be selected according to a combination of 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 green light and red light. Each light-emitting layer may include multiple active layers with different peak emission wavelengths, or multiple active layers with the same peak emission wavelength.

[0112] The light-transmitting member 23A is made of, for example, a light-transmitting resin material, such as epoxy resin, silicone resin, or a resin obtained by mixing these. The light-transmitting member 23A may also include a phosphor, for example, by including a phosphor that absorbs blue light from the light-emitting element 22 and radiates yellow light, white light can be emitted from the light source 20. In addition, the light-transmitting member 23A may also include multiple types of phosphors, for example, by including a phosphor that absorbs blue light from the light-emitting element 22 and radiates yellow light and a phosphor that radiates red light, white light can also be emitted from the light source 20. As such a phosphor, for example, a yttrium-aluminum-garnet type phosphor (for example, Y3(Al, Ga)5O 12 :Ce), lutetium aluminum garnet phosphors (such as Lu3(Al, Ga)5O 12 :Ce), terbium aluminum garnet phosphors (such as Tb3(Al, Ga)5O 12 :Ce), CCA type phosphors (such as Ca10(PO4)6C 12 :Eu), SAE type phosphors (such as Sr4Al 14 O 25 :Eu), alkaline earth chlorosilicate phosphors (such as Ca8MgSi4O 16 C 12 :Eu), β-sialon phosphors (such as (Si,Al)3(O,N)4:Eu), α-sialon phosphors (such as Mz(Si,Al) 12 (O, N) 16:Eu (wherein 0<z≤2, M is Li, Mg, Ca, Y and lanthanum except La and Ce)), SLA type phosphors (for example SrLiA13N4:Eu), CASN type phosphors (for example CaAlSiN3:Eu) or SCASN type phosphors (for example (Sr, Ca)AlSiN3:Eu) and other nitride type phosphors, KSF type phosphors (for example K2SiF6:Mn), KSAF type phosphors (for example K2(Si, A1)F6:Mn) or MGF type phosphors (for example 3.5MgO·0.5MgF2·GeO2:Mn) and other fluoride type phosphors, phosphors with perovskite structure (for example CsPb(F, C1, Br, I)3) or quantum dot phosphors (for example CdSe, InP, AgInS2 or AgInSe2), etc.

[0113] In addition, a wavelength conversion plate containing the above-mentioned phosphor can also be arranged on the planar light source 200, 300. The wavelength conversion plate can absorb a part of the blue light from the light source 20 and emit yellow light, green light and / or red light to form a planar light source that emits white light. For example, a light source that can emit blue light can be combined with a wavelength conversion plate containing a phosphor that can emit yellow light to obtain white light. In addition, a light source that can emit blue light can also be combined with a wavelength conversion plate containing a red phosphor and a green phosphor. In addition, a light source that can emit blue light can also be combined with multiple wavelength conversion plates. As multiple wavelength conversion plates, for example, a wavelength conversion plate containing a phosphor that can emit red light and a wavelength conversion plate containing a phosphor that can emit green light can be selected. In addition, a light source having a light-emitting element that can emit blue light and a light-transmitting component that can emit red light can also be combined with a wavelength conversion plate containing a phosphor that can emit green light.

[0114] The first light adjustment member 24A is a member for adjusting the light distribution of the light source 20. The first light adjustment member 24A blocks or reflects a portion of the light emitted 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 by the first light adjustment member 24A so that the light emission directly above the light extraction surface of the planar light source 300 is not too strong and the light emission of the entire surface is uniform. When the transmittance of the first light adjustment member 24A to the light emitted from the light emitting element 22 is sufficiently low, for example, in the range of 1% to 50%, preferably in the range of 3% to 30%, the first light adjustment member 24A becomes a light shielding film, and it is possible to prevent the brightness directly above the light source 20 from being too high. As the first light adjustment member 24A, for example, a resin material containing a light diffusion material can be used, or a metal material can be used. For example, as the resin material, silicone resin, epoxy resin, or a resin obtained by mixing these can be used. In addition, as the light diffusion material, for example, a known material such as titanium oxide, silicon dioxide, aluminum oxide, zinc oxide, or glass can be used. In addition, the first light adjusting member 24A may be formed using a multilayer film (dielectric multilayer film) composed of a dielectric in which two or more dielectrics are stacked in plurality.

[0115] <Light guide components>

[0116] like Figure 1 , Figure 2 As shown, the light guide component 10 is a light-transmitting component for extracting the light from the light source 20 as planar light from the upper surface of the planar light source 300, which becomes the light extraction surface. The lower surface of the light guide component 10 is configured to be opposite to the light reflection sheet 40 except for the light source configuration portion 11 where the light source 20 is configured. In other words, the light reflection sheet 40 is completely opposite to the entire lower surface of the light guide component 10 and the entire lower surface of the light source 20, which can suppress the absorption of light by the wiring layer 32 and the like, and effectively utilize the light of the light source 20. The height of the light guide component 10 in the direction perpendicular to the light reflection sheet 40 is equal to or higher than the height of the light source 20, and can exceed the height of the light reflection component 70 described later. The height of such a light guide component 10 is preferably set to be about 200 μm or more and 800 μm or less, for example.

[0117] The light source 20 is disposed on the lower surface of the light guide member 10 so that the electrode 21 is exposed. The recessed portion of the light guide member 10 where the light source 20 is disposed is the light source placement portion 11. The light guide member 10 covers the upper surface and side surfaces of the light source 20 disposed in the light source placement portion 11.

[0118] As the material of the light guide member 10, for example, a resin material such as a thermoplastic resin such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate or polyester, a thermosetting resin such as epoxy resin or silicone resin, or a light-transmitting material such as glass can be used. In particular, polycarbonate is preferably used because it is highly transparent and inexpensive.

[0119] The upper surface of the light guide member 10 may have convex portions and / or concave portions in a low-brightness region, for example, in order to reduce uneven brightness.

[0120] <Light reflecting sheet>

[0121] The light reflecting sheet 40 is a sheet member that reflects light toward the light extraction surface of the planar light source 300. The light reflecting sheet 40 is interposed between the light guide member 10 and a wiring substrate 30 described later, and has one first through hole 41 facing one electrode 21.

[0122] As long as the opening of the first through hole 41 is large enough to include the entire electrode 21 inside when viewed from above, it is easy to make an electrical connection between the electrode 21 and the conductive component 50 described later. However, the larger the opening of the first through hole 41, the smaller the light reflecting sheet 40 at a position opposite to the light source 20. 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 becomes larger. Moreover, irradiating the wiring layer 32 and the like with light increases the chance of light being absorbed. Therefore, it is preferred to reduce the opening of the first through hole 41 in such a way that the shape of the opening of the first through hole 41 is roughly consistent with the shape of the electrode 21 when viewed from above, or in such a way that it is closer to the inside than the outer edge of the electrode 21. In addition, it is better that the opening of the first through hole 41 does not protrude outward from the outer edge of the light source 20 when viewed from above. In other words, the opening of the first through hole 41 is preferably closer to the inside than the outer edge of the light source 20 when viewed from above. As a result, it is possible to reduce the absorption of light from the light source 20 by the conductive component 50 arranged in the first through hole 41.

[0123] In order to effectively utilize light, the light reflecting sheet 40 preferably has a high reflectivity. The reflectivity of the light reflecting sheet 40 is preferably 90% or more, and more preferably 94% or more, at the wavelength of the light emitted by the light source 20.

[0124] The light reflecting sheet 40 may be made of a resin sheet containing a plurality of bubbles (e.g., a foamed resin sheet), a resin sheet containing a light diffusing material, or the like. As the resin used for the light reflecting sheet 40, for example, a thermoplastic resin such as an acrylic resin, a polycarbonate resin, a cyclic polyolefin resin, a polyethylene terephthalate resin, a polyethylene naphthalate resin, or a polyester resin, or a thermosetting resin such as an epoxy resin or a silicone resin may be used. In addition, as the light diffusing material, for example, a known material such as titanium oxide, silicon dioxide, aluminum oxide, zinc oxide, or glass may be used.

[0125] <Second Light Adjustment Member>

[0126] The planar light source 300 includes a light adjusting member (second light adjusting member) 60 disposed on the light guiding member 10 so as to face the light source 20 across the light guiding member 10 .

[0127] The second light adjustment component 60 is a component used to weaken the light directly above the light source 20 on the light extraction surface of the planar light source 300 so as to make the brightness of the light extraction surface close to uniform. As the transmittance of such a second light adjustment component 60, it is preferably, for example, 20% to 60% with respect to the light from the light source 20, and more preferably 30% to 40%. In the second light adjustment component 60, as in the first light adjustment component 24A, a material that reflects light, such as a resin material containing a light diffusion material or a metal material, can be used. The second light adjustment component 60 in this embodiment covers the entire light source 20 when viewed from above, and its outer edge has a circular shape, but it can also have a rectangular shape. In addition, the second light adjustment component 60 is film-shaped in this embodiment, but it can also be dot-shaped.

[0128] <Light reflecting parts>

[0129] The planar light source 300 includes a light reflecting member 70 at a position away from the light source 20 , and the light reflecting member 70 surrounds the light source 20 in a rectangular frame shape in a plan view.

[0130] 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 on the light reflecting sheet 40 along the outer periphery of the light guide member 10. The light reflecting member 70 divides the light guide member 10 according to each light source 20, thereby suppressing the light guide between adjacent partitions. Thus, local dimming of the light emitting area can be controlled in units of partitions.

[0131] 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 a plan view, the length of one side of the rectangular frame-shaped light reflecting member 70 is greater than that of one side of the light source 20, for example, 5 to 30 times.

[0132] The inner side surface of the light reflecting member 70 is convexly curved toward the light source 20 in the present embodiment, but may also be concavely curved. In particular, the cross-sectional shape of the light reflecting member 70 is preferably such that the width becomes narrower as it moves away from the light reflecting sheet 40 in the height direction, thereby being able to efficiently extract the light from the light source 20 toward the light extraction surface side of the planar light source 300. The inner side surface of the light reflecting member 70 may be a single plane, a single curved surface, a combination of planes having different inclinations relative to the light reflecting sheet 40, a combination of multiple curved surfaces having different curvatures, or a combination of a plane and a curved surface.

[0133] The reflectivity of the light reflecting member 70 to the light from the light source 20 is preferably 60% or more, and more preferably 90% or more. The light reflecting member 70 can be made of, for example, a resin containing a light diffusing material. As the resin used for the light reflecting member 70, a thermoplastic resin such as an acrylic resin, a polycarbonate resin, a cyclic polyolefin resin, a polyethylene terephthalate resin, or a polyester resin, or a thermosetting resin such as an epoxy resin or a silicone resin can be used. In addition, as the light diffusing material, a known material such as titanium oxide, silicon dioxide, aluminum oxide, zinc oxide, or glass can be used.

[0134] <Wiring substrate>

[0135] The wiring substrate 30 includes an insulating substrate 34, a wiring layer 32 disposed on the insulating substrate 34 and electrically connected to the positive and negative electrodes 21, and a cover layer 36 covering the wiring layer 32. The wiring substrate 30 also includes third through holes 31 that are connected to the first through holes 41 and penetrate the wiring layer 32.

[0136] As the wiring substrate 30 , for example, a rigid substrate or a flexible substrate can be used.

[0137] Note that the wiring substrate 30 has a surface on which the light source 20 is not arranged as a first surface, and a surface opposite to the first surface as a second surface.

[0138] The wiring layer 32 is a path member for applying a voltage to the light source 20. Figure 4 As shown, the shape of the wiring layer 32 in the portion where the third through hole 31 is arranged may be wider than that of other linear wiring layers.

[0139] The wiring layer 32 can be made of a metal material, 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 a conductive paste containing metal powder thereof. The shape of the metal powder may be, for example, spherical, flake, or needle-shaped.

[0140] The wiring layer 32 is arranged on the insulating base material 34 .

[0141] The material of the insulating substrate 34 is, for example, an insulating resin material such as phenolic resin, epoxy resin, polyimide resin, BT resin, polyphthalamide, etc. A ceramic material such as alumina, aluminum nitride, etc. may also be used for the insulating substrate 34. In addition, the insulating substrate 34 may also be a structure in which an insulating member is arranged in layers on the surface of a metal member.

[0142] The cover layer 36 is a member for protecting the wiring layer 32. The cover layer 36 may be configured to cover the entire insulating substrate 34. Figure 4As shown, the cover layer 36 has an opening 37 so as to expose the third through hole 31 and the wiring layer 32 arranged around the third through hole 31. As a material of the cover layer 36, an insulating material such as polyimide can be used.

[0143] <Conductive Parts>

[0144] The conductive member 50 is a member that electrically connects the electrode 21 and the wiring layer 32 .

[0145] As described above, the first through holes 41 are arranged on the light reflecting sheet 40 in a manner that they are opposite to each electrode 21 of the positive and negative pair of the light source 20, and the third through holes 31 are arranged on the wiring substrate 30 in communication with the first through holes 41. That is, there is a path from the electrode 21 to the wiring layer 32 that makes one electrode 21 correspond to one third through hole 31. The conductive members 50 are arranged on the paths to electrically connect the electrodes 21 and the wiring layer 32.

[0146] As a material of the conductive member 50 , in addition to the same material as the wiring layer 32 , for example, a known material such as tin-silver-copper (SAC)-based solder or tin-bismuth (SnBi)-based solder can be used.

[0147] 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 on the light reflecting sheet 40 side. Here, the surface of the wiring layer 32 opposite to the surface on the light reflecting sheet 40 side is the first surface of the wiring substrate 30. On the first surface side of the wiring substrate 30, for example, Figure 4 As shown, the third through hole 31 is arranged at a position overlapping with the wiring layer 32 when viewed from above, in other words, the third through hole 31 is arranged at a position closer to the inside than the outer edge of the wiring layer 32. The contact between the wiring layer 32 and the conductive component 50 is arranged at the exposed portion of the wiring layer 32 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 wiring layer 32 around the third through hole 31, and can be reliably electrically connected. In addition, the inner side surface of the third through hole 31 in the present embodiment is arranged in such a way 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 substrate 34 become the same plane, but it can also be arranged in such a way that the inner side surface of the through hole of the wiring layer 32 is closer to the outside than the inner side surface of the through hole of the insulating substrate 34. That is, when viewed from above, the width of the through hole of the wiring layer 32 can also be larger than the width of the through hole of the insulating substrate 34. In addition, the wiring layer 32 may be arranged 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 may be arranged only in a portion of the periphery of the through hole of the insulating base material 34 .

[0148] <Protective parts>

[0149] In addition to the above-mentioned structure, the planar light source 300 may include a protective member 80 covering the opening 37 of the cover layer 36 of the wiring substrate 30. The protective member 80 is an insulating member that protects the wiring layer 32 and the conductive member 50 from short circuit.

[0150] The protective member 80 can be made of phenyl silicone resin, dimethyl silicone resin, epoxy resin, acrylic resin, or polyurethane resin. In addition, the protective member 80 may be light-transmissive, or may be made opaque by adding a pigment such as titanium oxide. In particular, by making the protective member 80 light-transmissive, the connection state between the wiring layer 32 and the conductive member 50 can be visually confirmed, which is more preferred.

[0151] According to the planar light source 300 having the structure described above, the conductive member 50 is connected to the electrode 21 via the first through hole 41 arranged in the light reflecting sheet 40 in a manner that the electrodes 21 forming a positive and negative pair of the light source 20 are opposite to each other. Therefore, in the planar light source 300, the entire lower surface of the light source 20 except for the electrode 21 is opposite to the light reflecting sheet 40, and the light of the light source 20 can be effectively used. In addition, since the electrodes 21 forming a positive and negative pair are arranged separately, regardless of the shape and arrangement of the electrodes 21, such as Figure 3C As shown, there is an area 25 between a pair of positive and negative electrodes 21 of the light source 20 on the lower surface of the light source 20. The area 25 is also opposite to the light reflecting sheet 40, so the light of the light source 20 can be used more effectively. In this way, the planar light source 300 can increase the area of ​​the light reflecting sheet 40 opposite to the light source 20, and can reduce the area of ​​the wiring layer 32 and the like that is 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.

[0152] Note that the number of light sources 20 disposed on the wiring substrate 30 may be one or more. The number of light sources 20 can be appropriately selected according to the size and shape of the planar light source 300. In addition, the intervals between the light sources 20 can be appropriately adjusted.

[0153] <Method for Manufacturing Planar Light Source of First Embodiment>

[0154] Next, regarding the method for manufacturing the planar light source 300 of the first embodiment, refer to Figure 1 to Figure 9C , Fig. 22 An example thereof will be described.

[0155] The manufacturing method of the planar light source 300 includes: a light emitting module preparation step S1, preparing a light emitting module 100, the light emitting module 100 having a light source 20, a light guide member 10 and a first light reflecting sheet 40, the light source 20 having a positive and negative pair of electrodes 21 on one side, the light guide member 10 covering the light source 20 in a manner that the electrodes 21 are exposed, and the first light reflecting sheet 40 having a first through hole 41 corresponding to each of the positive and negative electrodes 21 of the light source 20 in a one-to-one relationship; a wiring substrate preparation step S2, preparing a wiring substrate 30, the wiring substrate 30 having a wiring layer 32 electrically connected to the electrodes 21; a light emitting module bonding step S3, bonding the light emitting module 100 to the wiring substrate 30; and a connection step S4, electrically connecting the electrodes 21 to the wiring layer 32 via the conductive member 50 disposed in the first through hole 41. Note that, here, the light emitting module preparation step S1 and the wiring substrate preparation step S2 may be performed first, or may be performed simultaneously.

[0156] <Light-emitting module preparation process>

[0157] 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 reflecting sheet 40. Note that in the steps of the manufacturing method, the planar light source 300 is Figure 5 The light emitting module 100 shown or a unit formed by arranging a plurality of light emitting modules 100 is configured by combining with a wiring substrate 30. Note that 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.

[0158] In addition, the case where a plurality of light emitting modules 100 are formed by singulating the light emitting module 100 after forming the light emitting module 100 is described here. Here, singulation includes not only the case of singulation into a light source 20 but also the case of singulation into a light source 20 or more. And the singulated light emitting modules can be bonded to the wiring substrate 30 in the light emitting module bonding step described later.

[0159] First, if Fig. 7A As shown, a first through hole 41 is provided on the light reflecting sheet in such a manner that one first through hole 41 corresponds to one electrode 21 of the light source 20, thereby forming the first light reflecting sheet 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 is substantially consistent with the shape of the electrode 21 when viewed from above. Note that the first through hole 41 can be formed by, for example, using a drill or a laser, in addition to punching. In addition, a light reflecting sheet having a first through hole 41 can also be purchased.

[0160] Next, if Figure 7BAs shown, the light source 20 is arranged on the first light reflecting sheet 40 so that the first through hole 41 faces the electrode 21 . The region 25 between the positive and negative electrodes 21 on the surface of the light source 20 having the electrodes 21 faces the first light reflecting sheet 40 .

[0161] Then, if Figure 7C As shown in FIG. 1 , the light reflecting member 70A is arranged to surround the light source 20 at a certain distance. Figure 6 As shown, the light reflecting member 70A forms a grid shape when viewed from above. Each grid of the light reflecting member 70A surrounds one light source 20 at the center. The light reflecting member 70A can be formed, for example, by applying a material of the light reflecting member 70A in a state of moderate viscosity to the first light reflecting sheet 40. The cross section of the light reflecting member 70A, as an example, can be a shape such as an ellipse cut in half at a short diameter, but can also be a triangular shape, or a rectangular shape, for example.

[0162] Then, if Fig.7D As shown, the light guide component 10 is arranged in a manner covering the light source 20. For example, the light guide component 10 can be arranged by injecting a resin that becomes the material of the light guide component 10 into the area surrounded by the frame formed by the light reflecting component 70A and curing it. Note that the injection of the resin can be performed from the nozzle of a dispenser, or can be applied by screen printing, spraying, or these methods can be used simultaneously. In this manufacturing method, as a result, the position where the light source 20 is pre-arranged becomes the light source arrangement portion 11 in the light guide component 10. Since the lower surface of the light source 20 is not covered by the light guide component 10, the electrode 21 is exposed from the light guide component 10 and faces the first through hole 41 of the first light reflecting sheet 40. The entire lower surface of the light source 20 except the electrode 21 faces the first light reflecting sheet 40, and the light from the light source 20 can be effectively utilized. Note that the light guide component 10 can also be prepared by injection molding, transfer molding, or by purchasing a molded component.

[0163] Then, if Fig. 7E As shown, the light adjusting member 60 is arranged on the light guide member 10 so as to face the light source 20 across the light guide member 10. For example, the light adjusting member 60 can be formed by applying a resin that becomes the material of the light adjusting member 60 on the light guide member 10 and curing it. At this stage, the assembly 150 of the light emitting module 100 before singulation is formed.

[0164] Then, if Figure 7F As shown, the light emitting module 100 assembly 150 is cut into individual pieces at the grid lines 70B of the light reflecting member 70A. 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.

[0165] <Wiring Board Preparation Step>

[0166] The wiring substrate preparation step S2 is a step of preparing the wiring substrate 30 for bonding the light emitting module 100. Here, the wiring substrate 30 is provided with third through holes 31 that communicate with the first through holes 41 and penetrate the wiring layer 32. Fig. 8A FIG. 1 shows a cross-sectional view of the wiring substrate 30A before the third through hole 31 is formed. Figure 8B FIG. 1 shows a cross-sectional view of the wiring substrate 30 after the third through hole 31 is formed.

[0167] First, the wiring layer 32A is disposed on the insulating base material 34A, and the cover layer 36 is disposed so as to cover the wiring layer 32A, thereby forming the wiring substrate 30A. The cover layer 36 is provided so as to be provided with the conductive member 50 in the subsequent process. Figure 4 As shown, as an example, the opening 37 is formed in advance so that the location where the third through hole 31 is to be formed and its surroundings are exposed.

[0168] Next, on the wiring substrate 30A before the third through hole 31 is formed, the third through hole 31 is formed in such a manner as to be connected to the first through hole 41 of the first light reflecting sheet 40 and to penetrate the wiring layer 32. The third through hole 31 can be formed, for example, by processing based on punching, drilling, or laser. Note that the wiring substrate preparation step S2 can also be prepared by forming the wiring layer and the cover layer as described above, and then importing the wiring substrate having the third through hole 31.

[0169] <Light Emitting Module Bonding Process>

[0170] The light emitting module bonding step S3 is a step of bonding the wiring substrate 30 and the light emitting module 100 together.

[0171] like Fig.9A As shown in FIG. 1 , an adhesive resin is applied to the surface of the wiring substrate 30 to which the light emitting module 100 is to be bonded, and the first through hole 41 and the third through hole 31 are aligned so as to face each other, thereby bonding the light emitting module 100. The adhesive resin is omitted from the illustration. As the adhesive resin, for example, a known resin containing acrylic resin, epoxy resin, or polyurethane resin as a component can be used. Note that in Fig.9A However, the interval between the light emitting modules 100 may be set to, for example, about 1% to 10% of the width of the light emitting module 100, and can be set appropriately.

[0172] Regarding the wiring substrate 30 to which the light emitting module 100 is bonded, if viewed from the side to which the light emitting module 100 is not bonded, the third through hole 31 is connected to the first through hole 41 of the first light reflecting sheet 40, and the front end of the first through hole 41 is blocked by the electrode 21 of the light source 20. That is, a hole portion having the electrode 21 as the bottom and the third through hole 31 as the entrance is formed according to the number of electrodes 21.

[0173] <Connection process>

[0174] The connecting step S4 is a step of electrically connecting the electrode 21 and the wiring layer 32 using the conductive member 50 . Fig. 9B 2 is a cross-sectional view when the connecting step S4 is completed.

[0175] First, the conductive component 50 is injected into the hole portion with the third through hole 31 as the entrance. When injecting the conductive component 50, the wiring substrate 30 bonded with the light emitting module 100 is placed horizontally with the light emitting module 100 side facing downward. The conductive component 50 needs to be sufficient to reach the electrode 21 as the bottom of the hole portion while ensuring the contact with the wiring layer 32 on the inner side of the third through hole 31. The conductive component 50 is injected in an amount that further diffuses onto the surface of the wiring layer 32 outside the third through hole 31. That is, the electrical connection contact between the conductive component 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 reflecting sheet 40 side, so that the electrical connection between the conductive component 50 and the wiring layer 32 is more reliable.

[0176] After the conductive member 50 is injected, a step of heating the conductive member 50 is performed (e.g., a reflow method). Note that the conductive member 50 may be provided separately for each hole portion as in the present embodiment, or may be provided so that adjacent holes are continuous and separated for each hole portion using a laser or the like before or after the conductive member 50 is heated. In addition, the conductive member 50 may be injected from a nozzle of a dispenser, or may be provided by screen printing, or may be injected from a nozzle and screen printed at the same time, for example, screen printing may be performed after injection from a nozzle.

[0177] <Protective member forming step>

[0178] In addition to the above steps, a protective component forming step S5 may be further performed. The protective component forming step S5 is a step of forming a protective component 80 that covers the conductive component 50 and the exposed wiring layer 32. Fig. 9C As shown, in the protection member forming step S5 , the protection member 80 is formed so as to cover the cover layer 36 located around the opening 37 .

[0179] As described above, by preparing the light emitting module 100 and the wiring substrate 30 separately, each process can be performed simultaneously or independently, so that the efficiency of the manufacturing process can be achieved. Since the manufacturing method is to adhere the light emitting module 100 or a unit formed by arranging a plurality of light emitting modules 100 to the wiring substrate 30, it is easy to adjust the interval and number of the light emitting modules 100.

[0180] [Second embodiment]

[0181] For the structure of the planar light source of the second embodiment, so that it is a planar light source 201 having one light emitting module, refer to Fig.10 Explain it.

[0182] The planar light source 201 is different from the planar light source 200 of the first embodiment in the structure of the conductive member. The other structures are the same as those of the first embodiment. Note that the description of the same parts as those of the first embodiment will be appropriately omitted.

[0183] <First Conductive Member and Second Conductive Member>

[0184] The conductive member of the planar light source 201 includes a first conductive member 51 disposed in the first through hole 41 and a second conductive member 52 disposed between the first conductive member 51 and the wiring layer 32. The electrode 21 and the wiring layer 32 are electrically connected via the first conductive member 51 and the second conductive member 52.

[0185] Note that the first conductive member 51 may be disposed in the first through hole 41 so as to be flat with the surface of the light reflecting sheet 40, may be disposed lower than the surface of the light reflecting sheet 40, or may be disposed 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. The material of the first conductive member 51 and the second conductive member 52 may be the same material or different materials.

[0186] Regarding the planar light source 201, the entire lower surface of the light source 20 except the electrode 21 is opposite to 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 to match the shape of the electrode 21. In addition, the first conductive member 51 can be selected from a material suitable for bonding with the electrode 21.

[0187] <Method for Manufacturing Planar Light Source of Second Embodiment>

[0188] For the method for manufacturing the planar light source of the second embodiment, refer to Figures 11A to 12B , Fig. 22An example thereof will be described. Note that the drawings show an example in which a plurality of light emitting modules are combined with a wiring substrate.

[0189] The light emitting module preparation step S12 and the connection step S42 in the method for manufacturing a planar light source of the second embodiment are different from those in the method for manufacturing a planar light source of the first embodiment described above. Other than these, the method is the same as the method for manufacturing a planar light source of the first embodiment.

[0190] <Connection process>

[0191] The connection step S42 in the method for manufacturing the planar light source of the second embodiment is to electrically connect the electrode 21 to the wiring layer 32 via the conductive member pre-arranged in the first through hole 41 of the first light reflecting sheet 40. Note that 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.

[0192] The process of setting the first conductive component 51 is performed in the light emitting module preparation process S12. Fig.11A , Fig. 11B As shown, 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. Note that the first conductive member 51 and the electrode 21 of the light source 20 are bonded using solder or the like. Fig. 12A , Fig. 12B As shown, the step of providing the second conductive member 52 is performed after the light emitting module 101 is bonded to the wiring substrate 30. Note that 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.

[0193] The manufacturing method of the second embodiment preliminarily provides a conductive member in the first through hole 41 , and other steps can be performed in the same manner as the first embodiment. Therefore, this manufacturing method can form the planar light source of the second embodiment while taking advantage of the manufacturing method of the first embodiment.

[0194] [Third Embodiment]

[0195] For an example of the structure of the planar light source of the third embodiment, let it be a planar light source 202 having one light emitting module, refer to Fig.13 Explain it.

[0196] The structure of the light reflecting sheet of the planar light source 202 is different from that of the planar light source 200 of the first embodiment. The other structures are the same as those of the first embodiment. In addition, the description of the same parts as those of the first embodiment is appropriately omitted.

[0197] <First Light Reflecting Sheet and Second Light Reflecting Sheet>

[0198] The light reflecting sheet of the planar light source 202 includes a first light reflecting sheet 40 having a first through hole 41 and a second light reflecting sheet 45 having a second through hole 46 that is opposite to the first through hole 41 and in which the light source 20 is disposed.

[0199] The planar light source 202 is the same as the planar light source 200 of the first embodiment, and the entire lower surface of the light source 20 except the electrode 21 is opposite to the first light reflecting sheet 40, so that the light of the light source 20 can be effectively used. In addition, the planar light source 202 can reduce the area of ​​the wiring layer 32 and the like that is irradiated with light by making the area 25 between the electrodes 21 of the light source 20 opposite to the first light reflecting sheet 40. In addition, the planar light source 202 is configured so that the first light reflecting sheet 40 and the second light reflecting sheet 45 overlap 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.

[0200] <Method for Manufacturing Planar Light Source of Third Embodiment>

[0201] For the method for manufacturing the planar light source of the third embodiment, refer to Figure 14 to Figure 17C , Fig. 22 An example thereof will be described. Note that the drawings show an example in which a plurality of light emitting modules are combined with a wiring substrate.

[0202] The manufacturing method of the planar light source of the third embodiment includes: a wiring substrate preparation step S2A, in which a first light reflecting sheet 40 having a first through hole 41 is arranged on a wiring substrate 30 having a wiring layer 32 so that the wiring layer 32 is opposite to the first through hole 41, the wiring layer 32 is electrically connected to the electrode 21 of the light source 20 having a pair of positive and negative electrodes 21 on one side, and the first through hole 41 is opposite to each of the positive and negative electrodes 21 of the light source 20; a light emitting module preparation step S1A, in which a light emitting module having a light source 20, a second light reflecting sheet 45 and a light guide component 10 is prepared. 102, the second light reflecting sheet 45 has a second through hole 46 opposite to the first through hole 41 and configured with the light source 20, the light guide member 10 covers the light source 20 in a manner that the electrode 21 is exposed, the light source 20 is configured in the second through hole 46, and the light source 20 is configured on the light guide member 10; the light emitting module bonding step S3A, the first light reflecting sheet 40 is sandwiched in a manner that the electrode 21 is opposite to the first through hole 41, and the light emitting module 102 is bonded to the wiring substrate 30; the connecting step S4, the electrode 21 is electrically connected to the wiring layer 32 via the conductive member 50 configured in the first through hole 41. Note that here, either the light emitting module preparation step S1A or the wiring substrate preparation step S2A can be performed first, or they can be performed simultaneously.

[0203] <Light-emitting module preparation process>

[0204] The light emitting module preparation step S1A is a step of preparing a light emitting module 102 including at least the light source 20, the light guide member 10 and the second light reflecting sheet 45. Note that in the steps of the manufacturing method, the planar light source 202 is Fig.14 The light emitting module 102 shown or a unit formed by arranging a plurality of light emitting modules 102 is combined with a first light reflecting sheet 40 and a wiring board 30. 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.

[0205] Note that here, the case where a plurality of light emitting modules 102 are formed by singulating the aggregate of the light emitting modules 102 will be described. Here, too, singulation includes not only the case of singulation into a case of having one light source 20, but also the case of singulation into a case of having two or more light sources 20. Furthermore, the singulated light emitting modules can be bonded to the wiring substrate 30 in the light emitting module bonding step described later.

[0206] First, if Fig.15A As shown, a second through hole 46 for arranging the light source 20 is formed on the second light reflecting sheet 45. For example, the second through hole 46 can be formed by punching using a punch having a shape similar to the shape of the light source 20 when viewed from above. Note that in addition to punching, the second through hole 46 can also be formed by using a drill or a laser, etc. A light reflecting sheet having the second through hole 46 can also be purchased.

[0207] Next, if Fig. 15B as well as Fig. 15C As shown, the second light reflecting sheet 45 is overlapped and fixed to the support plate P which will be removed later, and the light source 20 is arranged in the second through hole 46 .

[0208] Next, as in the first embodiment, Figure 15D to Figure 15G As shown, the light reflecting member 70A, the light guiding member 10 and the light adjusting member 60 are formed. Then, the support plate P is removed. At this stage, the assembly 152 of the light emitting modules 102 before being singulated is formed.

[0209] As in 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. In addition, since the lower surface of the light source 20 is not covered by the light guide member 10, the electrode 21 is exposed from the light guide member 10.

[0210] Then, as in the first embodiment, Fig.15H As shown, the assembly 152 of the light emitting modules 102 is cut into individual pieces at the grid lines 70B of the light reflecting member 70A.

[0211] <Wiring Board Preparation Step>

[0212] The wiring substrate preparation step S2A is a step of preparing the first light reflecting sheet 40 and the wiring substrate 30 for bonding the light emitting module 102. The first through holes 41 of the first light reflecting sheet 40 are arranged so that one first through hole 41 faces one electrode 21 of the light source 20. The first light reflecting sheet 40 is arranged on the wiring substrate 30 at a position where the wiring layer 32 faces the first through hole 41. Moreover, here, the third through holes 31 are formed on the wiring substrate 30, which are connected to the first through holes 41 and pass through the wiring layer 32.

[0213] In the wiring substrate preparation step S2A, it is preferred to simultaneously form the first through hole 41 of the first light reflecting sheet 40 and the third through hole 31 of the wiring substrate 30. That is, it is preferred that through holes facing the electrodes 21 forming a positive and negative pair of electrodes 21 of the light source 20 are formed one-to-one on the bonded substrate 90A formed by bonding the first light reflecting sheet 40A before the first through hole 41 is formed and the surface of the wiring substrate 30A before the third through hole 31 is formed on the side to which the light emitting module 102 is bonded, so that the first through hole 41 and the third through hole 31 are formed continuously.

[0214] First, as in the first embodiment, Fig.16A As shown in FIG. 1 , the wiring substrate 30A is formed before the third through hole 31 is formed. Fig. 16B As shown in FIG. 1 , a bonded substrate 90A is formed by bonding the first light reflecting sheet 40A before forming the first through hole 41 to the surface of the wiring substrate 30A on the side to which the light emitting module 102 is to be bonded. Fig. 16C As shown, on the laminated substrate 90A, for each electrode 21, a through hole is formed to face the electrode 21 of the light source 20. Thus, by simultaneously forming the first through hole 41 and the third through hole 31, the alignment accuracy of the first light reflecting sheet 40 and the wiring substrate 30 can be improved.

[0215] <Light Emitting Module Bonding Process>

[0216] The light emitting module bonding step S3A is a step of bonding the wiring substrate 30 and the light emitting module 102 together.

[0217] In the light emitting module bonding step S3A of the third embodiment, the first light reflecting sheet 40 is interposed so that the electrode 21 faces the first through hole 41, and the light emitting module 102 is bonded to the wiring substrate 30. An adhesive resin is applied to the first light reflecting sheet 40. Fig.17AAs shown, the light emitting module 102 is bonded so that the electrode 21 faces the first through hole 41. The bonding resin is omitted from the figure. Note that if a sheet having adhesive properties such as an adhesive sheet is used as the first light reflecting sheet 40, the application of the bonding resin can be omitted.

[0218] Regarding the wiring substrate 30 after the light emitting module 102 is bonded, if viewed from the side on which the light emitting module 102 is not bonded, the third through hole 31 is connected to the first through hole 41 of the first light reflecting sheet 40, and the front end of the first through hole 41 is blocked by the electrode 21 of the light source 20. That is, a hole portion having the electrode 21 as the bottom and the third through hole 31 as the entrance is formed according to the number of electrodes 21. The area 25 between the positive and negative electrodes 21 on the surface of the light source 20 having the electrode 21 is opposite to the first light reflecting sheet 40.

[0219] <Connection Step and Protection Component Formation Step>

[0220] like Fig. 17B As shown, the connection step S4 is performed in the same manner as in the first embodiment. In addition, the protection component forming step S5 is then performed, so that Fig. 17C As shown, for example, the protection member 80 can be formed so as to cover the conductive member 50 and the exposed wiring layer 32 , and further cover the cover layer 36 located around the opening 37 .

[0221] <Modification of Light Source>

[0222] Note that the light source is not limited to the structure of the light source 20 shown. For example, a light source having a pair of positive and negative electrodes 21 on one side and emitting blue or white light may be used. FIG. 18A to FIG. 18D Provide explanation.

[0223] like Fig.18A As shown, the light source 20A includes a light emitting element 22 that emits blue light and a translucent component 23A. The translucent component 23A contains a fluorescent substance that emits yellow light, which can make the light color of the light source 20A white. In addition, the light source 20A includes a first light adjustment component 24A on the upper surface, and a light reflecting layer 24B on the surface with the electrode 21, that is, the lower surface. By including the light reflecting layer 24B on the surface with the electrode 21, the light source 20A can reduce the light reaching the wiring layer 32.

[0224] like Fig.18B As shown, the light source 20B includes a light emitting element 22 that emits blue light and a light-transmitting member 23A, and can make the light emission color white. In addition, the light source 20B includes a first light adjustment member 24A on the upper surface.

[0225] The light-transmitting 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 stack of the light-emitting element 22 and the lower surface of the light-transmitting member 23A are respectively covered by the covering member 26. The covering member 26 is a member that covers the light-emitting element 22 to protect it and reflects the light from the light-emitting element 22 to the side of the light-transmitting member 23A. For example, silicone resin, epoxy resin, acrylic resin, etc. can be listed as the material used for the covering member 26. For example, the covering member 26 contains a light diffusion material such as titanium oxide, barium titanate, aluminum oxide, silicon oxide, etc.

[0226] The light-transmitting member 23A of the light source 20A or 20B may be a light-transmitting member 23B that does not contain a fluorescent substance. In addition, the light-transmitting members 23A or 23B may contain a light-diffusing material. Examples of materials used for the light-diffusing material include titanium oxide, barium titanate, aluminum oxide, and silicon oxide.

[0227] Note that the light sources 20A and 20B may have a structure including the light reflecting layer 24B on the lower surface side of the light emitting element 22 and not including the first light adjusting member 24A, or may have a structure not including the first light adjusting member 24A and the light reflecting layer 24B.

[0228] In addition, if Fig.18C , Fig.18D As shown in the figure, as a modification of the light source 20, light sources 20C and 20D in which the light emitting element 22 is not sealed by the light-transmitting member 23A and the covering member 26 can also be used. The light source 20C has a first light adjustment member 24C disposed on the upper surface of the light emitting element 22. In addition, the light source 20D has a light reflecting layer 24D disposed on the surface of the light source 20C having the electrode 21.

[0229] Note that, as the material used for the first light adjustment members 24A and 24C, similar to the first embodiment, for example, a resin material containing a light diffusion material or a metal material can be used. In addition, as the first light adjustment members 24A and 24C, a dielectric multilayer film or a film in which a dielectric multilayer film and a metal film are laminated can be used.

[0230] <Modification of the Method for Forming the Light Guide Member>

[0231] In addition, in the manufacturing method of the first embodiment, the light guide component 10 is formed by solidifying a liquid resin, but a pre-formed light guide component (hereinafter referred to as a light guide plate) may also be used. Note that the liquid state mentioned here also includes a paste state. In addition, although it is described here as a modified example of the first embodiment, it is also applicable to other embodiments.

[0232] like Fig.19AAs shown, the light guide plate 15a has a concave light source placement portion 11 on its lower surface that is large enough to surround the light source 20, and the light guide plate 15a covers the light source 20 so as to expose the electrode 21. The light source 20 is placed in the light source placement portion 11 via a light-transmitting adhesive.

[0233] In addition, if Fig.19B As shown, the light source arrangement portion 11 may be a through hole. Alternatively, after arranging the light source 20 in the through hole of the light guide plate 15a1, a liquid resin may be injected in a manner to cover the upper surface of the light source 20 and cured to form the light guide component 15b. In this example, the light guide component composed of the light guide plate 15a1 and the light guide component 15b covers the light source 20 in a manner to expose the electrode 21. Note that the resin material of the light guide plate 15a1 and the resin material of the light guide component 15b may be the same or different. In addition, the light guide plate 15a1 may be a single layer or a multilayer. For example, in the case where the light guide plate 15a1 is composed of multiple layers, an adhesive sheet may be used to bond the layers together. The material of the adhesive sheet may be any material that is translucent to the light emitted from the light source 20. In order to reduce the occurrence of interfaces between the layers, it is preferred to use the same material as the light guide plate 15a1.

[0234] In addition, if Fig.19C As shown, a light guide component 15c including a first light guide plate 15c1 and a second light guide plate 15c2 may also be used. The first light guide plate 15c1 has a through hole for configuring the light source 20. The thickness of the first light guide plate 15c1 is substantially the same as the thickness of the light source 20. Moreover, the second light guide plate 15c2 is configured to cover the upper surface of the light source 20 and the upper surface of the first light guide plate 15c1. In this example, a recessed portion formed by combining the first light guide plate 15c1 and the second light guide plate 15c2 is the light source configuration portion 11, and the light guide component 15c covers the light source 20 in such a manner that the electrode 21 is exposed. Note that the resin material of the first light guide plate 15c1 and the second light guide plate 15c2 may be the same or different.

[0235] When using a light guide plate, Fig. 20C as well as Fig.20D As shown, after the light guide plate 15a1 is arranged on the first light reflecting sheet 40, the light reflecting member 75A is arranged. In this case, a part of the light emitting module preparation process is changed. As an example, refer to Figures 20A to 20F The light emitting module preparation step S1B in the case of using the light guide plate 15a1 will be described.

[0236] Similar to the light emitting module preparation step S1 in the first embodiment, the light source 20 is arranged on the first light reflecting sheet 40 having the first through hole 41 formed therein so that the first through hole 41 faces the electrode 21 .

[0237] Next, the light guide plates 15a1 are disposed adjacent to each other on the first light reflecting sheet 40 so that the light source 20 is accommodated in the light source arrangement portion 11. Then, a resin that becomes the material of the light guide member 15b is injected into the light source arrangement portion 11 in the through hole and cured so that the light source 20 is covered. 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 electrode 21 is exposed.

[0238] Next, the material of the light reflecting component 75A is injected into the gap between the adjacent light guide plates 15a1 and cured. Then, as in the first embodiment, the light adjusting component (second light adjusting component) 60 is arranged on the light guide plate 15a1 and the light guide component 15b. Then, the assembly 155 of the light emitting module 105 is cut at the grid line 75B of the light reflecting component 75A and is singulated. Note that although the second light adjusting component 60 in this embodiment covers the entire upper surface of the light guide component 15b, a portion of the upper surface of the light guide component 15b can also be exposed from the second light adjusting component 60.

[0239] In this way, when the light reflecting member 75A is formed by coating 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 side surface of the light guiding member. Therefore, by adjusting the shape of the outer side surface of the light guiding member in advance, the shape of the inner side surface of the light reflecting member 75 can be adjusted.

[0240] In addition, as another modification of the first embodiment, air may be used as the light guide member.

[0241] <Modification of Wiring Board>

[0242] Next, refer to Fig.21 A modified example of the wiring substrate is described. In this modified example, the wiring substrate 30B does not have the third through hole 31. Therefore, it is configured as follows. The electrical connection contacts between the conductive component 50 and the wiring layer 32 are provided on the surface of the wiring layer 32 on the light reflecting sheet 40 side, which are respectively opposite to the first through holes 41.

[0243] The insulating substrate 34B has openings that are respectively opposite to the first through holes 41 of the light reflecting sheet 40, exposing the wiring layer 32B. The portions of the wiring layer 32B that are respectively opposite to the first through holes 41 are thicker than other portions in the thickness direction of the wiring substrate 30B. In addition, in this modification, the surface of the wiring layer 32B is substantially flush with the surface of the insulating substrate 34B. A conductive component 50 is disposed between the wiring layer 32B and the electrode 21 via the first through holes 41. Note that the portions of the wiring layer 32B that are respectively opposite to the first through holes 41 may protrude from the surface of the insulating substrate 34B or may be lower than the surface of the insulating substrate 34B. The difference in thickness of the wiring layer 32B can be adjusted according to the thickness of the conductive component 50.

[0244] In addition, in the manufacturing method of the planar light source based on the wiring substrate 30B without the third through hole 31, for example, in the light emitting module bonding process, before bonding the light emitting module, the conductive component 50 is arranged on the wiring layer 32B. That is, the conductive component 50 is arranged on the upper surface of the wiring layer 32B in advance, and the light emitting module is bonded. At this time, the conductive component 50 is connected to the electrode 21 of the light source 20 via the first through hole 41. In addition, the contact point between the conductive component 50 and the wiring layer 32B is arranged on the surface of the wiring layer 32B on the side of the first light reflecting sheet 40, which is respectively opposite to the first through hole 41.

[0245] The wiring board 30B does not need to form the opening 37 in the cover layer 36B. Therefore, it is not necessary to arrange the protection member 80 that covers the opening 37 of the cover layer 36, and the number of steps in the manufacturing method can be reduced.

[0246] The modified example of the wiring substrate can also be applied to the first embodiment and other embodiments. For example, the conductive component 50 can also be pre-configured 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 component 50 is bonded to the electrode 21 of the light source 20 and the wiring layer 32B using solder or the like. Note that the wiring layer can also be multiple layers instead of one layer. The embodiment in which the wiring substrate has the third through hole 31 and the modified example in which the wiring substrate does not have the third through hole 31 can also be implemented in the same manner when the wiring layer is multiple layers.

Claims

1. A planar light source, characterized in that: have: A light source having a pair of positive and negative electrodes on one side; a light guide member covering the light source in a manner that the electrode is exposed; a wiring substrate having a wiring layer electrically connected to the electrodes; A light reflecting sheet, which is sandwiched between the light guide component and the wiring substrate, and has first through holes corresponding to the electrodes forming a positive and negative pair; The electrode and the wiring layer are electrically connected by a conductive member arranged via the first through hole. The light reflecting sheet comprises: A first light reflecting sheet having the first through hole; The second light reflecting sheet has a second through hole facing the first through hole and in which the light source is disposed.

2. The planar light source according to claim 1, characterized in that: The contact points between the conductive member and the wiring layer are arranged at portions of the surface of the wiring layer on the light reflecting sheet side that are opposite to the first through holes.

3. The planar light source according to claim 1, characterized in that: The wiring substrate has third through holes that are connected to the first through holes and penetrate the wiring layer, respectively, and the contact between the conductive member and the wiring layer is arranged at least inside the third through holes.

4. The planar light source according to claim 3, characterized in that: 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 on the light reflecting sheet side.

5. The planar light source according to any one of claims 1 to 4, characterized in that: The conductive member includes 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.

6. The planar light source according to any one of claims 1 to 4, characterized in that: The planar light source further includes a light adjustment member disposed on the light guide member so as to face the light source across the light guide member.

7. The planar light source according to any one of claims 1 to 4, characterized in that: The planar light source further includes a light reflecting member surrounding the light source.

8. The planar light source according to any one of claims 1 to 4, characterized in that: An area between a pair of positive and negative electrodes on a surface of the light source having electrodes faces the light reflecting sheet.

9. The planar light source according to any one of claims 1 to 4, characterized in that: A plurality of the light sources are arranged on the wiring substrate.

10. A method for manufacturing a planar light source according to any one of claims 1 to 9, characterized in that: Include: A wiring substrate preparation step, wherein a first light reflecting sheet having a first through hole is arranged on a wiring substrate having a wiring layer so that the wiring layer is opposite to the first through hole, the wiring layer is electrically connected to the electrode of a light source having a pair of positive and negative electrodes on one side, and the first through hole is opposite to each of the positive and negative electrodes in a pair; a light emitting module preparation step, preparing a light emitting module including the light source, a second light reflecting sheet and a light guiding member, wherein the second light reflecting sheet has a second through hole opposite to the first through hole and in which the light source is arranged, the light guiding member covers the light source in a manner that the electrode is exposed, the light source is arranged in the second through hole, and the light source is arranged on the light guiding member; A light emitting module bonding step, wherein the first light reflecting sheet is sandwiched so that the electrode faces the first through hole, and the light emitting module is bonded to the wiring substrate; The connecting step electrically connects the electrode and the wiring layer via a conductive member disposed in the first through hole.

11. The method for manufacturing a planar light source according to claim 10, characterized in that: In the connecting step, contacts between the conductive member and the wiring layer are arranged at portions of the surface of the wiring layer on the first light reflecting sheet side that are opposed to the first through holes.

12. The method for manufacturing a planar light source according to claim 10, characterized in that: In the wiring substrate preparation step, third through holes are formed on the wiring substrate, each of which is connected to the first through holes and penetrates the wiring layer. In the connecting step, a contact point between the conductive member and the wiring layer is arranged at least inside the third through hole.

13. The method for manufacturing a planar light source according to claim 10, characterized in that: In the wiring substrate preparation step, on a bonded substrate formed by bonding the first light reflecting sheet before forming the first through hole to the surface of the wiring substrate on the side to which the light-emitting module is bonded, through holes are formed that are opposite to each of the electrodes forming a positive and negative pair, thereby continuously forming the first through holes and forming third through holes that are connected to the first through holes and penetrate the wiring layer. In the connecting step, a contact point between the conductive member and the wiring layer is arranged at least inside the third through hole.

14. The method for manufacturing a planar light source according to claim 12 or 13, characterized in that: In the connecting step, a contact point between the conductive member and the wiring layer is arranged on a surface of the wiring layer opposite to a surface on the first light reflecting sheet side.

15. The method for manufacturing a planar light source according to any one of claims 10 to 13, characterized in that: In the light emitting module preparation step, a light adjustment member is disposed on the light guide member so as to face the light source with the light guide member interposed therebetween.

16. The method for manufacturing a planar light source according to any one of claims 10 to 13, characterized in that: In the light emitting module preparation step, a light reflecting member surrounding the light source is further arranged.

17. The method for manufacturing a planar light source according to any one of claims 10 to 13, characterized in that: The area between the positive and negative electrodes on the surface of the light source having the electrodes is made to face the first light reflecting sheet.

18. The method for manufacturing a planar light source according to any one of claims 10 to 13, characterized in that: In the light emitting module bonding step, a plurality of the light emitting modules are arranged on the wiring substrate.

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