JP7640864B2 - Light Emitting Module - Google Patents

Description

This disclosure relates to a light-emitting module.

Light-emitting modules using light-emitting elements such as light-emitting diodes have been proposed (Patent Documents 1 and 2, etc.).

JP 2011-203720 A JP 2013-26240 A

The purpose of this disclosure is to provide a light-emitting module with minimal unevenness in light emission.

The present disclosure includes the following configurations.
(1) A light guide member including an upper surface serving as a light emitting surface, a lower surface opposite to the upper surface, and a hole opening on the lower surface side;
A light source disposed in the hole;
A first light reflective member disposed above the light source;
Equipped with
the lower surface of the light guide member has an inclined surface surrounding the hole and positioned outside the first light reflective member in a top view,
The inclined surface is
a first region disposed between a first upper end located below the upper surface of the light source and a first lower end located below the first upper end on a side closer to the hole than the first upper end;
a second region that is disposed between a second upper end located above the first upper end and a second lower end located below the second upper end on a side closer to the hole than the second upper end and that is disposed outside the first region in a top view,
a cross-sectional shape of the first region includes a curve and/or a straight line that is located above a first virtual line that connects the first upper end and the first lower end at the shortest distance,
A light-emitting module, wherein the cross-sectional shape of the second region includes a curve and/or a straight line that is arranged above a second virtual line that connects the second upper end and the second lower end at the shortest distance.
(2) The light-emitting module of (1), wherein the hole is a bottomed hole having an opening on the lower surface side of the light-guiding member, and the first light-reflective member is disposed on the upper surface of the light-guiding member.
(3) The light-emitting module according to (2), wherein the bottomed hole portion has a side surface and a bottom, and the first upper end is located below the bottom.
(4) The light-emitting module of (3), wherein the height from the lower end of the bottomed hole to the first upper end of the first region is 12.5% or more and 40% or less of the depth of the bottomed hole.
(5) Any of the light-emitting modules (1) to (4), wherein the hole portion is a through-hole portion having openings on the upper surface and the lower surface of the light-guiding member, and the first light-reflective member is positioned above the light source within the through-hole portion.
(6) Any of the light-emitting modules according to (1) to (5), wherein the first region and the second region are adjacent to each other.
(7) Any of the light emitting modules (1) to (6), wherein the light guiding member is rectangular when viewed from above, and the first region is widest between the center of the light guiding member and a corner of the light guiding member.

This disclosure makes it possible to provide a light-emitting module with minimal unevenness in light emission.

FIG. 2 is a schematic top view showing a light-emitting module according to an embodiment. 1B is a schematic plan cross-sectional view taken along line IB-IB in FIG. 1A. FIG. 1B is a schematic cross-sectional plan view showing a modification of FIG. 1A. FIG. 1B is a top view of the light-guiding member in FIG. 1A. FIG. 1B is a bottom view of the light-guiding member in FIG. 1A . FIG. 2C is a schematic end view showing the IIC-IIC' cross section of the light-guiding member of FIG. 2B. 2D is a schematic bottom view for explaining the size and the like of the light guiding member of FIG. 2C. FIG. FIG. 1B is a schematic cross-sectional view showing the light source in FIG. 1A. 4B is a schematic cross-sectional view (cross-section along line IVC-IVC in FIG. 4B) showing a light-emitting module according to another embodiment, and FIG. FIG. 4B is a bottom view of the light-guiding member in FIG. 4A. 4C is a schematic cross-sectional view showing the IVC-IVC' cross section of the light-guiding member of FIG. 4B. 4D is a schematic bottom view for explaining the size and the like of the light guiding member of FIG. 4C. FIG. FIG. 11 is a schematic cross-sectional view showing a light-emitting module according to yet another embodiment. FIG. 4 is a top view showing a plurality of units of light guide members. FIG. 6B is a perspective view of the light-guiding member of FIG. 6A. 1 is a schematic diagram showing a liquid crystal display device to which a light-emitting module of the present invention is applied;

The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions and positions (for example, "upper", "lower" and other terms including these terms) are used as necessary, but the use of these terms is an expression for facilitating understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. In the following description, an XYZ orthogonal coordinate system is adopted. The optical axis of the light-emitting module is parallel to the Z axis. The Z direction is also referred to as the up-down direction or thickness direction. Furthermore, a top view does not necessarily refer only to a state viewed from the top, but may also refer to a state viewed from the bottom. Parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members.
Furthermore, the embodiments shown below are examples for embodying the technical ideas of the present invention, and do not limit the present invention to the following. The dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative, and are not intended to limit the scope of the present invention, unless otherwise specified. The sizes and positional relationships of the members shown in the drawings may be exaggerated to clarify the explanation. In addition, end views showing only the cut surfaces may be used as cross-sectional views.

Embodiment 1 [Light Emitting Module]
As shown in FIG. 1A , the light emitting module 20 according to the first embodiment includes a light guide member 10, a light source 1, and a first light reflective member 8.
The light emitting module 20 may further include a light-transmitting member 6, sealing members 7 and 9, and the like.

One light emitting module can have one light source 1 as shown in FIG. 1A. Alternatively, one light emitting module can have multiple light sources 1 as in the arrangement shown in FIG. 6A and FIG. 6B. When one light emitting module has multiple light sources 1, the multiple light sources 1 are connected so that each is driven independently, or the multiple light sources 1 are connected as one group so that each group is driven independently. This makes it possible to create a light emitting module capable of local dimming.

As shown in Figs. 2A to 2D, the light guide member 10 has an upper surface 101 and a lower surface 102 opposite to the upper surface 101. The light guide member 10 further has a hole 12 that opens to the lower surface 102 side. In the first embodiment, the hole 12 is a bottomed hole (recess) that opens only to the lower surface. The light source 1 is disposed in this hole 12. In this embodiment, the bottomed hole 12 in which the light source 1 is disposed may be referred to as a recess (second recess). A first light reflective member 8 is disposed above the light source 1. In this embodiment, the first light reflective member 8 is disposed on the upper surface 101 of the light guide member 10 located above the light source 1. If the upper surface 101 of the light guide member 10 located above the light source 1 has a recessed portion (sometimes referred to as a first recess 11), the first light reflective member 8 is disposed in this first recess 11.

(Light guiding member)
The light guide member 10 is a translucent plate-like member that receives light from a light source and outputs the light as planar light. The upper surface 101 of the light guide member 10 is an output surface of the light emitting module, and is an upper surface that extends in the XY plane direction perpendicular to the optical axis Z.

(Hole, bottomed hole (second recess))
The hole (second recess) 12 is a portion where the light source 1 is disposed. As shown in FIG. 2C, the second recess 12 is a recessed portion defined by a bottom (second bottom) 12a and a side (second side) 12b. The depth of the second recess 12 (H2 in FIG. 2C) can be, for example, 15% to 50% of the thickness of the light guide member, and preferably 10% to 40%. The depth of the second recess 12 can be 50% to 100% of the thickness of the light source 1.

The second recess 12 is surrounded by the inclined surface 13 in top view. In top view, the second recess 12 and the first light reflective member 8 at least partially overlap. When the light guiding member 10 has the first recess 11, it is preferable that the second recess 12 and the first recess 11 at least partially overlap. In top view, it is preferable that the center of the first light reflective member 8 and the center of the second recess 12 approximately coincide. When the light guiding member 10 has the first recess 11, it is preferable that the center of the first recess 11 and the center of the second recess 12 approximately coincide in top view.

The second recess 12 is a cylindrical or truncated pyramidal recess. For example, the second recess 12 can be a cylindrical, prismatic, conical, or pyramidal recess, or a partially deformed shape of any of these. The shape of the opening of the second recess 12 in a plan view can be, for example, a polygon such as a square, pentagon, or hexagon, a circle, or an ellipse.

As shown in FIG. 2C, the second recess 12 is defined by a bottom (second bottom 12a) including the deepest part of the second recess 12 and a side (second side 12b) surrounding the second bottom 12a in a top view. It is preferable that the center of the opening of the second recess 12 and the center of the second bottom 12a coincide in a top view. It is preferable that the second bottom 12a is a surface that is approximately perpendicular to the optical axis of the light-emitting module. The second side 12b of the second recess 12 can be a straight line or a curve that is convex or concave toward the center of the second recess 12 in a cross section passing through the center of the second recess 12, or a combination of these. The depth of the second recess 12 (H2 in FIG. 2C) can be, for example, 15% to 50% of the thickness of the light-guiding member (T in FIG. 2C), and preferably 10% to 40%.

(Inclined surface)
As shown in Fig. 2C, the lower surface 102 of the light guide member 10 has an inclined surface 13 surrounding the second recess 12 in a top view. The inclined surface 13 has a lower end (e.g., a first lower end of the first region) 130U on the side close to the second recess 12, and is inclined to have a second upper end 132U outside the lower end 130U. The inclined surface 13 is disposed at a position not overlapping with the first light reflective member 8 in a top view. In other words, the innermost edge U2 of the inclined surface 13, i.e., the lower end 130U of the inclined surface 13, is disposed outside the outer edge U1 of the first light reflective member 8 in a top view.

On the lower surface 102, the lower end 12U of the second side surface 12b of the second recess 12 and the inclined surface 13 may be continuous or separated. In the example shown in FIG. 2C, the lower end 12U of the second side surface 12b and the inclined surface 13 are separated. That is, on the lower surface 102 side, a second portion 133, which is a surface that is approximately perpendicular to the optical axis, is disposed between the second recess 12 and the inclined surface 13. The distance of such a second portion 133 (D9 in FIG. 2D) is, for example, 5% to 15% of the length of one side of the light-guiding member 10. It is preferable that such a second portion 133 is a smooth surface.

The inclined surface 13 has a first region 131 and a second region 132. In a top view, the first region 131 is located outside the light source 1, and the second region 132 is located outside of the first region 131. The first region 131 is a region located between a first upper end and a first lower end. The first upper end is located lower than the upper surface of the light source in the vertical direction of the light guide member. The first lower end is located lower than the first upper end. The second region 132 is a region located between a second upper end and a second lower end. The second upper end is located higher than the first upper end in the vertical direction of the light guide member. The second lower end is located lower than the second upper end.

The cross-sectional shape of the first region includes curves and/or straight lines that are located above a first virtual line that connects the first upper end and the first lower end at the shortest distance. The cross-sectional shape of the two regions includes curves and/or straight lines that are located above a second virtual line that connects the second upper end and the second lower end at the shortest distance. In other words, the first region 131 is configured with a concave curve that is concave toward the upper surface 101 in cross-sectional view, and the second region 132 is configured with a convex curve or straight line that is convex toward the lower surface 102 in cross-sectional view.

The first region 131 and the second region 132 can be adjacent to each other, as shown in FIG. 2C. In other words, the upper end (first upper end) of the first region 131 and the lower end (second lower end) of the second region can be aligned (131U in FIG. 2C).

The first region 131 and the second region 132 are preferably smooth surfaces. Alternatively, the first region 131 and the second region 132 can be rough surfaces. In this case, the surface roughness of the first region 131 and the surface roughness of the second region 132 can be approximately the same. Alternatively, the surface roughness of the first region 131 can be greater or less than the surface roughness of the second region 132.

The first region 131 has a first upper end 131U below the upper surface 1a of the light source 1 in the vertical direction. As shown in FIG. 1A, when the upper surface 1a of the light source 1 is in direct contact with the second bottom 12a of the second recess 12, the first upper end 131U of the first region 131 is located between the lower end 12U of the second side surface 12b of the second recess 12 and the upper surface 1a of the light source 1 in the vertical direction. In addition, when the upper surface 1a of the light source 1 and the second bottom 12a of the second recess 12 are joined via a translucent member 6, the upper end (first upper end 131U) of the first region 131 may be located below the bottom 12a of the hole portion 12 (the second bottom 12a of the second recess 12) in the vertical direction. In other words, it is preferable that the upper end of the first region 131 is located between the lower end and the upper end of the translucent resin member 3 of the light source 1. In this way, by adjusting the ratio of the first region 131 to the side surface of the light source 1, it is possible to distribute the light and suppress uneven light emission.

The first upper end 131U is disposed at the uppermost position in the first region 131. The first upper end 131U is located at the outermost position in the first region 131. This arrangement allows the light emitted from the light emitting device to be efficiently guided to the upper surface, which is the light emitting surface.

The height of the first upper end 131U of the first region 131 can be adjusted according to the thickness of the translucent resin member 3. For example, it is preferable that the height of the first region 131 from the lower end of the second recess 12 (corresponding to 130U in FIG. 2C) to the first upper end 131U in the vertical direction (height T1 in FIG. 2C) is smaller than the depth H2 of the second recess 12. Alternatively, if the thickness of the translucent resin member 3 placed in the second recess 12 is different from the depth H2 of the second recess 12, it is preferable to make the height T1 smaller than the thickness of the translucent resin member 3. For example, this height T1 can be 12.5% to 40% of the thickness of the translucent resin member 3, and preferably 25% to 70%.

The first region 131 may have a rise angle (α1 in FIG. 2C) of 90 degrees or more and 160 degrees or less at the edge closest to the second recess 12. By setting the rise angle on the second recess side in this way, the light emitted from the light source can be dispersed at the corners in the light-guiding member 10. Here, the rise angle refers to the angle between the tangent to the lower end of the inclined surface (the first lower end of the first region) and the plane perpendicular to the optical axis. On the side of the first region 131 farther from the second recess 12, the rise angle may be, for example, 1 degree or more and 20 degrees or less from the plane perpendicular to the optical axis, and 1 degree or more and 8 degrees or less is preferable.

2B, the first region 131 has a different width from the center of the second recess 12 to the upper end of the first region 131 (the width of the first region 131) when viewed from above. For example, when the light-guiding member has a rectangular shape when viewed from above, it is preferable that the first region 131 is widest between the center of the light-guiding member 10 and a corner of the light-guiding member 10 and is narrowest between the center of the light-guiding member 10 and the center of a side of the light-guiding member 10 when viewed from above. This makes it possible to increase the proportion of light that is guided in the corner direction of the light-guiding member 10.

2D, in a top view, the distance D1 between the first upper end 131U and the second upper end 132U located on a straight line L1 passing through the center of the light-guiding member 10 and the center of the side of the light-guiding member 10 can be 10% to 30% of the length H0 of one side of the light-guiding member 10. The distance D2 from the first upper end 131U closest to the corner of the light-guiding member 10 to the closest side of the light-guiding member 10 can be 5% to 15% of the length H0 of one side of the light-guiding member 10. In addition, in a top view, the distance D3 between the first upper end 131U and the second upper end 132U located on a straight line L2 passing through the center of the light-guiding member 10 and the corner of the light-guiding member 10 can be 7% to 17% of the length H0 of one side of the light-guiding member 10. The distance D4 between the first upper end 131U located on the straight line L1 and the lower end 130U of the inclined surface 13 (the first lower end of the first region) can be 5% to 18% of the length H0 of one side of the light guide member 10. The distance D5 between the first upper end 131U located on the straight line L2 and the lower end 130U of the inclined surface 13 (the first lower end of the first region) can be 25% to 45% of the length H0 of one side of the light guide member 10. In addition, as shown in FIG. 1B, the first upper end 131U of the first region 131 may change in a curved manner when viewed from above, or the light guide member 10A may change linearly as shown in FIG. 1C. With such a shape, the light emitted from the light source can be efficiently guided to the upper surface, which is the light emitting surface.

The second region 132 has a second upper end 132U above the first upper end 131U in the vertical direction. The second region 132 has a second upper end 132U above the upper surface 1a of the light source 1 in the vertical direction. The second upper end 132U is located at the uppermost position in the second region 132 in the vertical direction. The second upper end 132U is located at the outermost position of the second region 132 in a top view. It is preferable that the entire second region 132 is located above the first region 131. In other words, it is preferable that the lower end (second lower end) of the second region 132 is located at the lowermost position in the second region 132 in the vertical direction. In this way, by making the second region 132 a surface that is concave with respect to the upper surface, the light emitted from the light emitting device can be efficiently guided to the upper surface, which is the light emitting surface, while being condensed.

It is preferable that the height of the second region 132 from the second portion 133 to the second upper end 132U (height T2 in FIG. 2C) is greater than the depth H2 of the second recess 12. For example, this height T2 can be 112.5% or more and 140% or less of the depth H2 of the second recess.

The rise angle (α2 in FIG. 2C) of the slope at the edge of the second region 132 closest to the second recess 12 can be 130 degrees or more and 170 degrees or less, and preferably 135 degrees or more and 165 degrees or less. By setting the rise angle on the second recess side in this manner, the light emitted from the light source can be efficiently dispersed within the light-guiding member 10. The rise angle α1 of the first region 131 and the rise angle α2 of the second region 132 may be approximately the same, or α1 < α2.

(First recess)
1A, 2A, and 2C, the upper surface 101 of the light-guiding member 10 may include a first recess 11. The first recess 11 has a function of, for example, spreading light within the surface of the light-guiding member 10. Note that the first recess 11 is not essential, and the upper surface 101 of the light-guiding member 10 may be a flat surface.

The first recess 11 is a depression having a substantially pyramidal or truncated pyramidal shape. For example, the first recess 11 can be a cone, pyramid, truncated cone, truncated pyramid, or a shape that is a partial modification of these. The shape of the opening of the first recess 11 when viewed from above may be, for example, a polygon such as a rectangle, pentagon, or hexagon, or may be a circle or ellipse as shown in FIG. 2A. It is preferable that the size of the opening of the first recess 11 is at least larger than the size of the light source 1 when viewed from above.

The first recess 11 is located at the center of the first recess 11 in top view. As shown in FIG. 2C, the first recess 11 is defined by a bottom (first bottom) 11a including the deepest part of the first recess 11 and a side (first side) 11b surrounding the first bottom 11a in top view. The first bottom 11a of the first recess 11 is preferably a surface substantially perpendicular to the optical axis of the light source. The side 11b defining the first recess 11 can be a straight line or a curved line that is convex or concave toward the center of the first recess 11 in a cross section passing through the center of the first recess 11, or a combination of these. The depth of the first recess 11 (H1 in FIG. 2C) can be, for example, 10% to 45% of the thickness of the light-guiding member 10 (T in FIG. 2C), and preferably 10% to 38%.

The upper surface 101 may have a first portion 14 including a surface perpendicular to the optical axis around the first recess 11. The first portion 14 may be a flat surface or a surface with minute recesses or protrusions. The first portion 14 is located at a position furthest from the lower surface in the optical axis direction. The first portion 14 may be omitted. In other words, the entire upper surface 101 may be the first recess 11.

Examples of the material of the light-guiding member 10 include resin materials such as thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, and polyester, thermosetting resins such as epoxy and silicone, and glass. The thickness of the light-guiding member 10 (T in FIG. 2C) can be, for example, 0.1 mm or more and 5 mm or less, and preferably 0.5 mm or more and 3 mm or less. The size of the light-guiding member 10 can be, for example, 1 cm or more and 200 cm or less on one side of the upper surface 101 or the lower surface 102, and preferably 3 cm or more and 30 cm or less. The shape of the light-guiding member 10 in a planar view can be, for example, a rectangle, a circle, etc., and a rectangle is preferable.

The light guide member 10 is preferably a single layer. It may also have a laminated structure in which multiple light-transmitting layers are stacked. In the case of a laminated structure, the structure may be one in which layers of the same material or layers of different materials are bonded together with an adhesive sheet or the like. In addition, a layer with a different refractive index, such as an air layer, may be provided between any of the layers. This makes it easier to diffuse light, resulting in a light-emitting module with reduced unevenness in brightness.

The light-guiding member 10 can be prepared by molding, for example, injection molding, transfer molding, compression molding, thermal transfer, etc. The light-guiding member 10 can also be purchased and prepared.

(First light reflective member 8)
The first light reflective member 8 is disposed above the light source 1. In this embodiment, the first light reflective member 8 is disposed, for example, inside the first recess 11. The first light reflective member 8 is preferably disposed in a region of the first recess 11 that overlaps with at least the light source 1 in a top view. This makes it possible to reflect light, particularly light emitted directly upward from the light source, in the lateral direction, and to prevent the area directly above the light source from becoming too bright compared to other areas.

When the light-guiding member has a first recess 11, the first light-reflective member 8 is preferably disposed in the first recess 11 at a position spaced apart from the upper end of the first side surface that defines the first recess 11. In other words, it is preferable that a portion of the first side surface 11b of the first recess 11 is exposed from the first light-reflective member 8. When viewed from above, the first light-reflective member 8 is disposed outside the inclined surface 13 of the lower surface 102, which will be described later.

In addition, when viewed from above, it is preferable that the size of the first light-reflective member 8 is larger than that of the second recess 12. In other words, when viewed from above, it is preferable that the outer edge of the first light-reflective member 8 is positioned outside the outer edge of the second recess 12.

When the light-guiding member has a second portion 133 around the second recess 12, it is preferable that the second portion 133 and the first light-reflective member 8 overlap when viewed from above.

Examples of the first light reflective member 8 include light reflective materials such as light reflective metals, resin materials containing light diffusing agents, and resin materials containing air bubbles. A white resin member containing a light diffusing agent can be used as a light-transmitting resin material. Examples of light diffusing agents include TiO ₂ , SiO ₂ , Al ₂ O ₃ , ZrO ₂ , and ZnO. Examples of the resin material contained in the sealing member 7 include thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, and polyester, or thermosetting resins such as epoxy and silicone. In particular, the first light reflective member 8 is preferably a silicone resin containing TiO ₂ or polyethylene terephthalate containing air bubbles.

(light source)
The light source 1 includes a light-emitting element 2. The light source 1 may be only the light-emitting element 2, or may be a light-emitting device including the light-emitting element 2 and a resin material or the like as shown in Figs.

The light-emitting element 2 may be a semiconductor light-emitting element having, for example, a light-transmitting substrate such as sapphire and a semiconductor structure laminated on the light-transmitting substrate. The semiconductor structure includes an n-side semiconductor layer, a p-side semiconductor layer, and an active layer sandwiched between the n-side semiconductor layer and the p-side semiconductor layer. The active layer may have a single quantum well (SQW) structure or a multiple quantum well (MQW) structure including a plurality of well layers. The semiconductor structure includes a plurality of semiconductor layers made of nitride semiconductors. The nitride semiconductor includes all compositions in which the composition ratios x and y are changed within the respective ranges in the chemical formula of In _x Al _y Ga _1-x-y N (0≦x, 0≦y, x+y≦1). The emission peak wavelength of the active layer can be appropriately selected according to the purpose. The active layer is configured to be able to emit, for example, visible light or ultraviolet light.

The semiconductor structure may include a plurality of light emitting sections including an n-side semiconductor layer, an active layer, and a p-side semiconductor layer. When the semiconductor structure includes a plurality of light emitting sections, each light emitting section may include well layers having different emission peak wavelengths, or may include well layers having the same emission peak wavelength. The same emission peak wavelength includes a case where the emission peak wavelengths vary by about several nm. The combination of emission peak wavelengths of the plurality of light emitting sections can be appropriately selected. For example, when the semiconductor structure includes two light emitting sections, the combination of light emitted by each light emitting section may be blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and red light, or green light and red light. For example, when the semiconductor structure includes three light emitting sections, the combination of light emitted by each light emitting section may be blue light, green light, and red light. Each light emitting section may include one or more well layers having emission peak wavelengths different from other well layers.

The light-emitting element is preferably a rectangular element with vertical and horizontal dimensions of 1 mm or less when viewed from above, and preferably an element with a size of 500 μm or less, and more preferably 200 μm or less. This makes it possible to realize high-definition images, for example, when performing local dimming on a liquid crystal display device.

As the light source 1, as shown in FIG. 3, a light emitting device having a translucent resin member 3 that covers the light emitting surface of the light emitting element 2 can be used. The translucent resin member 3 may cover the light emitting surface and side surfaces of the light emitting element 2. The translucent resin member 3 may be a translucent material such as an epoxy resin, a silicone resin, or a mixture of these. As the base material of the translucent resin member 3, a material having a higher refractive index than the material of the light guiding member 10 is preferable.

The light-transmitting resin member 3 may contain, in addition to the above-mentioned light-transmitting material, a phosphor that converts the wavelength of the light from the light-emitting element 2 . Examples of the phosphor include yttrium aluminum garnet phosphors (e.g., _Y3 (Al,Ga) _5O12 :Ce), lutetium aluminum garnet phosphors (e.g., _Lu3 (Al,Ga) _5O12 :Ce), _terbium aluminum garnet phosphors (e.g., _Tb3 (Al,Ga) _5O12 :Ce), β-sialon phosphors (e.g., (Si,Al) ₃ (O,N) ₄ :Eu), α-sialon phosphors (e.g., Ca( _Si ,Al) ₁₂ (O,N) _{16 :} Eu), CASN phosphors (e.g., CaAlSiN3:Eu), and SCASN phosphors (e.g., (Sr,Ca) _AlSiN3 :Eu) _. Examples of the phosphor that can be used include nitride phosphors such as _KSF phosphors (e.g., _K2SiF6 :Mn), KSAF phosphors (e.g., _K2 (Si,Al) _F6 :Mn) and fluoride phosphors such as MGF phosphors (e.g., _{3.5MgO.0.5MgF2.GeO2} :Mn), phosphors having a perovskite structure (e.g., CsPb(F,Cl, _Br ,I) ₃ ), and quantum dot phosphors (e.g., CdSe, InP, _AgInS2 , or _AgInSe2 ).

The light-transmitting resin member 3 may have a single layer or a laminated structure in which multiple layers are laminated. The light-transmitting resin member 3 may contain a light diffusing material. Examples of _light diffusing materials include _TiO2 , _SiO2 , _Al2O3 , _ZrO2 , and ZnO.

The translucent resin member 3 preferably has an area larger than the light-emitting surface (top surface) of the light-emitting element 2. In other words, the outer edge of the translucent resin member 3 is preferably sized to be placed outside the outer edge of the light-emitting surface of the light-emitting element 2. The translucent resin member 3 may be joined to the light-emitting surface of the light-emitting element 2 by a translucent joining member 4. The translucent joining member 4 is preferably made of a material that transmits 60% or more of the light emitted from the light-emitting element 2, and preferably transmits 90% or more. Examples of materials for the translucent joining member 4 include translucent thermosetting resin materials such as epoxy resin and silicone resin.

As the light source 1, for example, as shown in Fig. 3, a light emitting device having a structure including a light reflective covering member 5 covering the side surface and electrode surface of the light emitting element 2 can be used. Examples of the covering member 5 include a resin material containing _TiO2 , _SiO2 , _Al2O3 , _ZrO2 , ZnO, etc. When the light transmissive resin member covers the side surface of the light emitting element, the covering member 5 can cover the lower surface of _the light transmissive resin member and the lower surface of the light emitting element (surface other than the electrode).

The second recess 12 of the light-guiding member 10 is provided with a translucent member 6 that joins the light-guiding member 10 and the light source 1. In this case, the translucent member 6 may be disposed only in the second recess 12, or may be disposed so as to extend from the second recess 12 to the second portion 133 of the light-guiding member 10. The translucent member 6 may be the same as the translucent joining member 4 described above.

(Sealing member)
The sealing members 7 and 9 are light-reflective members disposed opposite the lower surface 102 of the light-guiding member 10. The sealing members 7 and 9 are disposed so as to be in contact with the lower surface 102 of the light-guiding member 10, or so as to be in indirect contact with the lower surface 102 of the light-guiding member 10 via a bonding member or the like. The sealing member 7 is disposed so as to be in contact with the light source 1, or is disposed via a bonding member or the like. The sealing member 7 is preferably light-reflective. The light-reflective sealing member 7 has a reflectance of 60% or more, preferably 90% or more, for the light emitted from the light source 1. As the material of the light-reflective sealing member 7, a resin member containing a large number of bubbles in a translucent resin material can be used. Alternatively, as the sealing member 7, a white resin member containing a light diffusing agent in a translucent resin material can be used. As the light diffusing agent, for example, TiO ₂ , SiO ₂ , Al ₂ O ₃ , ZrO ₂ , ZnO, etc. can be used. Examples of the resin material contained in the sealing member 7 include thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, and polyester, and thermosetting resins such as epoxy and silicone. In particular, silicone resin containing _TiO2 or polyethylene terephthalate containing bubbles is preferable.

The sealing member 7 is preferably disposed around the light source 1 and covers part or all of the lower surface 102, the first side B1, the second side B2, the third side B3, the fourth side B4, and the fifth side B5 of the light-guiding member 10. By disposing the sealing member 7, the light emitted from the light-emitting device can be efficiently guided to the upper surface of the light-guiding member 10 with good brightness. In addition, the light source 1 and the light-guiding member 10 can be reinforced. The sealing member 7 and the light-guiding member 10 may be covered with an air layer in between, or may be covered by direct contact.

[Modification of the Light Emitting Module]
4A , the light-emitting module 41 includes a light-guiding member 40 and a light source 1. The light-emitting module 41 has substantially the same configuration as the light-emitting module 20 described above, except that the shape of the light-guiding member is partially different.

(Light guiding member)
4C , the light-guiding member 40 has an upper surface 401 that serves as a light-emitting surface, and a lower surface 402 opposite to the upper surface 401. A first recess 11 is disposed on the upper surface 401, and a second recess 12 is disposed on the lower surface 402. The lower surface 402 further has inclined surfaces 43 at positions sandwiching the second recess 12 in a cross-sectional view. The light-guiding member 40 has substantially the same configuration as the light-guiding member 40 described above, except that the shape of the inclined surfaces 43 is different.

In this embodiment, as shown in FIG. 4B etc., the inclined surface 43 has a first region 431, a second region 432, and a third region 433 disposed between the first region 431 and the second region 432.

The first region 431 of the light guide member has a shape including a curve and/or a straight line arranged above the first virtual line connecting the first upper end and the first lower end at the shortest distance in a cross-sectional view. In other words, the first region 431 is configured with a concave curve that is concave toward the upper surface 401 side. The third region 433 has a shape including a curve and/or a straight line arranged above the virtual line connecting its upper end (i.e., the lower end of the second region) and its lower end (i.e., the upper end of the first region) at the shortest distance in a cross-sectional view. In other words, it is configured with a concave curve that is concave toward the upper surface 401 side. The second region 432 has a shape including a curve and/or a straight line arranged above the second virtual line connecting the second upper end and the second lower end at the shortest distance in a cross-sectional view. In other words, the second region 432 is configured with a convex curve or a straight line that is convex toward the upper surface 401 side.

The first region 431 has a first upper end 431U between the lower end of the second side surface 12b of the second recess 12 and the second bottom 12a in the vertical direction. The first upper end 431U is located at the uppermost position in the first region 431. The third region 433 is located at a position higher than the first region 431 in the vertical direction. The third region 433 has a third upper end 433U between the lower end of the second side surface 12b of the second recess 12 and the second bottom 12a in the vertical direction. The third upper end 433U is located at the uppermost position in the third region 433. The second region 432 has a second upper end 432U above the third upper end 433U. The second upper end 432U is located at the uppermost position in the second region 432. Furthermore, the second region 432 is disposed above the third upper end 433U of the third region 433 in the up-down direction. The first upper end 431U is preferably located at the outermost position of the first region 431. The third upper end 433U is preferably located at the outermost position of the third region 433. The second upper end 432U is preferably located at the outermost position of the second region 432.

The third region 433 is preferably located entirely above the first region 431. The second region 432 is preferably located entirely above the first region 431 and the third region 433. With this arrangement, the light emitted from the light emitting device can be efficiently guided to the upper surface, which is the light emitting surface.

It is preferable that the height of the first region 431 to the first upper end 431U located at the uppermost side (height T11 in FIG. 4C) is smaller than the depth H12 of the second recess 12. For example, this height T11 can be 12.5% or more and 40% or less of the depth H12 of the second recess 12.

The rising angle of the inclination at the edge of the first region 431 closest to the second recess 12 (α11 in FIG. 4A) can be 90 degrees or more and 160 degrees or less. By setting the first region 431 to such a rising angle on the second recess side, the light emitted from the light source can be effectively dispersed within the light guide member. Note that on the side of the first region 431 farther from the second recess 12, the rising angle can be, for example, 0.1 degrees or more and 20 degrees or less from the plane perpendicular to the optical axis, and preferably 1 degree or more and 8 degrees or less.

As shown in FIG. 4B, the first region 431 is arranged such that the width from the center of the second recess 12 to the upper end of the first region 431 is equal in all directions in a 360-degree view when viewed from above. This arrangement allows the light emitted from the light source to be efficiently guided to the upper surface, which is the light-emitting surface.

The third region 433 has a height (height T13 in FIG. 4C ) up to the third upper end 433U located on the uppermost side, which is 17.5% to 110% of the depth H12 of the second recess 12, for example.
The rising angle (α13 in FIG. 4A) of the inclination at the edge of the third region 433 closest to the second recess 12 can be 90 degrees or more and 160 degrees or less. By setting the third region 433 to such a rising angle on the second recess side, the light emitted from the light source can be effectively dispersed within the light guide member. Note that, on the side of the third region 433 farther from the second recess 12, the rising angle can be, for example, 1 degree or more and 60 degrees or less from the plane perpendicular to the optical axis, and preferably 1 degree or more and 40 degrees or less.

As shown in FIG. 4B, the third region 433 has a different width from the center of the second recess 12 to the upper end of the first region 431 in top view. For example, when the top view shape of the light guide member is a rectangle, it is preferable that the width is widest between the center and the corner of the light guide member in top view and narrowest between the center of the light guide member 10 and the center of the side of the light guide member in top view. For example, as shown in FIG. 4D, the distance between the first upper end 431U of the light guide member 40 and the edge U2 (the first lower end of the first region) which is the lower end of the inclined surface 43 in top view can be 5% to 15% of the length H0 of one side of the light guide member 10. The distance between the first upper end 431U and the third upper end 433U can be 10% to 30% of the length H0 of one side of the light guide member 10. The distance between the third upper end 433U and the second upper end 432U located on the straight line L2 passing through the center of the light guide member 40 and the corner of the light guide member 40 can be 15% to 45% of the length H0 of one side of the light guide member 10. As shown in FIG. 4B, the third upper end 433U of the third region 433 may change in a curved manner when viewed from above, or may change linearly (see the light guide member 10A in FIG. 1C). With such a shape, the light emitted from the light source can be efficiently guided to the upper surface, which is the light-emitting surface.

The height of the second region 432 to the uppermost second upper end 432U (height T12 in FIG. 4C) is 50% or more and 350% or less of the depth H12 of the second recess 12.

The second region 432 may have, for example, an angle (α12 in FIG. 4A) with the lower surface of 100 degrees or more and 150 degrees or less. The height (T12 in FIG. 4C) from the second portion 434 to the second upper end 432U is preferably greater than the depth H12 of the second recess 12. For example, this height T12 may be 80% or more and 500% or less of the depth of the second recess, and preferably 120% or more and 400% or less.

Second embodiment [Light emitting module 50]
The light emitting module 50 according to the second embodiment differs from the first embodiment in that the hole disposed in the light guiding member 54 is a through hole 51, as shown in FIG. 5. The through hole 51 penetrates the light guiding member 54 from the upper surface 54a to the lower surface 54b. That is, the through hole 51 opens to both the upper surface 54a and the lower surface 54b. In the second embodiment, the light source 1 is disposed in the through hole 51. In addition, a translucent first member 52 is disposed in the through hole 51. In this embodiment, the thickness of the light guiding member 54 can be, for example, 50% to 200% of the thickness of the light source, and is preferably 80% to 100%.

The first member 52 contacts the inner wall surface 51a of the light-guiding member 54 that defines the through-hole portion 51 within the through-hole portion 51.

The first light reflective member 53 is disposed above the light source 1. The first light reflective member 53 can be disposed in contact with the upper surface of the light source 1. Alternatively, when the first member 52 is disposed on the upper surface of the light source 1, the first light reflective member 53 is disposed on the first member 52. The first light reflective member 53 may be disposed so as to extend from above the first member 52 to the upper surface 54a of the light guide member 54.

The light-emitting module 50 is the same as in the first embodiment, except that the hole in which the light source 1 is disposed is a through-hole 51. In FIG. 5, the through-hole has a constant width in a cross section parallel to the vertical direction, but this width may vary.

(First member 52)
The first member 52 disposed in the through-hole portion 51 contacts the side surface of the light source 1. The first member 52 may be disposed on the upper surface of the light source 1 in the through-hole portion 51. The first member 52 may be disposed between the light source 1 and the wiring board 35. The first member 52 contacts the entire surface or a part of the inner wall surface 51a of the light guide member 54 that defines the through-hole portion 51. The upper surface of the first member 52 may be flush with the upper surface 54a of the light guide member 54. Alternatively, the upper surface of the first member 52 may be located lower than the upper surface of the light guide member 54.
The material of the first member 52 can be, for example, the same material as that of the light-transmitting member 6 in the first embodiment.

The light-emitting modules 20, 41, and 50 according to each of the embodiments described above can be manufactured by a known method, such as the manufacturing method described in JP 2019-12681 A or a manufacturing method equivalent thereto.

The light-emitting modules 20, 41, and 50 can be used as backlights for a liquid crystal display device 30, for example, as shown in FIG. 7. In this case, a diffusion sheet 31, a lens sheet 32, a lens sheet 33, a liquid crystal panel 34, etc. can be laminated on the light-emitting surface side of the light-emitting module having a light source 1 and a light-guiding member 10, 40, and 54.

REFERENCE SIGNS LIST 1 light source 1a upper surface 2 light emitting element 3 light-transmitting resin member 4 light-transmitting joining member 5 covering member 6 light-transmitting member 7, 9 sealing member 8, 53 first light reflective member 10, 10A, 40, 54 light guide member 101, 401, 54a upper surface 102, 402, 54b lower surface 11 first recess 11a first bottom 11b first side surface 12 second recess (hole)
12a Bottom (second bottom)
12b Side (second side)
12U lower end 13, 43 inclined surface 130U lower end 131, 431 first region 131U, 431U first upper end 132, 432 second region 132U, 432U second upper end 133, 434 second portion 433 third region 433U third upper end 14 first portion 20, 41, 50 light emitting module 30 liquid crystal display device 31 diffusion sheet 32 lens sheet 33 lens sheet 34 liquid crystal panel 35 wiring board 51 through hole portion 51a inner wall surface 52 first member

Claims (6)

a light guide member including an upper surface serving as a light emitting surface, a lower surface opposite to the upper surface, and a hole opening on the lower surface side;
A light source disposed in the hole;
a first light reflective member disposed above the light source;
the lower surface of the light guide member has an inclined surface surrounding the hole and positioned outside the first light reflective member in a top view,
The inclined surface is
a first region disposed between a first upper end located below an upper surface of the light source and a first lower end located below the first upper end on a side closer to the hole than the first upper end;
a second region that is disposed between a second upper end located above the first upper end and a second lower end located below the second upper end on a side closer to the hole than the second upper end and that is disposed outside the first region in a top view,
a cross-sectional shape of the first region includes a curve and/or a straight line that is located above a first virtual line that connects the first upper end and the first lower end at a shortest distance,
a cross-sectional shape of the second region includes a curve and/or a straight line that is located above a second virtual line that connects the second upper end and the second lower end at a shortest distance ,
The first region and the second region are adjacent to each other . The light-emitting module according to claim 1, wherein the hole is a bottomed hole having an opening on the lower surface side of the light-guiding member, and the first light-reflective member is disposed on the upper surface of the light-guiding member. The light-emitting module according to claim 2, wherein the bottomed hole portion has a side surface and a bottom, and the first upper end is located below the bottom. The light-emitting module according to claim 3, wherein the height from the bottom end of the bottomed hole to the first top end of the first region is 12.5% to 40% of the depth of the bottomed hole. The light-emitting module according to claim 1, wherein the hole is a through-hole having openings on the upper surface and the lower surface of the light-guiding member, and the first light-reflective member is disposed above the light source within the through-hole. The light-emitting module according to claim 1, wherein the light-guiding member is rectangular in top view, and the first region is widest between the center of the light-guiding member and a corner of the light-guiding member.