Planar light source and method for manufacturing the same

Abstract

Provided is a planar light source capable of suppressing occurrence of connection failure in an electrical connection configuration of a wiring layer and an electrode, and a manufacturing method thereof. A planar light source (100) includes: a wiring substrate (110) having an insulating layer (116) provided with a first through-hole (116a) and a second through-hole (116b), and a first wiring layer (113) and a second wiring layer (114); a light source (120) having a first electrode (124b) and a second electrode (124c); a light guide member (130); a first wiring member (151) having a first portion (151a) filled in the first through-hole and electrically connected to the first electrode, and a second portion (151b) disposed below the insulating layer, connected to the first portion, and connected to the first wiring layer; and a second wiring member (152) having a third portion (152a) filled in the second through-hole and electrically connected to the second electrode, and a fourth portion (152b) disposed below the insulating layer, connected to the third portion, and connected to the second wiring layer, the first wiring layer and the second wiring layer being disposed to sandwich the first through-hole and the second through-hole when viewed from above.

Description

Technical Field

[0001] The implementation method relates to a planar light source and a method for manufacturing the same. Background Technology

[0002] For example, a planar light source is widely used in the backlight of a liquid crystal display, which includes a wiring substrate, a light source disposed on the wiring substrate, and a light guide component disposed on the wiring substrate and surrounding the light source.

[0003] A known wiring substrate has the following configuration: an insulating layer and two wiring layers disposed beneath the insulating layer and corresponding to two electrodes in a light source. As a configuration for electrically connecting each wiring layer to its corresponding electrode in such a wiring substrate, a known configuration is as follows: two through-holes are provided in the insulating layer, a conductive component is disposed within each through-hole, and each conductive component is connected to its corresponding electrode and its corresponding wiring layer.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-192095 Summary of the Invention

[0007] The problem that the invention will solve

[0008] The purpose of this embodiment is to provide a planar light source and a method thereof that can suppress the generation of poor connection in the electrical connection structure between the wiring layer in the wiring substrate and the electrode of the light source.

[0009] Methods for solving problems

[0010] The planar light source of the embodiment includes: a wiring substrate having: an insulating layer having a first through-hole and a second through-hole spaced apart from each other; a first wiring layer and a second wiring layer disposed under the insulating layer and separated from the first through-hole and the second through-hole; a light source disposed on the wiring substrate having a first electrode and a second electrode spaced apart from each other; a light guide member disposed on the wiring substrate surrounding the light source; a first wiring member having a first portion and a second portion, the first portion filling the first through-hole and electrically connected to the first electrode, the second portion being disposed under the insulating layer, connected to the first portion, and connected to the first wiring layer; and a second wiring member having a third portion and a fourth portion, the third portion filling the second through-hole and electrically connected to the second electrode, the fourth portion being disposed under the insulating layer, connected to the third portion, and connected to the second wiring layer. In a top view, the first wiring layer and the second wiring layer are configured to sandwich the first through-hole and the second through-hole.

[0011] The planar light source of the embodiment includes: a wiring substrate having: an insulating layer having a first through-hole and a second through-hole spaced apart from each other; a first wiring layer and a second wiring layer disposed below the insulating layer and separated from the first through-hole and the second through-hole; and a cover layer covering the area around the first through-hole and the second through-hole on the lower surface of the insulating layer such that the first through-hole and the second through-hole are exposed, and exposing a portion of the first wiring layer and the second wiring layer; a light source disposed on the wiring substrate having a first electrode and a second electrode spaced apart from each other; and a light guide component having... The first wiring component, having a first portion and a second portion, is placed on the wiring substrate and surrounds the light source; the first portion fills the first through-hole and is electrically connected to the first electrode, the second portion is connected to the first portion and is connected to the portion of the first wiring layer exposed from the cover layer via the lower surface of the cover layer; and the second wiring component, having a third portion and a fourth portion, the third portion fills the second through-hole and is electrically connected to the second electrode, the fourth portion is connected to the third portion and is connected to the portion of the second wiring layer exposed from the cover layer via the lower surface of the cover layer.

[0012] The method for manufacturing a planar light source according to the embodiment includes: a step of preparing a wiring substrate having: an insulating layer having a first through hole and a second through hole spaced apart from each other; a first wiring layer and a second wiring layer disposed below the insulating layer and separated from the first through hole and the second through hole, wherein, in a top view, the first wiring layer and the second wiring layer are configured to sandwich the first through hole and the second through hole; a step of disposing a light guide member and a light source on the wiring substrate; and a step of forming a first wiring component and a second wiring component, wherein the first wiring component fills the first through hole, is disposed below the insulating layer, is connected to the first wiring layer, and is electrically connected to a first electrode of the light source, and the second wiring component is separated from the first wiring component, fills the second through hole, is disposed below the insulating layer, is connected to the second wiring layer, and is electrically connected to a second electrode of the light source.

[0013] Invention Effects

[0014] According to this embodiment, a planar light source and a method thereof can be provided that can suppress the generation of poor connection in the electrical connection structure between the wiring layer in the wiring substrate and the electrode in the light source. Attached Figure Description

[0015] Figure 1 This is a schematic top view showing the planar light source of the first embodiment.

[0016] Figure 2 It is a magnified schematic top view showing a luminous area of ​​a planar light source and its surroundings.

[0017] Figure 3 yes Figure 2 A schematic cross-sectional view of line III-III.

[0018] Figure 4A This is a schematic top view showing an enlarged portion of the wiring substrate.

[0019] Figure 4B This is a schematic bottom view showing a portion of the wiring board.

[0020] Figure 5A It is shown in magnification Figure 3 A schematic cross-sectional view of the light source in the image.

[0021] Figure 5B It is shown in magnification Figure 3 A schematic top view of the light source in the image.

[0022] Figure 6 It is a schematic top view showing a portion of the wiring substrate, a portion of the sheet laminate, and the light source.

[0023] Figure 7 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0024] Figure 8A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0025] Figure 8B It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0026] Figure 9 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0027] Figure 10A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0028] Figure 10B It is a schematic bottom view illustrating the manufacturing method of a planar light source.

[0029] Figure 11A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0030] Figure 11B It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0031] Figure 12It is a schematic bottom view showing the central part and the ends of the wiring board.

[0032] Figure 13A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0033] Figure 13B It is a schematic bottom view illustrating the manufacturing method of a planar light source.

[0034] Figure 14 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0035] Figure 15A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0036] Figure 15B This is a schematic cross-sectional view showing other examples of the shapes of the first wiring component, the second wiring component, and the cover layer.

[0037] Figure 15C This is a schematic cross-sectional view showing other examples of the shapes of the first wiring component, the second wiring component, and the cover layer.

[0038] Figure 16 This is a schematic cross-sectional view showing a portion of the planar light source according to the second embodiment, enlarged.

[0039] Figure 17 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0040] Figure 18 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0041] Figure 19 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0042] Figure 20 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0043] Figure 21 This is an enlarged schematic top view showing a portion of the wiring substrate, a portion of the sheet laminate, and the light source of the planar light source according to the third embodiment.

[0044] Figure 22 This is a schematic cross-sectional view showing the planar light source of the fourth embodiment.

[0045] Figure 23 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0046] Figure 24 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0047] Figure 25 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0048] Figure 26 This is a schematic cross-sectional view illustrating the manufacturing method of the planar light source according to the fifth embodiment.

[0049] Figure 27 This is a schematic cross-sectional view showing the planar light source of the sixth embodiment.

[0050] Figure 28 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0051] Figure 29 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0052] Figure 30 This is a schematic bottom view showing the light source and a portion of the wiring substrate in the planar light source of the seventh embodiment, enlarged.

[0053] Figure 31A yes Figure 30 A schematic cross-sectional view of the XXXI-XXXI line.

[0054] Figure 31B This is a schematic bottom view showing other examples of light sources and wiring substrates.

[0055] Figure 32A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0056] Figure 32B It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0057] Figure 33 This is a schematic bottom view showing an enlarged portion of the wiring substrate in the planar light source of the eighth embodiment.

[0058] Figure 34 This is a schematic top view showing the planar light source of the ninth embodiment.

[0059] Figure 35 This is an enlarged view of the light-emitting module in the ninth embodiment, showing the components... Figure 34 A schematic top view of the area enclosed by the dashed line XXXV.

[0060] Figure 36 yes Figure 35 A schematic cross-sectional view of the XXXVI-XXXVI line.

[0061] Figure 37It is an amplification of the light-emitting module in the ninth embodiment, which consists of Figure 34 The area enclosed by XXXV is shown in a schematic top view with perspective, illustrating the wiring pattern.

[0062] Figure 38 It is an enlarged view of the data. Figure 34 A schematic bottom view of the portion enclosed by the dashed line XXXVIII.

[0063] Figure 39 This is an enlarged view of the wiring substrate in the ninth embodiment, showing the components... Figure 38 A schematic bottom view of the portion enclosed by the dashed line XXXIX.

[0064] Figure 40 This is an enlarged view of the wiring substrate and light-emitting module in the ninth embodiment, showing the components... Figure 38 A schematic bottom view of the portion enclosed by the dashed line XXXIX.

[0065] Figure 41 yes Figure 40 A schematic cross-sectional view of the XLI-XLI line.

[0066] Figure 42 This is a schematic bottom view showing other examples of wiring substrates.

[0067] Figure 43 This is a schematic bottom view showing a portion of the wiring substrate in the modified example.

[0068] Explanation of reference numerals in the attached figures

[0069] 100, 200, 300, 400, 600, 700, 800, 1000: Planar light source

[0070] 110, 210, 710, 910: Wiring substrate

[0071] 111, 211, 711: Basal layer

[0072] 112, 212, 712: First covering layer

[0073] 113, 213, 713: First wiring layer

[0074] 113a, 713a: Front end

[0075] 113b: Middle section

[0076] 113c: Upper surface

[0077] 113d: Lower surface

[0078] 113e: Side view

[0079] 113s1: First region (the region opposite to the first through hole)

[0080] 113s2: Second Region

[0081] 113s3: Third Region

[0082] 114, 214: Second wiring layer

[0083] 114a, 714a: Front end

[0084] 114b: Middle section

[0085] 114c: Upper surface

[0086] 114d: Lower surface

[0087] 114e: Side view

[0088] 114s1: First region (the region opposite to the second through hole)

[0089] 114s2: Second Region

[0090] 114s3: Third Region

[0091] 115, 215, 715, 815: Second cover layer

[0092] 115a: Through hole

[0093] 116, 216, 716, 911: Insulation layer

[0094] 116a, 216a, 716a: First through hole

[0095] 116b, 216b, 716b: Second through hole

[0096] 117, 217: Light-reflective sheets

[0097] 118a, 218a, 718: Adhesive sheets

[0098] 118b, 218b: Adhesive sheets

[0099] 119, 219: Sheet laminates

[0100] 119a, 219a, 718a: Third through hole

[0101] 119b, 219b, 718b: Fourth through hole

[0102] 120, 320, 620: Light source

[0103] 121, 321: Main body

[0104] 122, 322: First terminal

[0105] 123, 323: Second terminal

[0106] 124, 624: Light-emitting elements

[0107] 124a, 624a, 621a: Light-emitting part

[0108] 124b, 324b, 624b, 621b: First electrode

[0109] 124c, 324c, 624c, 621c: Second electrode

[0110] 125, 623: Light-transmitting components

[0111] 126: First light adjustment component

[0112] 127, 624: Covering components

[0113] 130, 630: Light guide components

[0114] 131, 631: Light Source Configuration Department

[0115] 132, 632: Dividing slots

[0116] 133, 634: Light-transmitting components

[0117] 133a: First layer

[0118] 133b: Second layer

[0119] 133Fa, 533Fa: First resin component

[0120] 133Fb: Second resin component

[0121] 134: Second light adjustment component

[0122] 135, 633: Divide into components

[0123] 151, 251, 451, 751: First wiring components

[0124] 151a, 451a, 751a: Part 1; 151b, 451b, 751b: Part 2

[0125] 151F, 251F, 451Fa, 751F: First conductive paste

[0126] 152, 252, 452, 752: Second wiring components

[0127] 152a, 452a, 752a: Part Three

[0128] 152b, 452b, 752b: Part Four

[0129] 152F, 252F, 452Fa, 752F: Secondary conductive paste

[0130] 153: Overlay

[0131] 451Fb: Third conductive paste

[0132] 452Fb: Fourth conductive paste

[0133] First opening: 715a

[0134] Second opening: 715b

[0135] Third opening: 715c, 815c

[0136] Fourth opening: 715d, 815d

[0137] 900: Drill bit

[0138] D1~D7: Distance

[0139] E1, E2: Distance

[0140] F1, F2: Size

[0141] G: Direction of gravity

[0142] L1, L2: Diagonals

[0143] L3: Axis

[0144] R: Light-emitting area

[0145] S1: First gap

[0146] S2: Second gap

[0147] c1~c4: Center Detailed Implementation

[0148] <First Implementation>

[0149] First, the first embodiment will be described.

[0150] Figure 1 This is a schematic top view illustrating the planar light source of this embodiment.

[0151] Figure 2 It is a magnified schematic top view showing a luminous area of ​​a planar light source and its surroundings. Figure 3 yes Figure 2 A schematic cross-sectional view of line III-III.

[0152] The planar light source 100 in this embodiment is as follows: Figure 3 As shown, the light source 100 includes a wiring substrate 110, a light source 120 disposed on the wiring substrate 110, and a light guide member 130 disposed on the wiring substrate 110 and surrounding the light source 120. Hereinafter, each part of the planar light source 100 will be described in detail.

[0153] Furthermore, in the following description, an XYZ orthogonal coordinate system is used. The direction from the wiring substrate 110 toward the light source 120 is defined as the "Z direction". A direction orthogonal to the Z direction is defined as the "X direction", and a direction orthogonal to both the X and Z directions is defined as the "Y direction". The "Z direction" is also referred to as the "up direction", and its opposite direction as the "down direction", but these designations are for convenience and are unrelated to the direction of gravity. Additionally, observing the object directly with the naked eye from above, or observing it through it appropriately, is called "viewing from above". Similarly, observing the object directly with the naked eye from below, or observing it through it appropriately, is called "viewing from below".

[0154] In addition, in this embodiment, such as Figure 1 As shown, the light guide member 130 has multiple light source arrangement sections 131 along the X and Y directions. Each light source 120 is arranged within its respective light source arrangement section 131. However, the number of light sources arranged is not particularly limited as long as there is one or more. Furthermore, the light guide member 130 has dividing grooves 132 that divide the light-emitting area R of each light source 120 when viewed from above. Hereinafter, the description will mainly focus on the portion located within one light-emitting area R when viewed from above; however, the portions located within other light-emitting areas R when viewed from above can be constructed similarly unless otherwise specifically mentioned.

[0155] Wiring substrate 110, such as Figure 3 As shown, it has a base layer 111, a first cover layer 112 disposed on the base layer 111, a first wiring layer 113 disposed below the base layer 111 and corresponding to a light source 120, a second wiring layer 114, and a second cover layer 115 disposed below the base layer 111.

[0156] The substrate 111 is made of an insulating material. Examples of insulating materials constituting the substrate 111 include epoxy, silicone, liquid crystal polymer, polyimide (PI), polyethylene terephthalate (PET), or polyethylene naphthalate (PEN) resins.

[0157] The first cover layer 112 is made of an insulating material. Examples of insulating materials constituting the first cover layer 112 include epoxy, silicone, liquid crystal polymer, polyimide (PI), polyethylene terephthalate (PET), or polyethylene naphthalate (PEN) resin materials.

[0158] In this specification, in a wiring substrate, the insulating layer located above the first wiring layer and the second wiring layer is referred to as an "insulating layer". Therefore, in this embodiment, the base layer 111 and the first cover layer 112 correspond to "insulating layer 116". However, the composition of the insulating layer is not limited to the above. For example, in a wiring substrate, an insulating adhesive layer may be disposed between the base layer and the first cover layer. In this case, the base layer, the first cover layer, and the adhesive layer correspond to the insulating layer. Alternatively, for example, the first cover layer may not be provided above the base layer. In this case, only the base layer corresponds to the insulating layer. Additionally, the first wiring layer and the second wiring layer may be disposed below the second cover layer. In this case, the first cover layer, the base layer, and the second cover layer correspond to the insulating layer. Insulating adhesive layers may also be disposed between the first cover layer and the base layer, and between the base layer and the second cover layer.

[0159] The insulating layer 116 has a first through hole 116a and a second through hole 116b that are separated from each other. Each through hole 116a and 116b penetrates the insulating layer 116 along the Z direction (vertical direction). The inner surface of each through hole 116a and 116b is, for example, substantially parallel to the Z direction.

[0160] Figure 4A This is a schematic top view showing an enlarged portion of the wiring substrate.

[0161] Figure 4B This is a schematic bottom view showing a portion of the wiring board.

[0162] like Figure 4A As shown, the through holes 116a and 116b are circular in shape when viewed from above. However, the shape of the through holes when viewed from above is not limited to the above; for example, they can be polygons such as quadrilaterals, polygons with rounded corners, or shapes other than circles such as ellipses. The first through hole 116a and the second through hole 116b are arranged along the X direction. However, the first through hole and the second through hole can also be arranged along the Y direction. They can also be arranged in a direction that intersects with respect to the X and Y directions.

[0163] Each of the first wiring layer 113 and the second wiring layer 114 is made of a metallic material such as copper (Cu). The first wiring layer 113 and the second wiring layer 114 are separated from each other. Each of the first wiring layer 113 and the second wiring layer 114 is separated from the first through hole 116a and the second through hole 116b.

[0164] The first wiring layer 113 has a front portion 113a located on the side of the light source 120, a middle portion 113b connected to the front portion 113a, and an external connection portion located on the side of the middle portion 113b opposite to the front portion 113a. Similarly, the second wiring layer 114 has a front portion 114a located on the side of the light source 120, a middle portion 114b connected to the front portion 114a, and an external connection portion located on the side of the middle portion 114b opposite to the front portion 114a. The planar light source 100 is illuminated by supplying power to the external connection portion.

[0165] The wiring board 110 may also be configured to have a protruding area that protrudes outward from the end of the wiring board 110 when viewed from above, and an external connection portion is disposed in the protruding area.

[0166] The external connection part can also be electrically connected to another component (e.g., a substrate with drive circuitry). When electrically connecting the external connection part to another component, a connector can also be used, and from the viewpoint of thinness, a conductive sheet can also be used.

[0167] Viewed from above, the first wiring layer 113 and the second wiring layer 114 are configured to sandwich the first through-hole 116a and the second through-hole 116b. In this specification, "the first wiring layer and the second wiring layer are configured to sandwich the first through-hole and the second through-hole when viewed from above" means that, when viewed from above, the first through-hole and the second through-hole are disposed between the first wiring layer and the second wiring layer, and no first wiring layer and the second wiring layer are disposed between the first through-hole and the second through-hole. In this embodiment, the front end portion 113a of the first wiring layer 113 and the front end portion 114a of the second wiring layer 114 are configured to sandwich the first through-hole 116a and the second through-hole 116b.

[0168] In this embodiment, the top view of the front end portion 113a of the first wiring layer 113 is arc-shaped. The surface of the front end portion 113a is as follows: Figure 3 As shown, it includes an upper surface 113c in contact with the insulating layer 116, a lower surface 113d located on the opposite side of the upper surface 113c, and a side surface 113e located between the upper surface 113c and the lower surface 113d.

[0169] Side 113e is parallel to the Z direction. However, the side can also be curved instead of parallel to the Z direction. Side 113e is as follows: Figure 4A As shown, it has a first region 113s1 opposite to the first through hole 116a when viewed from above, a second region 113s2 located on the opposite side of the first region 113s1, and a third region 113s3 located between the first region 113s1 and the second region 113s2.

[0170] The first region 113s1, viewed from above, is concave, for example, arc-shaped, in the direction away from the first through hole 116a. The second region 113s2, viewed from above, is curved in the same direction as the first region 113s1, for example, arc-shaped. The third region 113s3, viewed from above, is a straight line parallel to the Y direction. However, the shapes of the first, second, and third regions are not limited to the above. For example, the first and second regions could be straight lines parallel to the Y direction, and the third region could be a straight line parallel to the X direction.

[0171] In this embodiment, the top view of the front end portion 114a of the second wiring layer 114 is arc-shaped. The surface of the front end portion 114a is as follows: Figure 3 As shown, it includes an upper surface 114c in contact with the insulating layer 116, a lower surface 114d located on the opposite side of the upper surface 114c, and a side surface 114e located between the upper surface 114c and the lower surface 114d.

[0172] Side 114e is parallel to the Z direction. However, the side can also be curved instead of parallel to the Z direction. Side 114e is as follows: Figure 4A As shown, it has a first region 114s1 opposite to the second through hole 116b when viewed from above, a second region 114s2 located on the opposite side of the first region 114s1, and a third region 114s3 located between the first region 114s1 and the second region 114s2.

[0173] The shape of the first region 114s1, viewed from above, is concave, for example, arc-shaped, in the direction away from the second through hole 116b. The shape of the second region 114s2, viewed from above, is curved in the same direction as the first region 114s1, for example, arc-shaped. The shape of the third region 114s3, viewed from above, is a straight line parallel to the Y direction. However, the shapes of the first, second, and third regions, viewed from above, are not limited to the above. For example, the shapes of the first and second regions could be straight lines parallel to the Y direction, and the shape of the third region could be a straight line parallel to the X direction.

[0174] The middle portion 113b of the first wiring layer 113 and the middle portion 114b of the second wiring layer 114 each extend along the Y direction. However, the direction in which each middle portion extends is not limited to the above; it can also be the X direction, or a direction inclined relative to the X and Y directions, and the direction in which the middle portion extends can also vary. In addition, the direction in which the first wiring layer extends can also be different from the direction in which the second wiring layer extends.

[0175] Second covering layer 115 Figure 4BAs shown, a portion of the lower surface of the substrate layer 111 is covered. Additionally, a through-hole 115a is provided in the second cover layer 115. The through-hole 115a penetrates the second cover layer 115 along the Z-direction (vertical direction). From the through-hole 115a, other portions of the substrate layer 111, a portion of the front end portion 113a and the middle portion 113b of the first wiring layer 113, a portion of the front end portion 114a and the middle portion 114b of the second wiring layer 114, a portion of the first wiring component 151 (described later), and a portion of the second wiring component 152 are exposed. Figure 4A As shown, the through hole 115a in top view is oblong. However, the shape of the through hole in top view is not limited to the above, and can also be a polygon such as a quadrilateral, or a circle.

[0176] The thickness of the wiring substrate 110 is, for example, 50 μm or more and 250 μm or less. When the thickness of the wiring substrate 110 is within the above range, the insulating layer of the wiring substrate is prone to deformation such as shrinkage or expansion due to changes in the environment such as temperature or humidity.

[0177] like Figure 3 As shown, a light-reflective sheet 117 is disposed on the wiring substrate 110. The light-reflective sheet 117 is adhered to the wiring substrate 110 using an adhesive sheet 118a. The light-reflective sheet 117 reflects a portion of the light emitted from the light source 120. Without the light-reflective sheet 117, sometimes a portion of the light from the light source 120 is absorbed by the base layer 111 of the wiring substrate 110, causing the base layer 111 to deteriorate. Therefore, by disposing of the light-reflective sheet 117 on the wiring substrate 110, it is possible to suppress the arrival of light from the light source 120 on the wiring substrate 110. This suppresses the absorption of light by the base layer 111 of the wiring substrate 110 and prevents the deterioration of the base layer 111. The light-reflective sheet 117 is preferably disposed on the upper surface of the wiring substrate 110 in the region excluding the first through-hole 116a and the second through-hole 116b. Therefore, since the light-reflective sheet 117 is disposed below the light source 120, it is even more effective to suppress the light arriving at the wiring substrate 110. Furthermore, the light from the light source 120 is reflected by the light-reflective sheet 117, allowing the light from the light source 120 to be transmitted further away within the light guide member 130, thus suppressing brightness unevenness within the light-emitting area R. The light-reflective sheet 117 can be composed of a resin sheet containing multiple air bubbles (e.g., a foamed resin sheet) or a resin sheet containing a light-diffusing material. As the resin used in the light-reflective sheet 117, thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefins, polyethylene terephthalate (PET), or polyester, or thermosetting resins such as epoxy or silicone, can be used. As the light-diffusing material, titanium dioxide, silica, alumina, zinc oxide, or glass can be used.

[0178] The materials of each wiring component 151 and 152 are primarily thermosetting materials, while the main component of the light-reflective sheet 117 can also be a thermoplastic resin. In this case, the melting point of the light-reflective sheet 117 is preferably higher than the curing temperature of the wiring components 151 and 152. Therefore, even when the curing temperature of each wiring component 151 and 152 is reached, the light-reflective sheet 117 will not melt, thus suppressing the reduction of light reflectivity. If the main component of the wiring component is epoxy resin, the curing temperature of the wiring component is approximately 120 to 130 degrees Celsius. Alternatively, if the main component of the light-reflective sheet 117 is polyethylene terephthalate, the melting point of the light-reflective sheet is approximately 220 degrees Celsius.

[0179] A light guide component 130 is disposed on the light reflective sheet 117. The light guide component 130 is adhered to the light reflective sheet 117 by means of an adhesive sheet 118b. The light reflective sheet 117 and the two adhesive sheets 118a and 118b are referred to as "sheet laminate 119".

[0180] The sheet laminate 119 covers the upper surface of the wiring substrate 110, exposing the first through hole 116a and the second through hole 116b. Specifically, the sheet laminate 119 has a third through hole 119a located directly above the first through hole 116a and a fourth through hole 119b located directly above the second through hole 116b.

[0181] The third through hole 119a, viewed from above, has the same shape as the first through hole 116a, for example, it is circular. The inner surface of the third through hole 119a is, for example, a plane that is the same as the inner surface of the first through hole 116a, and is approximately parallel to the Z-direction. The fourth through hole 119b, viewed from above, has the same shape as the second through hole 116b, for example, it is circular. The inner surface of the fourth through hole 119b is, for example, a plane that is the same as the inner surface of the second through hole 116b, and is approximately parallel to the Z-direction. That is, the first through hole 116a and the third through hole 119a form a generally cylindrical through hole, and the second through hole 116b and the fourth through hole 119b form a generally cylindrical through hole.

[0182] However, the structure of the sheet laminate is not limited to the above. For example, instead of having two through holes corresponding to the first and second through holes as described above, a single through hole can be provided directly above the first and second through holes, exposing both the first and second through holes. Alternatively, the sheet laminate may not be provided in the planar light source.

[0183] Figure 5A It is shown in magnification Figure 3A schematic cross-sectional view of the light source in the image.

[0184] Figure 5B It is shown in magnification Figure 3 A schematic top view of the light source in the image.

[0185] Figure 6 It is a schematic top view showing a portion of the wiring substrate, a portion of the sheet laminate, and the light source.

[0186] Light source 120 Figure 5A As shown, it has a light-emitting element 124, a light-transmitting component 125, a first light-adjusting component 126, a covering component 127, a first terminal 122, and a second terminal 123.

[0187] The light-emitting element 124 has a light-emitting portion 124a and a first electrode 124b and a second electrode 124c disposed below the light-emitting portion 124a and separated from each other.

[0188] The light-emitting portion 124a, for example, has a semiconductor growth substrate and a semiconductor stack structure disposed beneath the semiconductor growth substrate. The semiconductor stack structure is configured to emit visible light or ultraviolet light, and any composition can be used depending on the desired emission peak wavelength. The semiconductor stack structure, for example, includes an InxAlyGa1-x-yN (0≤x, 0≤y, x+y≤1) layer, and emits blue light from the light-emitting portion 124a. However, the color of the light emitted by the light-emitting portion is not limited to blue.

[0189] A semiconductor stack-up structure includes an n-type semiconductor layer, a p-type semiconductor layer, and a light-emitting layer sandwiched between them. The light-emitting layer can also have a double heterojunction or a single quantum well (SQW) structure, or it can have a structure with an active layer group, such as a multiple quantum well (MQW).

[0190] Furthermore, the semiconductor stacked structure can also have a configuration that includes one or more light-emitting layers between an n-type semiconductor layer and a p-type semiconductor layer, or it can be a configuration formed by repeating the configuration of sequentially including an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer multiple times. When the semiconductor stacked structure includes multiple light-emitting layers, it can include light-emitting layers with different emission peak wavelengths, or it can include light-emitting layers with the same emission peak wavelength. Furthermore, the same emission peak wavelength may have a deviation of a few nanometers. The combination of emission peak wavelengths among multiple light-emitting layers can be appropriately selected. For example, when the semiconductor stacked structure includes two light-emitting layers, the light-emitting layers can be selected by combinations such as blue light with blue light, green light with green light, red light with red light, ultraviolet light with ultraviolet light, blue light with green light, blue light with red light, or green light with red light. Each light-emitting layer can also include multiple active layers with different emission peak wavelengths, or it can include multiple active layers with the same emission peak wavelength.

[0191] The first electrode 124b and the second electrode 124c are arranged along the X direction. The shapes of the electrodes 124b and 124c when viewed from above are as follows: Figure 5B As shown, it is a roughly triangular shape with rounded corners. However, the shape of each electrode when viewed from above is not limited to the above; for example, it can also be a quadrilateral or other polygon, a circle, or an ellipse.

[0192] like Figure 6 As shown, when viewed from above, the distance D1 between the center c1 of the first through hole 116a and the center c2 of the second through hole 116b is longer than the distance D2 between the center c3 of the first electrode 124b and the center c4 of the second electrode 124c (D1 > D2). However, the distance between the centers of the first and second through holes can also be equal to the distance between the centers of the first and second electrodes. Furthermore, when the first electrode 124b is triangular, the center c3 is the intersection of three lines connecting each vertex of the triangle to the midpoint of the side opposite to each vertex. The same applies to the center c4 of the second electrode 124c.

[0193] Light-transmitting component 125, etc. Figure 5A As shown, the light-emitting part 124a is covered on its upper surface and side surface. The light-transmitting component 125 is transparent to light emitted from the light-emitting part 124a. The light-transmitting component 125 includes a base material made of a light-transmitting material and a plurality of wavelength-converting particles dispersed in the base material. Materials used as the base material include, for example, silicone, epoxy, and glass. Wavelength-converting particles can be, for example, phosphors. Phosphors can be used, for example, yttrium aluminum garnet-based phosphors (e.g., YAG phosphors) or lutetium aluminum garnet-based phosphors (e.g., Lu3(Al,Ga)5O) as phosphors. 12Ce), terbium-aluminum-garnet phosphors (e.g., Tb3(Al,Ga)5O) 12 Ce), CCA-based fluorophores (e.g., Ca), 10 (PO4)6Cl2:Eu), SAE-based phosphors (e.g., Sr4Al) 14 O 25 Eu), chlorosilicate phosphors (e.g., Ca8MgSi4O) 16 Cl2:Eu), β-silicon phosphors (e.g., (Si,Al)3(O,N)4:Eu), α-silicon phosphors (e.g., Mz(Si,Al)). 12 (O, N) 16 Nitrogen-based phosphors include Eu (where 0 < z ≤ 2, and M is Li, Mg, Ca, Y, and lanthanum elements other than La and Ce), SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu) or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu), fluoride-based phosphors include KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2(Si,Al)F6:Mn) or MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), perovskite-structured phosphors (e.g., CsPb(F,Cl,Br,I)3), or quantum dot phosphors (e.g., CdSe, InP, AgInS2, or AgInSe2). The transparent component 125 may also contain multiple types of phosphors.

[0194] Alternatively, a wavelength conversion sheet containing the aforementioned phosphor can be disposed on a planar light source. The wavelength conversion sheet can be a planar light source that absorbs a portion of the blue light from the light source 120, emits yellow, green, and / or red light, and then emits white light. For example, a light source capable of emitting blue light can be combined with a wavelength conversion sheet containing a phosphor capable of emitting yellow light to obtain white light. In addition, a light source capable of emitting blue light can be combined with wavelength conversion sheets containing red and green phosphors. Furthermore, a light source capable of emitting blue light and multiple wavelength conversion sheets can be combined. 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 as multiple wavelength conversion sheets. Furthermore, a light-emitting element capable of emitting blue light, a light source containing a light-transmitting component containing a phosphor capable of emitting red light, and a wavelength conversion sheet containing a phosphor capable of emitting green light can be combined.

[0195] The light source 120 emits a mixture of light emitted from the wavelength conversion particles within the light-transmitting component 125 and light emitted from the light-emitting section 124a. The color of the mixed light is, for example, white. However, the light-transmitting component may not contain wavelength conversion particles. In this case, the light source may emit only blue light emitted from the light-emitting section.

[0196] The first light-adjusting component 126 covers the upper surface of the light-transmitting component 125. The first light-adjusting component 126 reflects a portion of the light emitted from the light-emitting portion 124a, allowing the remaining portion of the light emitted from the light-emitting portion 124a to pass through. The first light-adjusting component 126 is, for example, a resin containing a light-reflective material. Specifically, as the first light-adjusting component 126, a resin such as silicone or epoxy containing titanium dioxide as the light-reflective material can be used.

[0197] The cover member 127 covers the lower surface of the light-transmitting member 125 and the lower surface of the light-emitting part 124a. The cover member 127 is, for example, a resin containing a light-reflective material. Specifically, as the cover member 127, a resin such as silicone or epoxy containing titanium dioxide as the light-reflective material can be used.

[0198] The first terminal 122 and the second terminal 123 are made of metallic materials such as copper (Cu). The first terminal 122 is as follows: Figure 5A As shown, the lower end of the first electrode 124b is connected to the second electrode 124c. The lower end of the second electrode 123 is connected to the second electrode 124c. The first terminal 122 and the second terminal 123 are separated from each other.

[0199] Hereinafter, in the light source 120, the part excluding the two terminals 122 and 123 (light-emitting element 124, light-transmitting component 125, first light-adjusting component 126, and covering component 127) will be referred to as the "main body 121".

[0200] like Figure 5B As shown, the shape of the main body 121 when viewed from above is, for example, a quadrilateral. The main body 121 is configured such that one diagonal L1 is parallel to the X direction, and the other diagonals L2 are parallel to the Y direction. That is, the main body 121 is configured such that the four sides forming the outer periphery when viewed from above are inclined at 45 degrees relative to the X and Y directions.

[0201] The two electrodes 124b and 124c are configured to be approximately symmetrical with respect to the diagonal L2 when viewed from above. For example... Figure 6As shown, the two electrodes 124b and 124c and the two terminals 122 and 123 are located on diagonal L1. The size of the main body 121 is largest on diagonal L1 when viewed from above. Therefore, by arranging the two terminals 122 and 123 on diagonal L1, even when the area of ​​the light-emitting element 124 is small when viewed from above, it is possible to suppress the two terminals 122 and 123 from approaching each other. The two through holes 116a and 116b of the wiring substrate 110 are provided according to the positions of the two terminals 122 and 123. Therefore, by suppressing the two terminals 122 and 123 from approaching each other, it is possible to suppress the two through holes 116a and 116b from approaching each other. As a result, it is possible to suppress the short circuit caused by the electrical connection between the p-shaped semiconductor layer and the n-shaped semiconductor layer in the light-emitting element 124. However, the main body may also be configured such that each diagonal is inclined relative to the X and Y directions when viewed from above. Furthermore, the shape of the main body of the light source when viewed from above is not limited to the above; for example, it can be a polygon other than a quadrilateral such as a pentagon, or a circle. Also, the positions of the two electrodes are not limited to the above.

[0202] In a top view, a portion of the first electrode 124b overlaps with the first through-hole 116a in this embodiment. This shortens the distance between the first electrode 124b and the first wiring component 151 (described later), reducing the resistance between them. The same applies to the second electrode 124c. However, each electrode may also cover the entire area of ​​its corresponding through-hole in a top view. Alternatively, each electrode may not overlap with its corresponding through-hole in a top view.

[0203] The shape of the first terminal 122 when viewed from above is as follows Figure 5B The diagram shows a triangle. This increases the connection area between the first terminal 122 and the first wiring component 151, which will be described later. The shape of the second terminal 123, viewed from above, is a portion of a triangle symmetrical to the first terminal 122 with respect to diagonal L2 cut off. This makes it easy to distinguish between the positive and negative terminals. However, the shape of each terminal is not limited to the above; for example, it can be a quadrilateral or other polygon, a polygon with rounded corners, a circle, or an ellipse. Furthermore, the shapes of the first and second terminals can be the same.

[0204] When viewed from above, the area of ​​the first terminal 122 is larger than the area of ​​the first electrode 124b. Similarly, when viewed from above, the area of ​​the second terminal 123 is larger than the area of ​​the second electrode 124c. However, it is also possible that the area of ​​the first terminal is equal to the area of ​​the first electrode when viewed from above, and the area of ​​the second terminal is equal to the area of ​​the second electrode when viewed from above.

[0205] like Figure 6As shown, in a top view, the first terminal 122 covers the first through hole 116a, and the second terminal 123 covers the second through hole 116b. Specifically, the first terminal 122 is as follows: Figure 3 As shown, the opening above the third through hole 119a, which is directly above the first through hole 116a, is blocked, and the opening above the fourth through hole 119b, which is directly above the second through hole 116b, is blocked by the second terminal 123. However, if the planar light source does not have a sheet laminate, the first terminal may block the opening above the first through hole, and the second terminal may block the opening above the second through hole.

[0206] Furthermore, the configuration of the light source is not limited to the above. For example, the light source may not have terminals. When the light source does not have a first terminal, the first electrode is electrically connected to the first wiring component, and the second electrode is electrically connected to the second wiring component. Additionally, the number of light-emitting elements constituting the light source may be two or more. In this case, the electrodes on the positive side of each light-emitting element may be electrically connected to the same wiring layer in the wiring substrate, or they may be electrically connected to different wiring layers. The same applies to the electrodes on the negative side of each light-emitting element. Alternatively, the light source may consist only of light-emitting elements.

[0207] The first wiring layer 113 is electrically connected to the first electrode 124b via the first terminal 122 and the first wiring component 151. The second wiring layer 114 is electrically connected to the second electrode 124c via the second terminal 123 and the second wiring component 152.

[0208] In this embodiment, each wiring component 151 and 152 includes a base material made of resin and at least one metal particle disposed in the base material. In the base material, multiple metal particles are in contact with each other, electrically connecting each terminal 122 and 123 to each wiring layer 113 and 114. The resin material used in each wiring component 151 and 152 is the same in this embodiment, and examples include thermosetting resins such as epoxy. The metal particles used in each wiring component 151 and 152 in this embodiment include a core made of a first metal material such as copper (Cu) and a covering layer made of a second metal material such as gold (Au) covering the core. However, the metal particles used in each wiring component may also be made of only one metal material such as copper (Cu), silver (Ag), or gold (Au), or may be made of two or more metal particles.

[0209] The first wiring component 151 has a first portion 151a and a second portion 151b.

[0210] The first part 151a fills the first through hole 116a and the third through hole 119a. In this specification, "filling the through hole" does not mean completely burying the through hole, but rather substantially burying the through hole; for example, gaps may exist within the through hole. The shape of the first part 151a corresponds to the shape of the first through hole 116a and the third through hole 119a, for example, it is approximately cylindrical.

[0211] The upper end of the first part 151a is connected to the lower end of the first terminal 122, and the first part 151a is electrically connected to the first electrode 124b via the first terminal 122. Thus, in this specification, "electrical connection" between two components includes two components being directly connected and able to conduct electricity between the two components, and two components being indirectly connected via other conductive components and able to conduct electricity between the two components.

[0212] The second portion 151b is a thin-film portion in the first wiring component 151 located below the opening below the first through-hole 116a. The second portion 151b is connected to the first portion 151a, disposed below the insulating layer 116, and connected to the first wiring layer 113. The second portion 151b is as follows... Figure 4B As shown, the second portion 151b covers a portion of the opening on the lower side of the first through-hole 116a and a portion of the lower surface 113d of the front end portion 113a of the first wiring layer 113. Specifically, the second portion 151b exposes the area in the opening on the lower side of the first through-hole 116a located on the side of the second through-hole 116b in the X direction. However, the second portion may also cover the entire area of ​​the opening on the lower side of the first through-hole.

[0213] Similarly, the second wiring component 152, as Figure 3 As shown, it has a third part 152a and a fourth part 152b.

[0214] The third part 152a fills the second through hole 116b and the fourth through hole 119b. The shape of the third part 152a corresponds to the shape of the second through hole 116b and the fourth through hole 119b, for example, it is approximately cylindrical. The upper end of the third part 152a is connected to the lower end of the second terminal 123, and the third part 152a is electrically connected to the second electrode 124c via the second terminal 123.

[0215] The fourth portion 152b is a thin-film portion in the second wiring component 152 located below the opening below the second through-hole 116b. The fourth portion 152b is connected to the third portion 152a, disposed below the insulating layer 116, and connected to the second wiring layer 114. The fourth portion 152b is as follows... Figure 4BAs shown, the fourth portion 152b covers a portion of the opening on the lower side of the second through-hole 116b and a portion of the lower surface 114d of the front end portion 114a of the second wiring layer 114. Specifically, the fourth portion 152b exposes the area in the opening on the lower side of the second through-hole 116b located on the side of the first through-hole 116a in the X direction. This prevents contact between the second portion 151b and the fourth portion 152b. However, the fourth portion may also cover the entire area of ​​the opening on the lower side of the second through-hole.

[0216] The lower surfaces of the first wiring component 151 and the second wiring component 152 are as follows: Figure 3 As shown, it is covered by a cover layer 153. Specifically, the cover layer 153 is configured to cover the through-hole 115a of the second cover layer 115. Thus, the cover layer 153 covers the portions of the first wiring layer 113, the second wiring layer 114, the first wiring component 151, and the second wiring component 152 that are exposed from the second cover layer 115. The cover layer 153 is made of an insulating material. Examples of insulating materials used in the cover layer 153 include resin materials such as polyimide (PI), polyethylene terephthalate (PET), or polyethylene naphthalate (PEN).

[0217] The light guide component 130 is transparent to light emitted from the light source 120. Materials used for the light guide component 130 include, for example, thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefins, polyethylene terephthalate (PET), and polyester, thermosetting resins such as epoxy or silicone, or glass.

[0218] The light guide component 130 is composed of a plate-shaped component. However, the light guide component may also be composed of more than one light-transmitting layer instead of a plate-shaped component. When the light guide component is composed of multiple light-transmitting layers, adjacent light-transmitting layers may be bonded together using a light-transmitting adhesive sheet. As the material of the light-transmitting adhesive sheet, in order to reduce the occurrence of interfaces between the light-transmitting layer and the adhesive sheet, it is preferable to use the same material as the light-transmitting layer.

[0219] Each light source arrangement portion 131 provided on the light guide component 130 is a through hole that extends through the light guide component 130 along the Z direction (vertical direction). The shape of the light source arrangement portion 131 when viewed from above is as follows: Figure 2 As shown, it is circular. However, the shape of the light source arrangement part when viewed from above is not limited to the above; it can also be a quadrilateral or other polygon, a polygon with rounded corners, or an ellipse. In addition, the light source arrangement part can also be a recess provided on the lower surface of the light guide member.

[0220] like Figure 3As shown, a light-transmitting component 133 is provided within the light source configuration section 131. In this embodiment, the light-transmitting component 133 has a double-layer structure, having a first layer 133a provided in the gap between the light source 120 and the side of the light source configuration section 131, and a second layer 133b provided on top of the first layer 133a. However, the light-transmitting component may also be a single-layer structure, or it may be a structure with three or more layers.

[0221] In this embodiment, the first layer 133a seals the light source 120. However, the first layer may only be provided in the gap between the light source and the side of the light source mounting portion without sealing the light source. The upper surface of the first layer 133a is located below the upper surface of the light guide member 130. The upper surface of the first layer 133a is concave in the downward direction. However, the upper surface of the first layer may also be a flat surface parallel to the X and Y directions.

[0222] The upper surface of the second layer 133b is a flat surface parallel to the X and Y directions, and is approximately the same surface as the upper surface of the light guide component 130. However, the upper surface of the second layer may also be concave downwards, or may be located below the upper surface of the light guide component.

[0223] The first layer 133a and the second layer 133b are transparent to light emitted from the light source 120. The first layer 133a and the second layer 133b contain a transparent material. For example, the transparent material used in the first layer 133a and the second layer 133b can be a thermoplastic resin such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate (PET), or polyester, or a thermosetting resin such as epoxy or silicone. The second layer 133b may also contain wavelength conversion particles. However, it is also possible that no transparent component is provided within the light source arrangement section, and the light source arrangement section contains an air layer.

[0224] A second light adjustment component 134 is disposed on the light-transmitting component 133. The second light adjustment component 134 is as follows: Figure 2 The configuration shown is such that, when viewed from above, it covers the light source 120, leaving a portion of the light source arrangement portion 131 exposed. However, the second light adjustment member can also be configured to cover the entire area of ​​the light source arrangement portion when viewed from above. The second light adjustment member 134 reflects a portion of the light emitted from the light source 120, allowing the remaining portion of the light emitted from the light source 120 to pass through. The second light adjustment member 134 is, for example, a resin containing a light-reflective material. Specifically, as the second light adjustment member 134, a resin such as silicone or epoxy containing titanium dioxide as the light-reflective material can be used. The shape of the second light adjustment member 134 when viewed from above is as follows: Figure 2 As shown, it is a quadrilateral. However, the shape of the second light adjustment component when viewed from above is not limited to the above; for example, it can also be circular.

[0225] The dividing groove 132 provided on the light guide component 130 is as follows Figure 1 As shown, the grid extends along the X and Y directions. However, the shape of the dividing grooves is not limited to a grid shape, as long as they can optically divide each light-emitting area to a practically sufficient degree. For example, dividing grooves may not be provided at the intersections of the grid.

[0226] Dividing slot 132, etc. Figure 3 As shown, the light guide component 130 extends through the Z-direction (vertical direction). The side of the dividing groove 132 is parallel to the Z-direction. However, the configuration of the dividing groove is not limited to the above. For example, the side of the dividing groove may be inclined relative to the Z-direction, or it may be curved. In addition, the dividing groove may be a recess on the upper surface of the light guide component, a recess on the lower surface of the light guide component, or a hollow shape that does not reach the upper or lower surfaces of the light guide component. In addition, a portion of the dividing groove may be blocked. Furthermore, the dividing groove may be provided only on the light guide component or on the sheet laminate.

[0227] A dividing member 135 is disposed within the dividing groove 132. The dividing member 135 is, for example, a resin containing a light-reflective material. Specifically, as the dividing member 135, a resin such as silicone or epoxy containing titanium dioxide as a light-reflective material can be used.

[0228] The dividing member 135 fills the dividing groove 132, and the upper surface of the dividing member 135 is the same as the upper surface of the light guide member 130. However, the configuration of the dividing member is not limited to the above. For example, the dividing member may also be formed in a layer along the inner surface of the dividing groove, and the upper part of the dividing member may protrude upward beyond the upper surface of the light guide member. Alternatively, the dividing groove may not have a dividing member, and the interior of the dividing groove may be an air layer.

[0229] Next, the manufacturing method of the planar light source 100 of this embodiment will be described.

[0230] Figure 7 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0231] Figure 8A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0232] Figure 8B It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0233] Figure 9 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0234] Figure 10A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0235] Figure 10B It is a schematic bottom view illustrating the manufacturing method of a planar light source.

[0236] Figure 11A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0237] Figure 11B It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0238] First, such as Figure 7 As shown, a wiring substrate 110 is prepared. The wiring substrate 110 prepared here has an insulating layer 116 having mutually separated first through-holes 116a and second through-holes 116b, a first wiring layer 113 and a second wiring layer 114 disposed below the insulating layer 116 and separated from the first through-holes 116a and second through-holes 116b. Furthermore, a sheet laminate 119 is adhered to the upper surface of the wiring substrate 110. The sheet laminate 119 has a third through-hole 119a located directly above the first through-hole 116a, and a fourth through-hole 119b located directly above the second through-hole 116b.

[0239] The first through-hole 116a and the third through-hole 119a can be formed in one step, for example, by placing a sheet laminate 119 on the wiring substrate 110 and then using methods such as punching, drilling, or laser irradiation. Similarly, the second through-hole 116b and the fourth through-hole 119b can be formed in one step, for example, by placing a sheet laminate 119 on the wiring substrate 110 and then using the same method. However, it is also possible to place a sheet laminate with the third and fourth through-holes pre-formed on a wiring substrate with the first and second through-holes pre-formed.

[0240] Next, as Figure 8A As shown, a light guide member 130 with a light source configuration section 131 is disposed on the wiring substrate 110, and the light source configuration section 131 is used to configure the light source 120. The light guide member 130 is configured such that the third through hole 119a and the fourth through hole 119b are exposed from the light source configuration section 131. The light guide member 130 is adhered to the sheet laminate 119 by means of an adhesive sheet 118b.

[0241] Next, as Figure 8B As shown, a dividing groove 132 is formed in the light guide component 130.

[0242] Next, as Figure 9As shown, a light source 120 is disposed on a wiring substrate 110. The light source 120 is disposed within a light source placement section 131 such that, when viewed from above, a first terminal 122 covers a first through-hole 116a and a second terminal 123 covers a second through-hole 116b. Thus, the first terminal 122 blocks the opening of the third through-hole 119a on the light source 120 side, and the second terminal 123 blocks the opening of the fourth through-hole 119b on the light source 120 side.

[0243] At this time, a portion of the lower surface of the first terminal 122 and a portion of the lower surface of the second terminal 123 adhere to the adhesive sheet 118b of the sheet laminate 119. Thus, the light source 120 can be temporarily fixed to the wiring substrate 110.

[0244] Next, as Figure 10A As shown, to enhance the temporary fixation of the light source 120 to the wiring substrate 110 using the adhesive sheet 118b, a light-transmitting first resin member 133Fa is disposed in the gap between the side of the light source arrangement portion 131 and the light source 120. In this embodiment, the light-transmitting first resin member 133Fa is configured to seal the light source 120, and its upper surface is located below the upper surface of the light guide member 130. However, the amount of the first resin member used to enhance the temporary fixation of the light source can also be such that it blocks the gap between the side of the light source arrangement portion and each terminal without sealing the light source.

[0245] Next, in this embodiment, the first resin component 133Fa is cured. The cured first resin component 133Fa corresponds to the first layer 133a of the light-transmitting component 133. However, the first resin component may also be cured after the conductive pastes 151F and 152F, which will be described later, are applied.

[0246] At this time, as Figure 10B As shown, the first through hole 116a, the second through hole 116b, the front end portion 113a and a portion of the middle portion 113b of the first wiring layer 113, and the front end portion 114a and a portion of the middle portion 114b of the second wiring layer 114 are exposed to the outside through hole 115a of the second cover layer 115 provided on the wiring substrate 110.

[0247] Next, as Figure 11A as well as Figure 11B As shown, a first wiring component 151 and a second wiring component 152 are formed.

[0248] Specifically, firstly, such as Figure 11A As shown, the intermediate body having wiring substrate 110, sheet laminate 119, light source 120, and light guide component 130 is arranged in a manner that is approximately consistent with the direction of gravity G in the direction from wiring substrate 110 toward light source 120 (Z direction).

[0249] Next, the first conductive paste 151F is configured to fill the first through-hole 116a and the third through-hole 119a, and to be in contact with the insulating layer 116 and the first wiring layer 113. Additionally, the second conductive paste 152F is configured to fill the second through-hole 116b and the fourth through-hole 119b, and to be in contact with the insulating layer 116 and the second wiring layer 114.

[0250] The first conductive paste 151F configured in this way has a first portion 151Fa filling the first through-hole 116a and the third through-hole 119a, and a thin film-like second portion 151Fb connected to the first portion 151Fa and in contact with the insulating layer 116 and the first wiring layer 113. The second portion 151Fb exposes a portion of the first portion 151Fa. Therefore, during the period until the first conductive paste 151F cures, voids present in the first portion 151Fa can be easily released from the surface exposed by the second portion 151Fb within the first portion 151Fa. As a result, the voids contained in the cured first conductive paste 151F can be reduced.

[0251] Similarly, the second conductive paste 152F configured in this way has a third portion 152Fa filling the second through-hole 116b and the fourth through-hole 119b, and a thin film-like fourth portion 152Fb connected to the third portion 152Fa and in contact with the insulating layer 116 and the second wiring layer 114. The fourth portion 152Fb exposes a portion of the third portion 152Fa. Therefore, during the period until the second conductive paste 152F cures, voids present in the third portion 152Fa can be easily released from the surface exposed by the fourth portion 152Fb within the third portion 152Fa. As a result, the voids contained in the cured second conductive paste 152F can be reduced.

[0252] Each conductive paste 151F and 152F can be prepared simultaneously or sequentially. Each conductive paste 151F and 152F comprises an uncured resin material and one or more metal particles dispersed in the resin material. Examples of thermosetting resins constituting each conductive paste 151F and 152F include epoxy resins. The metal particles used in each conductive paste 151F and 152F, for example in this embodiment, include a core made of a first metal material such as copper (Cu) and a covering layer made of a second metal material such as gold (Au) covering the core. However, the metal particles used in each wiring component may also be composed of only one metal material such as copper (Cu), silver (Ag), or gold (Au). Each conductive paste 151F and 152F may further contain a volatile solvent.

[0253] As described above, the opening on the light source 120 side of the third through hole 119a is blocked by the first terminal 122, and the opening on the light source 120 side of the fourth through hole 119b is blocked by the second terminal 123. Therefore, leakage of each conductive paste 151F and 152F into the light source arrangement section 131 of the light guiding component 130 can be suppressed.

[0254] Furthermore, at this time, the gap between the side of the light source configuration section 131 and the light source 120 is sealed by the cured material of the first resin component 133Fa (the first layer 133a of the light-transmitting component 133). Therefore, even when the terminals 122 and 123 are not completely sealed by the corresponding through holes 119a and 119b, the cured material of the first resin component 133Fa can further suppress the leakage of each conductive paste 151F and 152F into the light source configuration section 131.

[0255] Next, as Figure 11B As shown, the first conductive paste 151F and the second conductive paste 152F are cured. When the resin material constituting each conductive paste 151F and 152F is a thermosetting resin, each conductive paste 151F and 152F is cured by heating. The cured product of the first conductive paste 151F corresponds to the first wiring component 151, and the cured product of the second conductive paste 152F corresponds to the second wiring component 152.

[0256] Figure 12 It is a schematic bottom view showing the central part and the ends of the wiring board.

[0257] exist Figure 12 In the diagram, the through holes 116a and 116b before their positions change are shown by double-dotted lines at the ends of the wiring substrate 110.

[0258] Compared to the first wiring layer 113 and the second wiring layer 114, the insulating layer 116 is more prone to deformation, such as shrinkage or expansion, due to changes in the environment, such as temperature or humidity. The deformation of the insulating layer 116 can occur, for example, due to environmental factors such as temperature or humidity during the transport of the wiring substrate 110 from the location where it is manufactured to the location where the planar light source 100 is assembled. Furthermore, the deformation of the insulating layer 116 can occur, for example, during the manufacture of the planar light source 100 due to increased temperature during the curing of the first resin component 133Fa. As indicated by the arrows, due to the deformation of the insulating layer 116, the positions of the two through holes 116a and 116b relative to the two wiring layers 113 and 114 may sometimes change. The effect of this deformation of the insulating layer 116 varies depending on its position in the X and Y directions of the wiring substrate 110.

[0259] Specifically, for example Figure 12As shown, in the central portion of the wiring substrate 110, the deformation of the insulating layer 116 has a smaller impact. The distance E1 between the first through-hole 116a and the first wiring layer 113 in the X direction, and the distance E2 between the second through-hole 116b and the second wiring layer 114 in the X direction, are approximately equal to the design values; for example, distances E1 and E2 are approximately equal. On the other hand, at the ends of the wiring substrate 110, the deformation of the insulating layer 116 has a larger impact, and the two through-holes 116a and 116b are offset in the X direction. As a result, the distance E1 between the first through-hole 116a and the first wiring layer 113 in the X direction, and the distance E2 between the second through-hole 116b and the second wiring layer 114 in the X direction, differ from the design values; for example, distance E1 is longer than distance E2.

[0260] In this configuration, at each location on the wiring substrate 110, the first conductive paste 151F is configured such that the dimension F1 in the X direction of the portion located outside the first through-hole 116a and the third through-hole 119a corresponds to the distance E1. Similarly, at each location on the wiring substrate 110, the second conductive paste 152F is configured such that the dimension F2 in the X direction of the portion located outside the second through-hole 116b and the fourth through-hole 119b corresponds to the distance E2. Therefore, for example, at the central portion of the wiring substrate 110, the dimension F1 of the first wiring member 151 and the dimension F2 of the second wiring member 152 are approximately equal. On the other hand, at the ends of the wiring substrate 110, the dimension F1 of the first wiring member 151 is larger than the dimension F2 of the second wiring member 152.

[0261] Thus, the dimension F1 of each first conductive paste 151F is set to correspond to the distance E1 in the X direction between the corresponding first wiring layer 113 and the first through-hole 116a. Similarly, the dimension F2 of each second conductive paste 152F is set to correspond to the distance E2 in the X direction between the corresponding second wiring layer 114 and the second through-hole 116b. This allows each first electrode 124b to be electrically connected to the first wiring layer 113 one-to-one, and each second electrode 124c to the second wiring layer 114 one-to-one. That is, in the electrical connection structure between the two wiring layers 113, 114 and the two electrodes 124b, 124c, the occurrence of poor connections such as short circuits or open circuits can be suppressed. A short circuit, for example, refers to a state where at least one of the two wiring layers 113, 114 is connected to a wiring component that is not a corresponding wiring component. An open circuit, for example, refers to a state where at least one of the two wiring layers 113, 114 is not connected to any wiring component.

[0262] Additionally, due to the deformation of insulating layer 116, such as Figure 12As shown, the two through holes 116a and 116b may deviate in the Y direction or other directions intersecting the arrangement direction (X direction) of the two through holes 116a and 116b. In contrast, when viewed from above, the two wiring layers 113 and 114 are configured to sandwich the two through holes 116a and 116b. Therefore, even if the two through holes 116a and 116b deviate in any direction, including the arrangement direction of the two through holes 116a and 116b and the direction intersecting the arrangement direction of the two through holes 116a and 116b, it is possible to prevent the first through hole 116a from leaving the first wiring layer 113 and the second through hole 116b from leaving the second wiring layer 114. Furthermore, since no first wiring layer 113 and second wiring layer 114 are disposed between the first through-hole 116a and the second through-hole 116b when viewed from above, it is possible to prevent the first through-hole 116a from approaching the second wiring layer 114 and the second through-hole 116b from approaching the first wiring layer 113. As a result, in the electrical connection structure between the wiring layers 113 and 114 in the wiring substrate 110 and the electrodes 124b and 124c in the light source 120, it is possible to suppress the occurrence of poor connections such as short circuits or open circuits.

[0263] Figure 13A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0264] Figure 13B It is a schematic bottom view illustrating the manufacturing method of a planar light source.

[0265] Next, as Figure 13A as well as Figure 13B As shown, a cover layer 153 is configured to cover the first wiring component 151 and the second wiring component 152.

[0266] Specifically, the cover layer 153 is configured to cover the through hole 115a provided in the second cover layer 115. Thus, the externally exposed portions of the first wiring component 151, the second wiring component 152, the first wiring layer 113, and the second wiring layer 114 are covered by the cover layer 153. Gaps may exist between the cover layer 153 and the first wiring component 151, and between the cover layer 153 and the second wiring component 152. Alternatively, gaps may not exist between the cover layer 153 and the first wiring component 151, and between the cover layer 153 and the second wiring component 152.

[0267] Figure 14 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0268] Figure 15A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0269] Next, as Figure 14 As shown, a light-transmitting second resin component 133Fb is disposed within the light source arrangement section 131 and on the cured product of the first resin component (the first layer 133a of the light-transmitting component 133) and then cured. The second resin component 133Fb may also contain wavelength conversion particles. The cured product of the second resin component 133Fb corresponds to the second layer 133b of the light-transmitting component 133. Thus, a light-transmitting component 133 composed of the first layer 133a and the second layer 133b is formed.

[0270] Next, as Figure 15A As shown, a second light adjustment member 134 is disposed on the light-transmitting member 133, and a dividing member 135 is disposed within the dividing groove 132. The area on the lower surface of the first wiring member 151 directly below the first through hole 116a is flat. Furthermore, the area on the lower surface of the second wiring member 152 directly below the second through hole 116b is flat. Through these methods, a planar light source 100 is formed.

[0271] Figure 15B This is a schematic cross-sectional view showing other examples of the shapes of the first wiring component, the second wiring component, and the cover layer.

[0272] The region 151s on the lower surface of the first wiring component 151, located directly below the first through hole 116a, may also be recessed upwards. Similarly, the region 152s on the lower surface of the second wiring component 152, located directly below the second through hole 116b, may also be recessed upwards. Figure 15B In the example shown, the lower surface of the cover layer 153 is generally flat. However, the area on the lower surface of the cover layer 153 directly below the light source 120 may bulge downwards. In addition, the areas on the lower surface of the cover layer 153 directly below region 151s and directly below region 152s may be recessed upwards along the lower surfaces of the wiring components 151 and 152.

[0273] For example, when each conductive paste 151F and 152F is cured, the solvent and other diluents contained in each conductive paste 151F and 152F are released to form wiring components 151 and 152 with the above-described shapes.

[0274] Figure 15C This is a schematic cross-sectional view showing other examples of the shapes of the first wiring component, the second wiring component, and the cover layer.

[0275] The region 151s on the lower surface of the first wiring component 151, located directly below the first through hole 116a, may also bulge downwards. Similarly, the region 152s on the lower surface of the second wiring component 152, located directly below the second through hole 116b, may also bulge downwards. Figure 15C In the example shown, the lower surface of the cover layer 153 is generally flat. However, the area directly below the light source 120 on the lower surface of the cover layer 153 may also bulge downwards. In addition, the areas directly below region 151s and directly below region 152s on the lower surface of the cover layer 153 may also bulge downwards along the lower surfaces of the wiring components 151 and 152.

[0276] For example, using a distributor, the conductive pastes 151F and 152F are arranged such that the portions directly above the through holes 116a and 116b are bulging upwards, thereby forming wiring components 151 and 152 with the aforementioned shape. Alternatively, the conductive pastes 151F and 152F are printed multiple times, for example, such that the portions directly above the through holes 116a and 116b are bulging upwards, thereby forming wiring components 151 and 152 with the aforementioned shape.

[0277] When regions 151s and 152s are flat or bulging downwards, a force is easily applied that presses each wiring component 151 and 152 against the wiring substrate 110. Therefore, each wiring component 151 and 152 can be securely fixed to the wiring substrate 110.

[0278] Furthermore, when the planar light source 100 is driven, its temperature rises and falls depending on whether each light source 120 is lit or not. As a result, the wiring substrate 110, sheet laminate 119, light guide member 130, and wiring members 151 and 152 constituting the planar light source 100 may deform. Since their coefficients of thermal expansion differ, there is a possibility of stress being applied to the wiring members 151 and 152, causing cracks. In this embodiment, as described above, by securely fixing each wiring member 151 and 152 to the wiring substrate 110, the stress acting on the wiring members 151 and 152 can be mitigated. As a result, cracking in the wiring members 151 and 152 can be suppressed.

[0279] The material of the light-reflective sheet 117 is preferably a material with a lower coefficient of thermal expansion than that of the light guide component 130. Furthermore, the material of the light-reflective sheet 117 is preferably a material with a higher coefficient of thermal expansion than that of the wiring substrate 110. This mitigates the difference in coefficients of thermal expansion between the light guide component 130 and the wiring substrate 110. If the light guide component 130 is polycarbonate, the coefficient of thermal expansion is approximately 60 ppm / °C. If the main component of the light-reflective sheet 117 is polyethylene terephthalate, the coefficient of thermal expansion is approximately 25 ppm / °C. When the wiring substrate 110 contains polyimide and copper, the coefficient of thermal expansion is approximately 17 ppm / °C.

[0280] The above methods can improve the intensity of the planar light source 100.

[0281] However, the manufacturing method of the planar light source is not limited to the above. For example, it is also possible to fill the light source arrangement section with a first resin component for temporarily fixing the light source within the light source arrangement section without configuring a second resin component. Furthermore, the first resin component for temporarily fixing the light source within the light source arrangement section may not be configured before configuring the conductive pastes. Additionally, the steps of forming the dividing groove and configuring the second light adjustment component and the dividing component may be performed before the steps of forming the first wiring component and the second wiring component. Furthermore, the step of configuring the light guide component may be performed after the step of configuring the light source.

[0282] Next, the operation of the planar light source 100 in this embodiment will be explained.

[0283] The first wiring layer 113 is electrically connected to the first electrode 124b of the light source 120 via the first wiring component 151 and the first terminal 122, and the second wiring layer 114 is electrically connected to the second electrode 124c of the light source 120 via the second wiring component 152 and the second terminal 123. Therefore, by supplying power to the light source 120 from an external power source via the first wiring layer 113 and the second wiring layer 114, the light source 120 can be lit.

[0284] The planar light source 100 can be used, for example, as a backlight for a liquid crystal display. In a backlight in which each of the plurality of light sources 120 is divided into a light-emitting area R, local dimming can be performed with high precision by adjusting the output of each light source 120 separately.

[0285] Next, the effects of this implementation method will be explained.

[0286] The planar light source 100 of this embodiment includes a wiring substrate 110, a light source 120, a light guide component 130, a first wiring component 151, and a second wiring component 152. The wiring substrate 110 has: an insulating layer 116 having mutually spaced first through-holes 116a and second through-holes 116b; a first wiring layer 113 and a second wiring layer 114 disposed below the insulating layer 116 and separated from the first through-holes 116a and second through-holes 116b. The light source 120 is disposed on the wiring substrate 110 and has mutually spaced first electrodes 124b and second electrodes 124c. The light guide component 130 is disposed on the wiring substrate 110, surrounding the light source 120. The first wiring component 151 has a first portion 151a and a second portion 151b. The first portion 151a fills the first through-hole 116a and is electrically connected to the first electrode 124b. The second portion 151b is disposed below the insulating layer 116, connected to the first portion 151a, and connected to the first wiring layer 113. The second wiring component 152 has a third portion 152a and a fourth portion 152b. The third portion 152a fills the second through-hole 116b and is electrically connected to the second electrode 124c. The fourth portion 152b is disposed below the insulating layer 116, connected to the third portion 152a, and connected to the second wiring layer 114. In top view, the first wiring layer 113 and the second wiring layer 114 are configured to sandwich the first through-hole 116a and the second through-hole 116b.

[0287] Thus, the mutually separated first through-hole 116a and the first wiring layer 113 are electrically connected by a first wiring component 151 arranged according to the positions of the first through-hole 116a and the first wiring layer 113, and the mutually separated second through-hole 116b and the second wiring layer 114 are electrically connected by a second wiring component 152 arranged according to the positions of the second through-hole 116b and the second wiring layer 114. Moreover, in top view, the first wiring layer 113 and the second wiring layer 114 are configured to sandwich the first through-hole 116a and the second through-hole 116b. That is, in top view, the first through-hole 116a and the second through-hole 116b are arranged between the first wiring layer 113 and the second wiring layer 114, while on the other hand, the first wiring layer 113 and the second wiring layer 114 are not arranged between the first through-hole 116a and the second through-hole 116b. Therefore, when forming each wiring component 151, 152, even if the through holes 116a, 116b are offset from the wiring layers 113, 114, the generation of poor connections such as short circuits or open circuits can be suppressed in the electrical connection structure between the wiring layers 113, 114 in the wiring substrate 110 and the electrodes 124b, 124c in the light source 120.

[0288] Furthermore, when viewed from above, the distance D1 between the center c1 of the first through hole 116a and the center c2 of the second through hole 116b is longer than the distance D2 between the center c3 of the first electrode 124b and the center c4 of the second electrode 124c (D1 > D2). Therefore, even if the insulating layer 116 deforms during the manufacturing of the planar light source 100, it is possible to prevent the first wiring component 151 from approaching or contacting the second wiring component 152.

[0289] In addition, the area (first region 113s1) of the side surface 113e of the first wiring layer 113 opposite to the first through hole 116a when viewed from above is concave in the direction away from the first through hole 116a, and the area (first region 114s1) of the side surface 114e of the second wiring layer 114 opposite to the second through hole 116b when viewed from above is concave in the direction away from the second through hole 116b.

[0290] Therefore, compared to the case where the shapes of regions 113s1 and 114s1 are straight lines when viewed from above, as... Figure 4A As shown, the maximum value of the distance D3 between each position of the first region 113s1 and the center c1 of the first part 151a when viewed from above, and the maximum value of the distance D4 between each position of the first region 114s1 and the center c2 of the third part 152a when viewed from above, can be reduced. As a result, the internal resistance of the first wiring component 151 and the second wiring component 152 can be reduced.

[0291] Furthermore, the shapes of the first through-hole 116a and the second through-hole 116b, when viewed from above, are circular. The shapes of the area (first region 113s1) on the side 113e of the first wiring layer 113, which faces the first through-hole 116a when viewed from above, and the area (first region 114s1) on the side 114e of the second wiring layer 114, which faces the second through-hole 116b when viewed from above, are arc-shaped. By setting the first region 113s1 of the first wiring layer 113 to correspond to the shape of the first through-hole 116a, the distance D3 between each position of the first region 113s1 and the center c1 of the first part 151a when viewed from above can be approximately constant. The same applies to the second wiring layer 114. As a result, the internal resistance of the first wiring component 151 and the second wiring component 152 can be reduced.

[0292] Furthermore, the light source 120 also includes: a first terminal 122 disposed below the first electrode 124b and connected to the upper end of the first portion 151a, with an area exceeding the area of ​​the first electrode 124b when viewed from above; and a second terminal 123 disposed below the second electrode 124c and connected to the upper end of the third portion 152a, with an area exceeding the area of ​​the second electrode 124c when viewed from above. Therefore, a first through hole 116a and a second through hole 116b, spaced apart from each other, can be provided according to the positions of the first terminal 122 and the second terminal 123.

[0293] Furthermore, the first terminal 122 covers the first through hole 116a when viewed from above, and the second terminal 123 covers the second through hole 116b when viewed from above. Therefore, the contact area between each terminal 122, 123 and each wiring component 151, 152 can be increased. This ensures a stable connection between each terminal 122, 123 and each wiring component 151, 152.

[0294] In addition, the planar light source 100 also includes a cover layer 153 that covers the first wiring component 151 and the second wiring component 152. Therefore, it is possible to suppress the exposure of each wiring component 151, 152 to the outside.

[0295] Furthermore, the first wiring component 151 and the second wiring component 152 each have a base material made of resin material and at least one metal particle disposed in the base material. Thus, each wiring component 151, 152 is made of conductive paste 151F, 152F. Therefore, even if the relative positions of the two through holes 116a, 116b and the two wiring layers 113, 114 change due to deformation of the insulating layer 116 during the manufacturing of the planar light source 100, the first wiring component 151 and the second wiring component 152 corresponding to the relative positions of the two through holes 116a, 116b and the two wiring layers 113, 114 can be easily formed using the conductive paste 151F, 152F.

[0296] Furthermore, the manufacturing method of the planar light source 100 in this embodiment includes: a step of preparing a wiring substrate 110, which has an insulating layer 116 having a first through hole 116a and a second through hole 116b that are separated from each other, and a first wiring layer 113 and a second wiring layer 114 disposed below the insulating layer 116 and separated from the first through hole 116a and the second through hole 116b, and configured such that the first wiring layer 113 and the second wiring layer 114 sandwich the first through hole 116a and the second through hole 116b when viewed from above; and a wiring substrate 110 is disposed on the wiring substrate 110. The process includes a light guide component 130 having a light source configuration section 131 for configuring the light source 120; a process of configuring the light source 120 on a wiring substrate 110; and a process of forming a first wiring component 151 and a second wiring component 152, wherein the first wiring component 151 fills a first through hole 116a, is connected to a first wiring layer 113, and is electrically connected to a first electrode 124b of the light source 120, and the second wiring component 152 is separated from the first wiring component 151, fills a second through hole 116b, is connected to a second wiring layer 114, and is electrically connected to a second electrode 124c of the light source 120.

[0297] Thus, even if the positions of the two through holes 116a and 116b relative to the two wiring layers 113 and 114 change due to deformation of the insulating layer 116 during the manufacturing of the planar light source 100, wiring components 151 and 152 are formed corresponding to the positions of the two wiring layers 113 and 114 and the two through holes 116a and 116b. Furthermore, in top view, the first wiring layer 113 and the second wiring layer 114 are configured to sandwich the first through hole 116a and the second through hole 116b. Therefore, even if the positions of the through holes 116a and 116b relative to the wiring layers 113 and 114 deviate during the formation of each wiring component 151 and 152, poor connections such as short circuits or open circuits can be suppressed in the electrical connection structure between the wiring layers 113 and 114 in the wiring substrate 110 and the electrodes 124b and 124c in the light source 120.

[0298] Furthermore, the process of forming the first wiring component 151 and the second wiring component 152 includes: distributing a first conductive paste 151F to fill the first through-hole 116a and connect it to the first wiring layer 113, distributing a second conductive paste 152F to fill the second through-hole 116b and connect it to the second wiring layer 114; and curing the first conductive paste 151F and the second conductive paste 152F. Thus, the conductive pastes 151F and 152F are disposed according to the distance between each through-hole 116a, 116b in the wiring substrate 110 and each wiring layer 113, 114. Therefore, even if the relative positions of the two through-holes 116a, 116b and the two wiring layers 113, 114 change due to deformation of the insulating layer 116, the two wiring layers 113, 114 can still be connected one-to-one with the two electrodes 124b, 124c. As a result, in the electrical connection structure between the wiring layers 113 and 114 in the wiring substrate 110 and the electrodes 124b and 124c in the light source 120, the generation of poor connection can be suppressed.

[0299] Furthermore, the manufacturing method of the planar light source 100 in this embodiment also includes a step of placing a light-transmitting resin component (first resin component 133Fa) in the light source placement section 131 and in the gap between the light guide component 130 and the light source 120 after the step of arranging the light guide component 130 and the light source 120, and before the step of forming the first wiring component 151 and the second wiring component 152. Therefore, by using the resin component (first resin component 133Fa), leakage of each conductive paste 151F and 152F in the light source placement section 131 can be suppressed.

[0300] Furthermore, the light source 120 also has a first terminal 122 disposed below the first electrode 124b and a second terminal 123 disposed below the second electrode 124c. The light source 120 is configured such that, when viewed from above, the first terminal 122 covers the first through-hole 116a and the second terminal 123 covers the second through-hole 116b. Therefore, leakage of each conductive paste 151F and 152F from the openings of each through-hole 116a and 116b on the light source 120 side can be suppressed.

[0301] <Second Implementation>

[0302] Next, the second embodiment will be described.

[0303] Figure 16 This is a schematic cross-sectional view showing a portion of the planar light source of this embodiment, enlarged.

[0304] The planar light source 200 of this embodiment differs from the planar light source 100 of the first embodiment in the shape of the peripheral portion 212a of the first through hole 216a and the peripheral portion 212b of the second through hole 216b in the insulating layer 216, as well as the shape of the peripheral portion 219c of the third through hole 219a and the peripheral portion 219d of the fourth through hole 219b in the sheet laminate 219. This will be described in detail below.

[0305] Furthermore, in the following description, only the differences from the first embodiment will be explained in principle. Except for the matters described below, everything is the same as the first embodiment. The same applies to the other embodiments described later.

[0306] The wiring substrate 210 has a base layer 211, a first cover layer 212 disposed on the base layer 211, a first wiring layer 213 disposed below the base layer 211, a second wiring layer 214 disposed below the base layer 211, and a second cover layer 215 disposed below the base layer 211. The base layer 211 and the first cover layer 212 correspond to an insulating layer 216.

[0307] The insulating layer 216 has a first peripheral portion 212a surrounding the first through hole 216a, a second peripheral portion 212b surrounding the second through hole 216b, and a flat portion 212c located around the first peripheral portion 212a and the second peripheral portion 212b and substantially parallel to the X and Y directions.

[0308] The upper and lower surfaces of the first peripheral portion 212a are bent downwards. Similarly, the upper and lower surfaces of the second peripheral portion 212b are bent downwards. By bending the upper surfaces of the first peripheral portion 212a and the second peripheral portion 212b downwards, the conductive pastes 151F and 152F filling the third through hole 219a and the fourth through hole 219b are widened in cross-section, thereby increasing the connection area between the light-emitting element and the conductive pastes 151F and 152F.

[0309] The sheet laminate 219 has a light-reflective sheet 217 and two adhesive sheets 218a and 218b.

[0310] The sheet laminate 219 has a first peripheral portion 219c surrounding the third through hole 219a, a second peripheral portion 219d surrounding the fourth through hole 219b, and a flat portion 219e located around the first peripheral portion 219c and the second peripheral portion 219d and substantially parallel to the X and Y directions.

[0311] The upper and lower surfaces of the first peripheral portion 219c are curved downwards as they approach the center of the third through hole 219a. Similarly, the upper and lower surfaces of the second peripheral portion 219d are curved downwards as they approach the center of the fourth through hole 219b. In other words, the first peripheral portion 219c and the second peripheral portion 219d are embedded in the insulating layer 216.

[0312] The first peripheral portion 219c is separated from the first terminal 122. Similarly, the second peripheral portion 219d is separated from the second terminal 123. The flat portion 219e is in contact with the outer periphery of the lower surface of the first terminal 122 and the outer periphery of the lower surface of the second terminal 123 in the light source 120. Therefore, a first gap S1 is provided between the first peripheral portion 219c and the first terminal 122, and a second gap S2 is provided between the second peripheral portion 219d and the second terminal 123.

[0313] A portion of the first wiring component 251 is disposed within the first gap S1, for example, filling the first gap S1. Similarly, a portion of the second wiring component 252 is disposed within the second gap S2, for example, filling the second gap S2. Therefore, the contact area between the first wiring component 251 and the first terminal 122, and the contact area between the second wiring component 252 and the second terminal 123, can be increased. Consequently, the connection between the first wiring component 251 and the first terminal 122, and the connection between the second wiring component 252 and the second terminal 123, can be made more secure.

[0314] Next, the manufacturing method of the planar light source 200 of this embodiment will be described.

[0315] Figure 17 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0316] Figure 18 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0317] Figure 19 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0318] Figure 20 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0319] First, such as Figure 17 As shown, a sheet laminate 219 is disposed on the wiring substrate 210.

[0320] Next, as Figure 18As shown, the drill bit 900 is moved from the upper surface of the sheet laminate 219 toward the lower surface of the insulating layer 216, causing the drill bit 900 to penetrate through the sheet laminate 219 and the insulating layer 216. This forms a first through hole 216a and a second through hole 216b in the wiring substrate 210, and a third through hole 219a and a fourth through hole 219b in the sheet laminate 219. At this time, depending on the processing conditions or the hardness of the sheet laminate 119 and the insulating layer 216, the portion of the sheet laminate 219 in contact with the drill bit 900 is pressed into the insulating layer 216 due to the downward movement of the drill bit 900. As a result, a first peripheral portion 219c and a second peripheral portion 219d embedded in the insulating layer 216 are formed in the sheet laminate 219.

[0321] Next, a light guide member 130 with a light source configuration section 131 is disposed on the wiring substrate 210 and the sheet laminate 219.

[0322] Next, a dividing groove 132 is formed on the light guide component 130.

[0323] Next, a light source 120 is arranged in the light source arrangement section 131. The light source 120 is arranged such that the outer periphery of the first terminal 122 and the outer periphery of the second terminal 123 are in contact with the flat portion 219e of the sheet laminate 219.

[0324] Next, the first resin component 133Fa is placed inside the light source mounting section 131 and cured.

[0325] Next, as Figure 19 As shown, a first conductive paste 251F is filled in the first through-hole 216a, the third through-hole 219a, and the first gap S1, and is configured to be in contact with the lower surface of the insulating layer 216 and the first wiring layer 213. Additionally, a second conductive paste 252F is filled in the second through-hole 216b, the fourth through-hole 219b, and the second gap S2, and is configured to be in contact with the lower surface of the insulating layer 216 and the second wiring layer 214.

[0326] Next, as Figure 20 As shown, the first conductive paste 251F and the second conductive paste 252F are cured. The cured product of the first conductive paste 251F corresponds to the first wiring component 251, and the cured product of the second conductive paste 252F corresponds to the second wiring component 252.

[0327] The subsequent steps are the same as the manufacturing method of the planar light source 100 in the first embodiment, so the description is omitted.

[0328] <Third Implementation Method>

[0329] Next, the planar light source of the third embodiment will be described.

[0330] Figure 21 This is an enlarged schematic top view showing a portion of the wiring substrate, a portion of the sheet laminate, and the light source of the planar light source according to this embodiment.

[0331] The planar light source 300 of this embodiment differs from the planar light source 100 of the first embodiment in the shape of the two electrodes 324b, 324c and the two terminals 322, 323 in the light source 320. This will be described in detail below.

[0332] The light source 320 has a main body 321, a first terminal 322, and a second terminal 323. The first electrode 324b, viewed from above, is a rectangle with two parallel long sides and two parallel short sides. Viewed from above, each long side of the first electrode 324b is parallel to two of the four parallel sides of the main body 321. Viewed from above, each short side of the first electrode 324b is orthogonal to each long side of the first electrode 324b.

[0333] The shape of the second electrode 324c when viewed from above is symmetrical to the first electrode 324b, with reference to axis L3 which passes through the center of the main body 321 and is parallel to the two long sides of the first electrode 324b.

[0334] Viewed from above, the first terminal 322 is a rectangle with two parallel long sides and two parallel short sides. Viewed from above, the long sides of the first terminal 322 are approximately parallel to the two long sides of the first electrode 324b. Viewed from above, the short sides of the first terminal 322 are orthogonal to the long sides of the first terminal 322.

[0335] The second terminal 323, when viewed from above, has the shape of a rectangle that is symmetrical to the first terminal 322, cut off with reference to axis L3.

[0336] When viewed from above, the area of ​​the first terminal 322 is larger than the area of ​​the first electrode 324b, and the area of ​​the second terminal 323 is larger than the area of ​​the second electrode 324c.

[0337] When viewed from above, the first terminal 322 covers the first through hole 116a, and the second terminal 323 covers the second through hole 116b.

[0338] As explained above, the shapes of the first electrode 324b and the second electrode 324c when viewed from above can also be rectangular. Additionally, the shapes of the first terminal 322 and the second terminal 323 when viewed from above can also be rectangular.

[0339] <Fourth Implementation>

[0340] Next, the fourth embodiment will be described.

[0341] Figure 22 This is a schematic cross-sectional view showing the planar light source of this embodiment.

[0342] The configuration of the first wiring component 451 and the second wiring component 452 of the planar light source 400 in this embodiment differs from that of the planar light source 100 in the first embodiment. This will be described in detail below.

[0343] The first wiring component 451 has a first portion 451a that fills the first through hole 116a and the third through hole 119a and is connected to the first terminal 122, and a thin film-shaped second portion 451b that is connected to the first portion 451a and is connected to the lower surface of the insulating layer 116 and the first wiring layer 113.

[0344] The second wiring component 452 has a third portion 452a that fills the second through hole 116b and the fourth through hole 119b and is connected to the second terminal 123, and a thin film-shaped fourth portion 452b that is connected to the third portion 452a and is connected to the lower surface of the insulating layer 116 and the second wiring layer 114.

[0345] The resin material constituting the first part 451a is the same as the resin material constituting the third part 452a, and the metal particles constituting the first part 451a are the same as the metal particles constituting the third part 452a. The resin material constituting the second part 451b is the same as the resin material constituting the fourth part 452b, and the metal particles constituting the second part 451b are the same as the metal particles constituting the fourth part 452b.

[0346] On the other hand, the resin material constituting the first part 451a is different from the resin material constituting the second part 451b. Furthermore, the metal particles constituting the first part 451a are different from the metal particles constituting the second part 451b. However, it is also possible that at least one of the resin material or the metal particles is the same. Thus, by making the material constituting the first part 451a of the first wiring member 451 different from the material constituting the second part 451b, it is possible to make the mechanical properties such as flexibility or the electrical properties such as conductivity of the first part 451a and the second part 451b different. The same applies to the second wiring member 452.

[0347] Next, the manufacturing method of the planar light source 400 of this embodiment will be described.

[0348] Figure 23 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0349] Figure 24 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0350] Figure 25 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0351] After the first resin component 133Fa is disposed in the light source configuration section 131 and cured, as follows: Figure 23 As shown, a first conductive paste 451Fa is filled in the first through hole 116a and the third through hole 119a, and a second conductive paste 452Fa is filled in the second through hole 116b and the fourth through hole 119b. Each conductive paste 451Fa and 452Fa is composed of the same material as the conductive pastes 151F and 152F in the first embodiment, comprising uncured resin material and one or more metal particles dispersed in the resin material. It is also anticipated that each conductive paste 451Fa and 452Fa will shrink during curing, thus positioning each conductive paste 451Fa and 452Fa to protrude from each through hole 116a and 116b.

[0352] Next, as Figure 24 As shown, the first conductive paste 451Fa and the second conductive paste 452Fa are cured. The cured product of the first conductive paste 451Fa corresponds to the first portion 451a of the first wiring component 451, and the cured product of the second conductive paste 452Fa corresponds to the third portion 452a of the second wiring component 452.

[0353] Next, the third conductive paste 451Fb is configured to be in contact with the insulating layer 116, the cured product of the first conductive paste 451Fa (i.e., the first portion 451a), and the first wiring layer 113, and the fourth conductive paste 452Fb is configured to be in contact with the insulating layer 116, the cured product of the second conductive paste 452Fa (i.e., the third portion 452a), and the second wiring layer 114.

[0354] Next, as Figure 25 As shown, the third conductive paste 451Fb and the fourth conductive paste 452Fb are cured. The cured third conductive paste 451Fb corresponds to the second portion 451b of the first wiring component 451, and the cured fourth conductive paste 452Fb corresponds to the fourth portion 452b of the second wiring component 452.

[0355] The subsequent steps are the same as the manufacturing method of the planar light source 100 in the first embodiment, so the description is omitted.

[0356] As explained above, in the manufacturing method of the planar light source 400 of this embodiment, the steps for forming the first wiring component 451 and the second wiring component 452 include: filling a first conductive paste 451Fa into a first through hole 116a and filling a second conductive paste 452Fa into a second through hole 116b; curing the first conductive paste 451Fa and the second conductive paste 452Fa; configuring a third conductive paste 451Fb to be in contact with the cured first conductive paste 451Fa and the first wiring layer 113, and configuring a fourth conductive paste 452Fb to be in contact with the cured second conductive paste 452Fa and the second wiring layer 114; and curing the third conductive paste 451Fb and the fourth conductive paste 452Fb. Thus, the first portion 451a and the second portion 451b of the first wiring component 451 may not be formed simultaneously. Alternatively, the third portion 452a and the fourth portion 452b of the second wiring component 452 may not be formed simultaneously. According to this method, the materials of the first conductive paste 451Fa and the second conductive paste 452Fa can be different from the materials of the third conductive paste 451Fb and the fourth conductive paste 452Fb.

[0357] Alternatively, a third and fourth conductive paste can be prepared before the first and second conductive pastes are cured. That is, the process of forming the first wiring component and the second wiring component may include: filling the first through-hole with the first conductive paste and filling the second through-hole with the second conductive paste; configuring the third conductive paste to be in contact with the first conductive paste and the first wiring layer and configuring the fourth conductive paste to be in contact with the second conductive paste and the second wiring layer; and a process of curing the first, second, third, and fourth conductive pastes.

[0358] <Fifth Implementation>

[0359] Next, the fifth embodiment will be described.

[0360] Figure 26 This is a schematic cross-sectional view illustrating the manufacturing method of the planar light source according to the fifth embodiment.

[0361] The manufacturing method of the planar light source in this embodiment differs from the manufacturing method of the planar light source 100 in the first embodiment in terms of the shape of the cured first resin component 533Fa that strengthens the temporary fixation of the light source 120 to the wiring substrate 110. This will be described in detail below.

[0362] After the sheet laminate 119, the light guide component 130, and the light source 120 are disposed on the wiring substrate 110, a light-transmitting first resin component 533Fa is disposed on the side of the light source placement portion 131 and in the gap between the light source 120 and the light source 120 and then cured to strengthen the temporary fixation of the light source 120 to the wiring substrate 110 based on the adhesive sheet 118b.

[0363] In this embodiment, the light-transmitting first resin component 533Fa is configured to seal the light source 120, and its upper surface is located below the upper surface of the light guide component 130. The cured product of the first resin component 533Fa corresponds to the first layer of the light-transmitting component. Furthermore, on the upper surface of the first resin component 533Fa, a region 533Fc located between the side of the light source arrangement portion 131 and the light source 120 is recessed downwards. A portion of region 533Fc is located below the upper surface of the light source 120.

[0364] Next, as in the first embodiment, the conductive pastes 151F and 152F are configured. At this time, the gap between the side of the light source configuration section 131 and the light source 120 is sealed by the first resin component 533Fa. Therefore, leakage of the conductive pastes 151F and 152F into the light source configuration section 131 can be suppressed. The subsequent sequence is the same as that of the planar light source 100 in the first embodiment, so its description is omitted.

[0365] <Sixth Implementation Method>

[0366] Next, the sixth embodiment will be described.

[0367] Figure 27 This is a schematic cross-sectional view showing the planar light source of this embodiment.

[0368] The planar light source 600 of this embodiment differs from the planar light source 100 of the first embodiment in the configuration of the light source 620 and the light guide component 630.

[0369] The light source 620 has a light-emitting element 621, a wavelength conversion component 622, a light-transmitting component 623, and a cover layer 624.

[0370] The light-emitting element 621 has a light-emitting portion 621a, a first electrode 621b disposed below the light-emitting portion 621a and separated from each other, and a second electrode 621c. A wavelength conversion component 622 is provided on the light-emitting element 621.

[0371] The light-transmitting component 623 is disposed below the wavelength conversion component 622 and around the light-emitting part 621a. The cover layer 624 is disposed around the light-transmitting component 623 and below the light-emitting part 621a. The outer surface of the light-transmitting component 623 may also be an inclined surface.

[0372] The light guide member 630 is provided with a light source configuration section 631 for configuring the light source 620. In this embodiment, the light source configuration section 631 is a recess provided on the lower surface of the light guide member 630.

[0373] Furthermore, the light guide component 630 is provided with dividing grooves 632 in a manner that surrounds each light source 620. In this embodiment, the dividing grooves 632 are recesses provided on the lower surface of the light guide component 630.

[0374] A dividing member 633 is provided on the lower surface of the light guide member 630 and within the dividing groove 632. The dividing member 633 has a through hole 633a communicating with the light source arrangement portion 631 of the light guide member 630. A light-transmitting member 634 is provided in both the light source arrangement portion 631 and the through hole 633a. The dividing member 633 is adhered to the wiring substrate 110 using an adhesive sheet 618.

[0375] The adhesive sheet 618 has a third through hole 618a and a fourth through hole 618b. The third through hole 618a is located directly above the first through hole 116a. The fourth through hole 618b is located directly above the second through hole 116b.

[0376] In addition, a plurality of recesses 635 are provided on the upper surface of the light guide component 630. Each recess 635 is located directly above each light source 620. A light adjustment component 636 is provided in each recess 635.

[0377] Next, the manufacturing method of the planar light source 600 of this embodiment will be described.

[0378] Figure 28 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0379] Figure 29 It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0380] First, such as Figure 28 As shown, a wiring substrate 110 is prepared.

[0381] Next, a light guide component 630 and a light source 620 are disposed on the wiring substrate 110. In this embodiment, the light source 620, light guide component 630, dividing component 633, light-transmitting component 634, and light-adjusting component 636 are pre-integrated into a light-emitting module before being disposed on the wiring substrate 110, and are adhered to the wiring substrate 110 using an adhesive sheet 618. However, the light-adjusting component 636 may also be disposed on the light guide component 630 after the light source 620 and light guide component 630 are disposed on the wiring substrate 110.

[0382] Next, as Figure 29As shown, the first conductive paste 151F is configured to fill the first through-hole 116a and the third through-hole 618a, and is in contact with the insulating layer 116 and the first wiring layer 113. Additionally, the second conductive paste 152F is configured to fill the second through-hole 116b and the fourth through-hole 618b, and is in contact with the insulating layer 116 and the second wiring layer 114.

[0383] The subsequent sequence is the same as the manufacturing method of the planar light source 100 in the first embodiment, so its description is omitted.

[0384] As explained above, the light source arrangement part 631 can also be a recess provided on the lower surface of the light guide member 630. In addition, when manufacturing the planar light source 600, the light source 620 and the light guide member 630 can be integrated and disposed on the wiring substrate 110.

[0385] Furthermore, although this embodiment illustrates an example where the light source 620 does not have a first terminal and a second terminal, the light source 620 may also have a first terminal and a second terminal.

[0386] Furthermore, in this embodiment, the first through-hole 116a and the second through-hole 116b of the wiring substrate 110 are described as being located below the light source 620, but this is not a limitation. That is, the first through-hole 116a and the second through-hole 116b of the wiring substrate 110 do not need to be located below the light source 620. In this case, a conductive layer electrically connected to each electrode 621a, 621b of the light source may be provided on the upper surface of the wiring substrate 110 or the lower surface of the dividing member 633, and the conductive layer may be connected to the first wiring member 151 and the second wiring member 152.

[0387] <Seventh Implementation>

[0388] Next, the seventh embodiment will be described.

[0389] Figure 30 This is a schematic bottom view showing the light source and a portion of the wiring substrate in the planar light source of this embodiment, enlarged.

[0390] Figure 31A yes Figure 30 A schematic cross-sectional view of the XXXI-XXXI line.

[0391] The wiring substrate 710 of the planar light source 700 in this embodiment has a different structure than that of the planar light source 100 in the first embodiment.

[0392] Wiring board 710, such as Figure 30 as well as Figure 31AAs shown, it has a base layer 711, a first cover layer 712 disposed on the base layer 711, a first wiring layer 713 and a second wiring layer 714 disposed below the base layer 711, and a second cover layer 715 disposed below the base layer 711. The base layer 711 and the first cover layer 712 correspond to an insulating layer 716.

[0393] The insulating layer 716 has a first through hole 716a and a second through hole 716b that are separated from each other. Each through hole 716a and 716b penetrates the insulating layer 716 along the Z direction.

[0394] The first wiring layer 713 and the second wiring layer 714 are as follows Figure 30 As shown, the wiring layers 713 and 714 are not configured to sandwich the first through-hole 716a and the second through-hole 716b, but are separated from the first through-hole 716a and the second through-hole 716b in the Y direction. Each wiring layer 713, 714 extends along the Y direction in this embodiment. The distance D5 between the front end portion 713a of the first wiring layer 713 and the front end portion 714a of the second wiring layer 714 is longer than the distance D6 between the first through-hole 716a and the second through-hole 716b. However, the relationship between the distance between the front end portion of the first wiring layer and the front end portion of the second wiring layer and the distance between the first through-hole and the second through-hole is not limited to the above.

[0395] The second cover layer 715 covers the area surrounding the first through-hole 716a and the second through-hole 716b in the lower surface of the insulating layer 716 in such a way that the first through-hole 716a and the second through-hole 716b are exposed. Additionally, the second cover layer 715 exposes a portion of the first wiring layer 713 and the second wiring layer 714.

[0396] Specifically, the second cover layer 715 has a first opening 715a that exposes the first through hole 716a and a second opening 715b that exposes the second through hole 716b. The first opening 715a is located directly below the first through hole 716a. The second opening 715b is located directly below the second through hole 716b. When viewed from above, the shapes of the first opening 715a and the second opening 715b are approximately the same as those of the first through hole 716a and the second through hole 716b, for example, they are circles, triangles, or other polygons. However, the shapes of the first opening and the second opening when viewed from above are not limited to the above. The opening diameter of the first opening 715a is as follows: Figure 30 , Figure 31A As shown, the opening diameter is the same as that of the first through hole 716a. Similarly, the opening diameter of the second opening 715b is as shown... Figure 30 , Figure 31A As shown, it is consistent with the opening diameter of the second through hole 716b.

[0397] Additionally, the second cover layer 715 has a third opening 715c that exposes the front end portion 713a of the first wiring layer 713 and a fourth opening 715d that exposes the front end portion 713b of the second wiring layer 714. When viewed from above, each opening 715c and 715d is circular. However, the shapes of the third and fourth openings when viewed from above can also be polygonal, such as semicircles or rectangles. Alternatively, a single opening can be used to expose a portion of both the first and second wiring layers.

[0398] The third opening 715c and the fourth opening 715d are separated from the first opening 715a and the second opening 715b. The distance D7 between the third opening 715c and the fourth opening 715d is longer than the distance D6 between the first through hole 716a and the second through hole 716b. However, the relationship between the distance between the third and fourth openings and the distance between the first and second through holes is not limited to the above.

[0399] First wiring component 751, such as Figure 31A As shown, it has: a first portion 751a that fills the first through hole 716a, the third through hole 119a, and the first opening 715a; and a second portion 751b that is connected to the portion of the first wiring layer 713 exposed from the second cover layer 715 via the lower surface of the second cover layer 715.

[0400] The first portion 751a is connected to the first terminal 122 and is electrically connected to the first electrode 124b via the first terminal 122. In this embodiment, the second portion 751b is connected to the front end portion 713a of the first wiring layer 713.

[0401] The second wiring component 752 has: a third portion 752a that fills the second through hole 716b, the fourth through hole 119b, and the second opening 715b; and a fourth portion 752b that is connected to the portion of the second wiring layer 714 exposed from the second cover layer 715 via the lower surface of the second cover layer 715.

[0402] The third part 752a is connected to the second terminal 123 and is electrically connected to the second electrode 124c via the second terminal 123. The fourth part 752b is connected to the front end 714a of the second wiring layer 714 in this embodiment.

[0403] In addition, the planar light source 700 may also include a cover layer that covers the portions of the first wiring component 751, the second wiring component 752, the first wiring layer 713, and the second wiring layer 714 that are exposed from the second cover layer 715.

[0404] Furthermore, in this embodiment, the third opening 715c and the fourth opening 715d are as follows: Figure 30As shown, the third opening 715c and the fourth opening 715d are located on the -Y direction side compared to the first opening 715a and the second opening 715b, but are not limited to this. For example, the third opening 715c and the fourth opening 715d may also be located on the +Y direction side compared to the first opening 715a and the second opening 715b. Alternatively, the third opening 715c may be located on the -Y direction side compared to the first opening 715a and the second opening 715b, and the fourth opening 715d may be located on the +Y direction side compared to the first opening 715a and the second opening 715b. Conversely, the fourth opening 715d may be located on the -Y direction side compared to the first opening 715a and the second opening 715b, and the third opening 715c may be located on the +Y direction side compared to the first opening 715a and the second opening 715b. Additionally, the third opening 715c and the fourth opening 715d may be configured to sandwich the first opening 715a and the second opening 715b on a virtual line passing through them.

[0405] Figure 31B This is a schematic bottom view showing other examples of light sources and wiring substrates.

[0406] like Figure 31B As shown, the light source 120 can also be configured with two electrodes 124b and 124c arranged in directions intersecting the X and Y directions. In this case, the third opening 715c may be located on the +Y direction side compared to the first opening 715a and the second opening 715b, and the fourth opening 715d may be located on the -Y direction side compared to the first opening 715a and the second opening 715b. Alternatively, the third opening may be located on the -Y direction side compared to the first opening and the second opening, and the fourth opening may be located on the +Y direction side compared to the first opening and the second opening.

[0407] Next, the manufacturing method of the planar light source 700 of this embodiment will be described.

[0408] Figure 32A It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0409] Figure 32B It is a schematic cross-sectional view illustrating the manufacturing method of a planar light source.

[0410] First, a wiring substrate 710 is prepared. In the wiring substrate 710 prepared here, a second cover layer 715 covers the area around the first through hole 716a and the second through hole 716b on the lower surface of the insulating layer 716 in such a way that the first through hole 716a and the second through hole 716b are exposed, thereby exposing a portion of the first wiring layer 713 and the second wiring layer 714.

[0411] Next, similar to the first embodiment, the light guide component 130 and the light source 120 are disposed on the wiring substrate 710.

[0412] Next, the first wiring component 751 and the second wiring component 752 are formed. Specifically, as follows: Figure 32A As shown, the first conductive paste 751F is configured to fill the first through-hole 716a, the third through-hole 119a, and the first opening 715a, and is connected to the first wiring layer 713 via the lower surface of the second cover layer 715. Similarly, as... Figure 32B As shown, the second conductive paste 752F is configured to fill the second through-hole 716b, the fourth through-hole 119b, and the second opening 715b, and is connected to the second wiring layer 714 via the lower surface of the second cover layer 715. The first conductive paste 751F and the second conductive paste 752F can be configured simultaneously or separately.

[0413] Each conductive paste 751F and 752F is applied to the wiring substrate 710, for example, by printing with a squeegee or a pressing machine. As described above, the second cover layer 715 is disposed around the first through-hole 716a on the lower surface of the insulating layer 716. Therefore, the first conductive paste 751F can be easily pressed into the first through-hole 716a, the third through-hole 119a, and the first opening 715a using a pressing machine M such as a printing press. The same applies to the second conductive paste 752F. The pressing machine M can be equipped with a roller inside. The roller rotates, causing the conductive paste filled in the pressing machine M to be supplied in a pressed state. Thus, the first conductive paste 751F can be easily pressed into the first through-hole 716a, the third through-hole 119a, and the first opening 715a. The same applies to the second conductive paste 752F.

[0414] The subsequent sequence is the same as the manufacturing method of the planar light source 100 in the first embodiment, so its description is omitted. The cured product of the first conductive paste 751F corresponds to the first wiring component 751. The cured product of the second conductive paste 752F corresponds to the second wiring component 752. However, it is also possible to prepare the first conductive paste, which becomes the first part 751a and the second conductive paste, which becomes the third part 752a during curing, and then prepare the third conductive paste, which becomes the second part 751b and the fourth conductive paste, which becomes the fourth part 752b during curing.

[0415] The first through hole 716a, the third through hole 719a, and the first opening 715a can overlap completely identically or overlap in a staggered manner. Similarly, the second through hole 716b, the fourth through hole 719b, and the second opening 715b can overlap completely identically or overlap in a staggered manner.

[0416] As described above, in the planar light source 700 of this embodiment, the wiring substrate 710 has a second cover layer 715 that covers the area around the first through-hole 716a and the second through-hole 716b on the lower surface of the insulating layer 716, exposing a portion of the first wiring layer 713 and the second wiring layer 714. Furthermore, the second portion 751b of the first wiring member 751 is connected to the first portion 751a and is in contact with the portion of the first wiring layer 713 exposed from the second cover layer 715 via the lower surface of the second cover layer 715. Additionally, the fourth portion 762b of the second wiring member 752 is connected to the third portion 752a and is in contact with the portion of the second wiring layer 714 exposed from the second cover layer 715 via the lower surface of the second cover layer 715.

[0417] Thus, the second cover layer 715 is disposed on the lower surface of the insulating layer 716 around the first through-hole 716a and the second through-hole 716b. If the first opening 715a and the second opening 715b of the second cover layer 715 have the same opening diameter as the first through-hole and the second through-hole, the force for pressing the conductive paste into the conductive paste is increased during printing, making it easier to place the first portion 751a of the first wiring component 751 inside the first through-hole 716a (i.e., the light source side of the first through-hole). Similarly, it is easy to place the third portion 752a of the second wiring component 752 inside the second through-hole 716b (i.e., the light source side of the second through-hole). Therefore, in the electrical connection structure between the wiring layers 713 and 714 in the wiring substrate 710 and the electrodes 124b and 124c in the light source 120, the generation of poor connection can be suppressed.

[0418] Furthermore, the second cover layer 715 is provided with a third opening 715c, which is separated from the first through hole 716a and exposes a portion of the first wiring layer 713, and a fourth opening 715d, which is separated from the second through hole 716b and exposes a portion of the second wiring layer 714. That is, the second cover layer 715 exposes both the first wiring layer 713 and the second wiring layer 714. Therefore, electrical connection between the first wiring layer 713 and the second wiring layer 714 can be suppressed.

[0419] Furthermore, the distance D7 between the third opening 715c and the fourth opening 715d is longer than the distance D6 between the first through hole 716a and the second through hole 716b. Therefore, short circuits in the first wiring layer 713 and the second wiring layer 714 can be suppressed.

[0420] <Eighth Implementation Method>

[0421] Next, the eighth embodiment will be described.

[0422] Figure 33This is a schematic bottom view showing an enlarged portion of the wiring substrate in the planar light source of this embodiment.

[0423] The planar light source 800 of this embodiment differs from the planar light source 700 of the seventh embodiment in the configuration of the first wiring layer 813, the second wiring layer 814, and the second cover layer 815 in the wiring substrate 810.

[0424] Furthermore, in the following description, only the differences from the seventh embodiment will be explained in principle. Except for the matters described below, it is the same as the seventh embodiment.

[0425] The first wiring layer 813 and the second wiring layer 814 are configured to sandwich the first through hole 716a and the second through hole 716b. The shapes of the first wiring layer 813 and the second wiring layer 814 are substantially the same as those of the first wiring layer 113 and the second wiring layer 114 in the first embodiment.

[0426] In the second cover layer 815, the third opening 815a and the fourth opening 815b are configured to sandwich the first opening 715a and the second opening 715b. When viewed from above, the third opening 815a and the fourth opening 815b are semi-circular in shape. However, the shapes of the third and fourth openings are not limited to those described above.

[0427] Thus, the third opening 815a and the fourth opening 815b can also be configured to sandwich the first opening 715a and the second opening 715b. Therefore, even if the through holes 716a and 716b are offset relative to the wiring layers 813 and 814 when forming the wiring components 751 and 752, the generation of poor connection can be suppressed in the electrical connection structure between the wiring layers 813 and 814 in the wiring substrate 810 and the electrodes 124b and 124c in the light source 120.

[0428] <Ninth Implementation Method>

[0429] Next, the ninth embodiment will be described.

[0430] Figure 34 This is a schematic top view illustrating the planar light source of this embodiment.

[0431] The planar light source 1000 of this embodiment includes a wiring substrate 910 and a light-emitting module 920 disposed on the wiring substrate 910.

[0432] In this embodiment, the wiring substrate 910 has a main body 910a that is generally rectangular in shape when viewed from above, and a plurality of protrusions 910b that are connected to the end of the main body 910a in the Y direction and protrude in the Y direction. A light-emitting module 920 is disposed on the main body 910a. However, the shape of the wiring substrate is not limited to the shape described above; it can also be a polygon or a quadrilateral other than a rectangle (e.g., a roughly trapezoidal shape). Furthermore, the number of protrusions 910b provided on the wiring substrate 910 is not as... Figure 34 It is limited to four as shown, but it can be less than four or more than four.

[0433] Figure 35 This is a magnified view of the light-emitting module in this embodiment, showing the light source... Figure 34 A schematic top view of the area enclosed by the dashed line XXXV.

[0434] Figure 36 yes Figure 35 A schematic cross-sectional view of the XXXVI-XXXVI line.

[0435] The light-emitting module 920 is the same as in the sixth embodiment, having multiple light sources 620, a light guide member 630 with multiple recesses 635, a dividing member 633, a light-transmitting member 634, and a light-adjusting member 636. The light-emitting module 920 also includes multiple wiring layers 921 disposed under the dividing member 633 and a cover layer 922 disposed under the multiple wiring layers 921.

[0436] Multiple light sources 620 Figure 35 As shown, they are arranged along the X and Y directions.

[0437] The same material as that used in wiring layers 113 and 114 in the first embodiment can be used in wiring layer 921. Each wiring layer 921 is as follows... Figure 36 As shown, it is electrically connected to one of the multiple light sources 620.

[0438] An insulating resin can be used in the cover layer 922. The cover layer 922 covers at least a portion of each wiring layer 921.

[0439] The wiring patterns of the multiple wiring layers 921 in the light-emitting module 920 are described below.

[0440] Figure 37 This is an amplification of the light-emitting module in this embodiment, which consists of... Figure 34 The area enclosed by XXXV is shown in a schematic top view with perspective of the wiring pattern.

[0441] In addition, Figure 37 In the diagram, for ease of understanding, areas with wiring layer 921 are represented by dots. Additionally, in... Figure 37In order to make the wiring pattern easier to understand, the recess 635 and the light adjustment component 636 provided in the light guide component 630 are omitted.

[0442] Multiple wiring layers 921 are arranged in groups of five to form wiring layer groups 921S. In this embodiment, each wiring layer group 921S connects four light sources 620 in series. These four light sources 620 are configured to form a matrix with two columns in the X direction and two rows in the Y direction. That is, each wiring layer group 921S is equivalent to a current path that connects four light sources 620 in series. However, the number of light sources connected in each wiring layer group is not limited to the number described above.

[0443] Multiple routing layer groups 921S are arranged in both the X and Y directions. Hereinafter, the multiple routing layer groups 921S arranged along the X direction will be referred to as "row MTs". That is, in this embodiment, the multiple row MTs are arranged along the Y direction. Hereinafter, as... Figure 34 As shown, the row MT closest to the protrusion 910b of the wiring substrate 910 among the multiple rows MT is called "first row MT1". In addition, the row MT adjacent to the first row MT1 in the Y direction among the multiple rows MT is called "second row MT2". In addition, the row MT with the wiring furthest from the protrusion 910b of the substrate 910 among the multiple rows MT is called "final row MTn".

[0444] The following describes the wiring pattern of the wiring layer group 921S belonging to the first row MT1.

[0445] The following, such as Figure 37 As shown, the five wiring layers 921 constituting the wiring layer group 921S belonging to the first row MT1 are also referred to as "first wiring layer 921a", "second wiring layer 921b", "third wiring layer 921c", "fourth wiring layer 921d" and "fifth wiring layer 921e". In addition, one of the four light sources 620 connected in series in the wiring layer group 921S is referred to as "first light source 620a", the light source 620 adjacent to the first light source 620a in the X direction is referred to as "second light source 620b", the light source 620 adjacent to the first light source 620a in the Y direction is referred to as "third light source 620c", and the light source 620 adjacent to the second light source 620b in the Y direction and adjacent to the third light source 620c in the X direction is referred to as "fourth light source 620d".

[0446] The first wiring layer 921a has a pad portion P1 exposed at least partly from the opening 922a of the cover layer 922, and a first electrode 621b connected at one end to the pad portion P1 and electrically connected at the other end to the first light source 620 (see reference). Figure 36The extension P2 is the pad portion. The shape of the pad portion P1 is approximately rectangular in this embodiment. However, the shape of the pad portion can also be a polygon other than a quadrilateral, a circle, or an ellipse. The shapes of the pad portions P3, P5, and P7, described later, are also the same. The extension P2 is covered by the cover layer 922.

[0447] One end of the second wiring layer 921b is electrically connected to the second electrode 621c of the first light source 620a (see reference). Figure 36 One end is electrically connected to the first electrode 621b of the second light source 620b.

[0448] One end of the third wiring layer 921c is electrically connected to the second electrode 621c of the second light source 620b, and the other end is electrically connected to the first electrode 621b of the third light source 620c.

[0449] One end of the fourth wiring layer 921d is electrically connected to the second electrode 621c of the third light source 620c, and the other end is electrically connected to the first electrode 621b of the fourth light source 620d.

[0450] The second wiring layer 921b, the third wiring layer 921c, and the fourth wiring layer 921d are covered by the overlay layer 922.

[0451] The fifth wiring layer 921e has a pad portion P3 exposed at least partially through an opening 922b in the cover layer 922, and an extension portion P4 connected at one end to the pad portion P3 and electrically connected at the other end to the second electrode 621c of the fourth light source 620d. The pad portion P3 is adjacent to the pad portion P1 of the first wiring layer 921a in the X direction. The extension portion P4 is covered by the cover layer 922.

[0452] The pad portions P1 and P3 are further away from the protrusion 910b in the Y direction than the four light sources 620a, 620b, 620c, and 620d. Furthermore, when viewed from below, the pad portions P1 and P3 are located between the four light sources 620 connected in series in the wiring layer group 921S belonging to the first row MT1 and the four light sources 620 connected in series in the wiring layer group 921S belonging to the second row MT2. Therefore, the pad portions P1 and P3 of the wiring layer group 921S belonging to the first row MT1 can be separated from the outer edge of the main body portion 121 of the wiring substrate in the Y direction on the side of the protrusion 910b. In this case, the distance between the pad portion P1 and P2 of the wiring layer group 921S belonging to the first row MT1 of this embodiment and the outer edge of the protrusion 910b side of the main body portion 121 of the wiring substrate in the Y direction can be greater than the distance between the pad portion P1 and P2 and the outer edge of the protrusion 910b side of the main body portion 121 of the wiring substrate in the Y direction when the pad portion P1 is located between the light source 620a and the light source 620c and the pad portion P3 is located between the light source 620b and the light source 620d.

[0453] Next, the wiring pattern of wiring layer group 921S belonging to the second row MT2 will be described.

[0454] The routing layer group 921S belonging to the second row MT2 is the same as the routing layer group 921S belonging to the first row MT1, consisting of a first routing layer 921f, a second routing layer 921g, a third routing layer 921h, a fourth routing layer 921i, and a fifth routing layer 921j. Furthermore, the routing layer group 921S belonging to the second row MT2 is also the same as the routing layer group 921S belonging to the first row MT1, with a first light source 620e, a second light source 620f, a third light source 620g, and a fourth light source 620h connected in series. The following only describes the differences between the second row MT2 and the first row MT1.

[0455] When viewed from below, the pad portion P5 of the first wiring layer 921f is located between the first light source 620e and the third light source 620g. Furthermore, when viewed from below, the pad portion P7 of the fifth wiring layer 921j is located between the second light source 620f and the fourth light source 620h. Additionally, when viewed from below, the pad portions P5 of the first wiring layer 921f and P7 of the fifth wiring layer 921j are configured to sandwich the third wiring layer 921h in the X direction.

[0456] Therefore, compared with the case where the wiring pattern of the wiring layer group 921S belonging to the first row MT1 is the same as the wiring pattern of the wiring layer group 921S belonging to the second row MT2, the distance D8 between the pad portion P1 of the wiring layer group 921S belonging to the first row MT1 and the pad portion P5 of the wiring layer group 921S belonging to the second row MT2 can be shortened.

[0457] Furthermore, the extension P6 of the first wiring layer 921f is connected to the pad portion P5 and electrically connected to the first light source 621e, which is further away from the protrusion 910b than the pad portion P5. Additionally, the extension P8 of the fifth wiring layer 921j is connected to the pad portion P7 and electrically connected to the fourth light source 620h, which is closer to the protrusion 910b than the pad portion P7. The Y-direction length of the extension P8 is shorter than the Y-direction length of the extension P4 in the first row MT1.

[0458] However, the routing pattern of the routing layer group 921S belonging to the second row MT2 can also be the same as the routing pattern of the routing layer group 921S belonging to the first row MT1. Furthermore, the routing pattern of the routing layer group 921S belonging to the rows MT from the second row MT2 to the final row MTn can also be the same as the routing pattern of the routing layer group 921S belonging to the first row MT1, or it can be the same as the routing pattern of the routing layer group 921S belonging to the second row MT2.

[0459] In this embodiment, pads P1 and P5 function as anodes, and pads P3 and P7 function as cathodes.

[0460] Next, the connection structure between the wiring substrate 910 and the light-emitting module 920 will be described.

[0461] Figure 38 It is an enlarged view of the data. Figure 34 A schematic bottom view of the portion enclosed by the dashed line XXXVIII.

[0462] Figure 39 This is an enlarged view showing the wiring substrate in this embodiment, which consists of... Figure 38 A schematic bottom view of the portion enclosed by the dashed line XXXIX.

[0463] Figure 40 This is an enlarged view of the wiring substrate and light-emitting module in this embodiment, showing the components... Figure 38 A schematic bottom view of the portion enclosed by the dashed line XXXIX.

[0464] Figure 41 yes Figure 40 A schematic cross-sectional view of the XLI-XLI line.

[0465] The wiring substrate 910 has an insulating layer 911, a plurality of first wiring layers 912 disposed under the insulating layer 911 and electrically connected to pad portions P3 and P7, and a plurality of second wiring layers 917 disposed under the insulating layer 911 and electrically connected to pad portions P1 and P5. Additionally, the wiring substrate 910 as... Figure 34 As shown, it also includes a display 913 for identification disposed on the insulating layer 911. In addition, the wiring substrate 910 may also have a cover layer (not shown) disposed under a plurality of first wiring layers 912 and second wiring layers 917.

[0466] The insulating layer 911 is made of the same material as the insulating layer 116 in the first embodiment. The insulating layer 911 can also be adhered to the light-emitting module 920 using an adhesive sheet or the like. The insulating layer 911 can be composed of a single layer or multiple layers. Figure 40 as well as Figure 41 As shown, through holes 911a are provided directly below each pad portion P1, P3, P5, and P7 in the insulating layer 911. Each through hole 911a penetrates the insulating layer 911 along the Z direction. In this embodiment, the shape of each through hole 911a when viewed from above is circular. However, the shape of each through hole is not limited to the above shape and may also be a polygon such as a quadrilateral or an ellipse. A wiring component 930 is provided in each through hole 911a.

[0467] Each wiring component 930 is electrically connected to the top pad among multiple pads P1, P3, P5, and P7. Additionally, in Figure 38 , Figure 39 ,as well as Figure 40In the diagram, for ease of understanding, areas where wiring components 930 are located are indicated by dots. Each wiring component 930 is formed by curing a conductive paste.

[0468] Each first wiring layer 912 as Figure 38 As shown, one end of each first wiring layer 912 is located on the protrusion 910b of the wiring substrate 910 and extends onto the main body 910a of the wiring substrate 910. That is, one end of each first wiring layer 912 converges on the protrusion 910b. Furthermore, each first wiring layer 912 is as follows... Figure 40 As shown, one or more wiring components 930 connected to pad portions P3 and P7 are connected. Thus, multiple first wiring layers 912 are electrically connected to the cathodes of multiple wiring layer groups 921S of the light-emitting module 920. One end of the multiple first wiring layers 912 gathered on the protrusion 910b is electrically connected to a driving substrate or the like outside the driving planar light source 1000.

[0469] Each second wiring layer 917 extends on the main body portion 910a of the wiring substrate 910. Furthermore, each second wiring layer 917 is connected to one or more wiring components 930 connected to pad portions P1 and P5. Thus, the plurality of second wiring layers 917 are electrically connected to the anodes of the plurality of wiring layer groups 921S of the light-emitting module 920.

[0470] Thus, a plurality of first wiring layers 912 are provided on the wiring substrate 910. Furthermore, the ends of the plurality of first wiring layers 912 converge at the protrusion 910b. At this time, in the area near the protrusion 910b in the main body 910a, a portion of the plurality of first wiring layers 912 is arranged and converged in the Y direction. Moreover, among the plurality of first wiring layers 912, the portion arranged and converged in the Y direction on the main body 910a needs to be located on the side of the protrusion 910b in the Y direction closer to the wiring member 930 electrically connected to the wiring layer group 921S belonging to the first row MT1.

[0471] The wiring component 930 electrically connected to the wiring layer group 921S belonging to the first row MT1 is located directly below the pad portion P3 in the first row MT1. Therefore, the closer the pad portion P3 is to the outer edge of the protrusion 910b side in the Y direction of the light-emitting module 920, the more it is necessary to shift the portion of the multiple first wiring layers 912 that is gathered in the Y direction on the main body 910a towards the protrusion 910b side in the Y direction. In this case, it is necessary to increase the Y direction dimension of the main body 910a so that the multiple first wiring layers 912 can be accommodated inside the outer edge of the main body 910a. In contrast, in this embodiment, the pad portion P3 of the wiring layer group 921S belonging to the first row MT1 is farther away from the protrusion 910b in the Y direction than the multiple light sources 620 connected in series by the wiring layer group 921S. Therefore, it is possible to separate the pad portion P3 from the outer edge of the protrusion 910b side in the Y direction of the light-emitting module 920. Therefore, without increasing the Y-direction dimension of the main body 910a, multiple first wiring layers 912 can be formed inside the outer edge of the wiring substrate 910. Thus, the wiring substrate 910 can be made compact.

[0472] The identification display 913 is, for example, a display used to identify product batches. The identification display 913 may be, for example, a data matrix, a QR code, a barcode, or a character code composed of a combination of text, numbers, or symbols. The identification display 913 may be made of, for example, a metallic material such as copper.

[0473] The display 913 for identification in this embodiment is as follows: Figure 34 The protrusion 910b is arranged as shown on its upper surface. An insulating layer 911 is sandwiched between the plurality of wiring layers 912 and the identification display 913. The identification display 913 protrudes from the insulating layer 911. However, the identification display may also be arranged on the lower surface of the protrusion or on the surface of the main body. Alternatively, the identification display may not be provided on the wiring substrate.

[0474] The identification display 913 can be a metal layer such as copper disposed on the substrate layer 111 in an insulating manner from the wiring layers 113 and 114. In this case, the metal layer can be partially removed by irradiating the metal layer with a laser or etching the metal layer, thereby forming the identification display 913.

[0475] As another example, a display 913 for identification can be formed by partially removing the first cover layer 112 by irradiating it with a laser or etching it, with the first cover layer 112 disposed on the upper surface of the aforementioned metal layer. The removed area in the first cover layer 112 may be continuous or non-continuous. The first cover layer 112 may also be a transparent material; for the purpose of improving visibility, a white material, or a colored material such as green or blue, is preferred. Alternatively, when the metal layer is disposed on the lower surface of the substrate layer, the second cover layer 115 can be partially removed by irradiating it with a laser or etching it on the surface of the metal layer.

[0476] As another example, an identification display 913 can be formed by coating or printing white resin or colored resin, or by pasting stickers.

[0477] Furthermore, the configuration of the wiring substrate 910 is not limited to the above. For example, the thickness of the front end portion of the protrusion 910b in the Y direction may be greater than the thickness of the base end portion (the portion connected to the main body 910a) of the protrusion 910b in the Y direction. Such a front end portion may be formed, for example, by providing a sheet made of a resin material such as polyimide at the front end portion of the protrusion 910b.

[0478] Figure 42 This is a schematic bottom view illustrating another example of the wiring substrate in this embodiment.

[0479] Additionally, for example, such as Figure 42 As shown, an anisotropic conductive film 910d can also be provided on the wiring substrate 910, and multiple first wiring layers 912 are gathered on the anisotropic conductive film 910d. Figure 42 In this configuration, an anisotropic conductive film 910d is provided on the protrusion 910b. Furthermore, terminals 910c for connecting to an external drive substrate can be connected to the protrusion 910b for electrical connection to the anisotropic conductive film 910d. That is, multiple first wiring layers 912 can also be electrically connected to the terminals 910c via the anisotropic conductive film 910d. Alternatively, multiple protrusions may not be provided on the wiring substrate. In this case, multiple anisotropic conductive films can be provided on the lower surface of the main body, and multiple wirings can be aggregated on each anisotropic conductive film. Furthermore, terminals can be electrically connected to each anisotropic conductive film.

[0480] Alternatively, the wiring layer group 921S can be disposed on the upper surface of the wiring substrate 910, such as on the insulating layer 911, instead of on the light-emitting module 920. Furthermore, the wiring layers 912 and 917 only need to be located below the insulating layer 911 at least in the portion that contacts the wiring component 930. Therefore, for example, the wiring layers 912 and 917 can have a first portion disposed below the insulating layer 911 and in contact with the wiring component 930, a second portion disposed above the insulating layer 911, and a third portion penetrating the insulating layer 911 and connecting the first and second portions. Additionally, the wiring layers 912 and 917 can be separated from the through-hole 911a disposed in the insulating layer 911. Moreover, the wiring component 930 can also have a first portion filling the through-hole 911a, and a second portion disposed below the insulating layer 911, connected to the first portion, and in contact with the wiring layers 912 and 917. Furthermore, the wiring layer group 921S can also... Figure 37 The wiring pattern shown is a wiring pattern that is reversed relative to the axis extending along the Y direction.

[0481] Next, the effects of this implementation method will be explained.

[0482] In the planar light source 1000 of this embodiment, in the wiring layer group 921S belonging to the first row MT1, the pad portion P3 is further away from the protrusion 910b in the Y direction than the plurality of light sources 620 connected in series in the wiring layer group 921S. Therefore, without increasing the Y-direction dimension of the main body portion 910a, it is possible to form a plurality of first wiring layers 912 on the inner side of the wiring substrate 910. Thus, the wiring substrate 910 can be made compact.

[0483] Furthermore, in this embodiment, when viewed from below, in the wiring layer group 921S adjacent to the wiring layer group 921S belonging to the second row MT2, the pad portions P5 and P7 are located between the multiple light sources 620 connected in series in the wiring layer group 921S. This shortens the distance between the pad portions P1 and P3 in the first row MT1 and the pad portions P5 and P7 in the second row MT2. As a result, the distance between the through-hole 911a of the insulating layer 911 directly below the pad portions P1 and P3 and the through-hole 911a of the insulating layer 911 directly below the pad portions P5 and P7 can be shortened. When the planar light source 1000 is driven, the temperature of the planar light source 1000 rises and falls depending on whether each light source 620 is lit or not. As a result, the wiring substrate 910, adhesive sheet, light-emitting module 920, and wiring component 930 constituting the planar light source 1000 may deform. At this time, because their coefficients of thermal expansion are different, there is a possibility of stress being applied to the wiring component 930, causing cracks. In this embodiment, as described above, by shortening the distance between the through-hole 911a of the insulating layer 911 located directly below the pad portions P1 and P3 and the through-hole 911a of the insulating layer 911 located directly below the pad portions P5 and P7, the stress acting on the wiring component 930 can be mitigated. As a result, cracks in the wiring component 930 can be suppressed.

[0484] <Variation Example>

[0485] Next, a variation of the ninth embodiment will be described.

[0486] Figure 43 This is a schematic bottom view showing an enlarged portion of the wiring substrate in this variation.

[0487] like Figure 43 As shown, a portion of the outer periphery of the wiring substrate 910 may also have a shape along the outermost first wiring layer 912a of a plurality of first wiring layers 912. For example, in Figure 43 In the main body 910a, the side 910s connected to the protrusion 910b extends along the outer periphery of the light-emitting module 920 and a portion of the first wiring layer 912a in the X direction. Additionally, for example in... Figure 43 In the middle, the side of the protrusion 910b has two steps along the first wiring layer 912a. As a result, the Y-direction dimension of the main body 910a of the wiring substrate 910 can be reduced.

[0488] In the above embodiments, the planar light source is described as having a light guiding component, a dividing component, a light transmitting component, and a light adjusting component. However, the planar light source may also not have a light guiding component, a dividing component, a light transmitting component, and a light adjusting component. That is, the planar light source may also be composed of a wiring substrate and multiple light sources.

[0489] Industrial availability

[0490] This invention can be used, for example, in backlights.

Claims

1. A planar light source, characterized in that, have: A wiring substrate having: an insulating layer having a first through hole and a second through hole spaced apart from each other; a first wiring layer and a second wiring layer disposed below the insulating layer and separated from the first through hole and the second through hole; A light source, disposed on the wiring substrate, has a first electrode and a second electrode that are spaced apart from each other; A first wiring component has a first part and a second part. The first part fills the first through hole and is electrically connected to the first electrode. The second part is disposed under the insulating layer, connected to the first part, and connected to the first wiring layer. as well as The second wiring component has a third portion and a fourth portion. The third portion fills the second through-hole and is electrically connected to the second electrode. The fourth portion is disposed under the insulating layer, connected to the third portion, and connected to the second wiring layer. Viewed from above, the first wiring layer and the second wiring layer are configured to sandwich the first through-hole and the second through-hole. In a top-down view, a portion of the first electrode overlaps with a portion of the first part, and a portion of the second electrode overlaps with a portion of the third part. The area on the side of the first wiring layer that is connected to the second portion and, when viewed from above, opposite the first through-hole, is concave in the direction away from the first through-hole. The area on the side of the second wiring layer that is connected to the fourth part and, when viewed from above, opposite the second through hole, is concave in the direction away from the second through hole.

2. The planar light source according to claim 1, characterized in that, When viewed from above, the distance between the center of the first through hole and the center of the second through hole is longer than the distance between the center of the first electrode and the center of the second electrode.

3. The planar light source according to claim 1, characterized in that, When viewed from above, both the first through hole and the second through hole are circular. The shape of the region connected to the second part and opposite the first through hole when viewed from above, and the shape of the region connected to the fourth part and opposite the second through hole when viewed from above, are both arc-shaped.

4. The planar light source according to claim 1, characterized in that, The light source also has: A first terminal, disposed below the first electrode and connected to the upper end of the first portion, having an area above the area of ​​the first electrode when viewed from above; and The second terminal is disposed below the second electrode and connected to the upper end of the third part, and its area when viewed from above is above the area of ​​the second electrode.

5. The planar light source according to claim 4, characterized in that, The first terminal covers the first through hole when viewed from above. The second terminal covers the second through hole when viewed from above.

6. The planar light source according to claim 1, characterized in that, It also has a cover layer that covers the first wiring component and the second wiring component.

7. The planar light source according to any one of claims 1 to 6, characterized in that, The first wiring component and the second wiring component each have a base material made of resin material and at least one metal particle disposed in the base material.

8. A method for manufacturing a planar light source, characterized in that, have: The process of preparing a wiring substrate includes: an insulating layer having a first through hole and a second through hole that are separated from each other; a first wiring layer and a second wiring layer disposed below the insulating layer and separated from the first through hole and the second through hole; and, in a top view, the first wiring layer and the second wiring layer are configured to sandwich the first through hole and the second through hole. A process of arranging a light source comprising a first electrode and a second electrode spaced apart from each other on the wiring substrate. as well as The process of forming a first wiring component and a second wiring component involves the first wiring component filling the first through-hole, being disposed below the insulating layer, connected to the first wiring layer, and electrically connected to the first electrode of the light source. The second wiring component is separated from the first wiring component, filling the second through-hole, being disposed below the insulating layer, connected to the second wiring layer, and electrically connected to the second electrode of the light source. A first wiring component has a first part and a second part. The first part fills the first through hole and is electrically connected to the first electrode. The second part is disposed under the insulating layer, connected to the first part, and connected to the first wiring layer. as well as The second wiring component has a third portion and a fourth portion. The third portion fills the second through-hole and is electrically connected to the second electrode. The fourth portion is disposed under the insulating layer, connected to the third portion, and connected to the second wiring layer. In a top-down view, a portion of the first electrode overlaps with a portion of the first part, and a portion of the second electrode overlaps with a portion of the third part. The area on the side of the first wiring layer that is connected to the second portion and, when viewed from above, opposite the first through-hole, is concave in the direction away from the first through-hole. The area on the side of the second wiring layer that is connected to the fourth part and, when viewed from above, opposite the second through hole, is concave in the direction away from the second through hole.

9. The method for manufacturing a planar light source according to claim 8, characterized in that, In the process of arranging the light source on the wiring substrate, after arranging the light guide component on the wiring substrate, the light source is arranged in the light source arrangement section provided on the light guide component.

10. The method for manufacturing a planar light source according to claim 8, characterized in that, The process of forming the first wiring component and the second wiring component includes: The steps of configuring a first conductive paste to fill the first through-hole and be in contact with the first wiring layer, and configuring a second conductive paste to fill the second through-hole and be in contact with the second wiring layer; and The process of curing the first conductive paste and the second conductive paste.

11. The method for manufacturing a planar light source according to claim 8, characterized in that, The process of forming the first wiring component and the second wiring component includes: The process of filling the first through hole with a first conductive paste and filling the second through hole with a second conductive paste; The process of curing the first conductive paste and the second conductive paste; The steps of configuring a third conductive paste to bond with the cured product of the first conductive paste and the first wiring layer, and configuring a fourth conductive paste to bond with the cured product of the second conductive paste and the second wiring layer; and The process of curing the third conductive paste and the fourth conductive paste.

12. The method for manufacturing a planar light source according to claim 8, characterized in that, The process of forming the first wiring component and the second wiring component includes: The process of filling the first through hole with a first conductive paste and filling the second through hole with a second conductive paste; The steps of configuring a third conductive paste to be bonded to the first conductive paste and the first wiring layer, and configuring a fourth conductive paste to be bonded to the second conductive paste and the second wiring layer; and The process of curing the first conductive paste, the second conductive paste, the third conductive paste, and the fourth conductive paste.

13. The method for manufacturing a planar light source according to claim 10, characterized in that, In the process of configuring the light source, a light guide component is also configured on the wiring substrate; After the process of configuring the light source and before the process of forming the first wiring component and the second wiring component, there is a process of configuring a light-transmitting resin component in the light source configuration section of the light guide component and in the gap between the light guide component and the light source.

14. The method for manufacturing a planar light source according to any one of claims 10 to 13, characterized in that, The light source also has a first terminal disposed below the first electrode and a second terminal disposed below the second electrode. The light source is configured such that, when viewed from above, the first terminal covers the first through-hole, and the second terminal covers the second through-hole.

Images