JP7108205B2 - light emitting device - Google Patents

Description

The present disclosure relates to light emitting devices.

A light-emitting device is known in which a plurality of light sources such as LED chips are arranged two-dimensionally on a substrate (for example, Patent Documents 1 to 3 below). As described in Patent Document 3, such a light-emitting device is used as a direct type surface light source, for example, as a backlight for a liquid crystal display device.

In Patent Documents 1 to 3 below, LED elements sealed with glass or resin in which a phosphor is dispersed are connected to a substrate including a circuit pattern, and a plurality of holes are provided in a light guide plate, and each LED A light guide plate is arranged on the substrate so that the elements are positioned inside these holes. In Patent Document 1, in order to increase the intensity of light in the lateral direction of the LED element, a metal film as a reflective layer is arranged on the upper surface of a rectangular parallelepiped glass material that seals the LED element. Similarly, in Patent Documents 2 and 3, a white reflective layer (such as a scattering layer in which titanium oxide is dispersed in resin) is placed in a hole provided in a light guide plate at a position facing an LED element sealed with glass or resin. ) are placed.

Patent Document 4 below discloses a backlight unit including a light guide unit in which a plurality of structures, each including an LED and a light guide, are connected to each other by an adhesive. Each light guide has a recess in the central portion on the side opposite to the exit surface, and an LED as a light source is arranged in the recess of each light guide. The central portion of each light guide opposite to the exit surface located on the optical sheet side is relatively thick compared to the end portions.

JP 2011-211085 A JP 2011-210674 A JP 2010-008837 A JP 2009-152152 A

If the thickness of a light-emitting device including a plurality of light sources represented by LEDs can be made thinner while suppressing luminance unevenness, it is beneficial because a device including the light-emitting device as a backlight can be made smaller.

A light emitting device according to an embodiment of the present disclosure includes a light guide plate including a first surface provided with a plurality of first recesses and a second surface located opposite to the first surface; a light-reflective resin layer positioned on the bottom; and a plurality of light-emitting elements each having a top surface and a side surface, the plurality of light-emitting elements being disposed inside corresponding ones of the plurality of first recesses. and a plurality of wavelength conversion members, wherein the upper surface of each light emitting element is bonded to the light reflective resin layer, and each of the plurality of wavelength conversion members is positioned inside the first concave portion of the light emitting element. covering said side of the

Embodiments of the present disclosure provide a light emitting device, eg, backlight, with reduced thickness.

1 is a perspective view schematically showing an exemplary configuration of a light emitting device according to a first embodiment of the present disclosure; FIG. FIG. 4 is a schematic cross-sectional view showing an exemplary configuration of a light emitting cell; FIG. 4 is a schematic plan view showing an example of the appearance when the light emitting cell is viewed from the normal direction of the upper surface of the light guide plate; FIG. 3 is a schematic enlarged view showing an enlarged view of a light emitting element and its surroundings in FIG. 2; FIG. 4 is a schematic cross-sectional view showing a modification of the light emitting device according to the first embodiment of the present disclosure; 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. 1A to 1D are schematic cross-sectional views for explaining an exemplary manufacturing method of a light emitting device according to a first embodiment of the present disclosure; FIG. FIG. 4 is a schematic cross-sectional view showing another modified example of the light emitting device according to the first embodiment of the present disclosure; FIG. 4A is a schematic cross-sectional view for explaining another exemplary manufacturing method of the light-emitting device according to the first embodiment of the present disclosure; FIG. 4A is a schematic cross-sectional view for explaining another exemplary manufacturing method of the light-emitting device according to the first embodiment of the present disclosure; FIG. 4A is a schematic cross-sectional view for explaining another exemplary manufacturing method of the light-emitting device according to the first embodiment of the present disclosure; FIG. 4A is a schematic cross-sectional view for explaining another exemplary manufacturing method of the light-emitting device according to the first embodiment of the present disclosure; FIG. 4A is a schematic cross-sectional view for explaining another exemplary manufacturing method of the light-emitting device according to the first embodiment of the present disclosure; FIG. 4 is a schematic cross-sectional view showing an exemplary configuration of a light emitting device according to a second embodiment of the present disclosure; FIG. 4A is a schematic cross-sectional view showing a variation of the light emitting device according to the second embodiment of the present disclosure; FIG. 7A is a schematic cross-sectional view for explaining an exemplary method of manufacturing a light-emitting device according to a second embodiment of the present disclosure; FIG. 7A is a schematic cross-sectional view for explaining an exemplary method of manufacturing a light-emitting device according to a second embodiment of the present disclosure; FIG. 7A is a schematic cross-sectional view for explaining an exemplary method of manufacturing a light-emitting device according to a second embodiment of the present disclosure; FIG. 10A is a schematic cross-sectional view for explaining another exemplary method of manufacturing the light emitting device according to the second embodiment of the present disclosure; FIG. 10A is a schematic cross-sectional view for explaining another exemplary method of manufacturing the light emitting device according to the second embodiment of the present disclosure; FIG. 10A is a schematic cross-sectional view for explaining another exemplary method of manufacturing the light emitting device according to the second embodiment of the present disclosure; FIG. 10A is a schematic cross-sectional view for explaining another exemplary method of manufacturing the wavelength conversion member of the light emitting device according to the second embodiment of the present disclosure; FIG. 10A is a schematic cross-sectional view for explaining another exemplary method of manufacturing the wavelength conversion member of the light emitting device according to the second embodiment of the present disclosure; FIG. 11 is a schematic plan view showing an example of a light emitting module according to a third embodiment of the present disclosure; 31 is a plan view schematically showing a configuration in which a set of a plurality of light emitting devices 200 shown in FIG. 30 are further arranged in two rows and two columns; FIG. 3 is a schematic cross-sectional view showing a state in which the light emitting device 200 is connected to the wiring substrate 260; FIG. 4 is a schematic circuit diagram showing an example of a wiring pattern of a wiring layer 160; FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following embodiments are examples, and the light-emitting device and light-emitting module according to the present disclosure are not limited to the following embodiments. For example, numerical values, shapes, materials, steps, order of steps, and the like shown in the following embodiments are merely examples, and various modifications are possible as long as there is no technical contradiction.

The dimensions, shapes, etc. of components shown in the drawings may be exaggerated for clarity, and may not reflect the dimensions, shapes, and size relationships between components in the actual light-emitting device or light-emitting module. be. Also, some elements may be omitted to avoid over-complicating the drawing.

In the following description, constituent elements having substantially the same functions are denoted by common reference numerals, and their description may be omitted. The following description may use terms (eg, "upper", "lower", "right", "left" and other terms that include those terms) that indicate particular directions or positions. However, these terms are used only for clarity of relative orientation or position in the referenced drawings. If the relative direction or positional relationship of terms such as “upper” and “lower” in the referenced drawings is the same, drawings other than the present disclosure, actual products, manufacturing equipment, etc. are the same as the referenced drawings. It does not have to be placement. In the present disclosure, “parallel” includes cases where two straight lines, sides, planes, etc. are in the range of about 0° to ±5°, unless otherwise specified. In the present disclosure, "perpendicular" or "perpendicular" includes cases where two straight lines, sides, planes, etc. are in the range of about 90° to ±5° unless otherwise specified.

(First embodiment)
FIG. 1 shows an exemplary configuration of a light emitting device according to a first embodiment of the present disclosure. The light emitting device 200 shown in FIG. 1 includes a light guide plate 210 having an upper surface 210 a and a layered light reflecting member 220 positioned below the light guide plate 210 . For convenience of explanation, FIG. 1 also shows arrows indicating the X, Y, and Z directions that are orthogonal to each other. Arrows indicating these directions may also be illustrated in other drawings of the present disclosure.

As described in detail below, light-emitting devices according to embodiments of the present disclosure have a repeating structure of multiple units each including at least one light-emitting element. Hereinafter, each unit having a light-emitting element may be referred to as a light-emitting cell for convenience of explanation.

In the configuration illustrated in FIG. 1, the light emitting device 200 includes a total of 16 rectangular light emitting cells 100U. Here, these light emitting cells 100U are arranged in a matrix of 4 rows and 4 columns. The number of light emitting cells 100U included in light emitting device 200 and the arrangement of these light emitting cells 100U are arbitrary, and are not limited to the configuration shown in FIG. Each light emitting cell 100U includes part of the light guide plate 210 and part of the light reflecting member 220 .

The light guide plate 210 has a plurality of light diffusion structures on the upper surface 210a side. These light diffusion structures are provided corresponding to the light emitting cells 100U. In other words, each of the plurality of light emitting cells 100U has a light diffusing structure positioned on the upper surface 210a side of the light guide plate 210 . Here, multiple light diffusing structures are provided in each light emitting cell 100U in the form of multiple recesses 12 . The recesses 12 also have a two-dimensional arrangement corresponding to the arrangement of the light emitting cells 100U in 4 rows and 4 columns. That is, here, the plurality of recesses 12 as the light diffusion structure of the light guide plate 210 has a two-dimensional array of 4 rows and 4 columns on the upper surface 210a. However, the arrangement of the light diffusion structure shown in FIG. 1 is merely an example, and for example, a plurality of concave portions 12 are arranged in correspondence with the light emitting cells 100U being arranged in 1 row and m columns (or n rows and 1 column). They can also be arranged in a straight line.

FIG. 2 schematically shows an exemplary configuration of the light emitting cell 100U. A light-emitting cell 100A shown in FIG. 2 is an example of the above-described light-emitting cell 100U. FIG. 2 schematically shows a cross section when the light emitting cell 100A is cut perpendicular to the upper surface 210a of the light guide plate 210. As shown in FIG. As shown, the light emitting cell 100A includes a light guide plate 110 having an upper surface 110a and a lower surface 110b located opposite to the upper surface 110a, and a light reflecting member 120 located on the lower surface 110b side of the light guide plate 110. Light guide plate 110 and light reflective member 120 are part of light guide plate 210 and light reflective member 220 described with reference to FIG. 1, respectively. 2, the light reflecting member 120 includes a layered base portion 120m covering the lower surface 110b of the light guide plate 110, and a wall portion 120w rising from the base portion 120m toward the upper surface 110a of the light guide plate 110. .

As shown, the light emitting cell 100A further includes a light reflecting resin layer 130, a light emitting element 140A, a wavelength converting member 150A, and a wiring layer 160 on the light reflecting member 120. FIG. Each component of the light emitting cell 100A will be described in more detail below.

[Light guide plate 110]
The light guide plate 110 is a generally plate-shaped member made of thermoplastic resin such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, polyester, thermosetting resin such as epoxy or silicone, or glass. have Among these materials, polycarbonate, in particular, can provide high transparency while being inexpensive. The terms “translucent” and “translucent” in this specification are interpreted to include the ability to diffuse incident light, and are not limited to being “transparent”. The light guide plate 110 may have a light diffusion function, for example, by dispersing a material having a refractive index different from that of the base material.

The light guide plate 110 has a function of diffusing light from the light emitting elements 140A described later and emitting the light from the upper surface 110a. The top surface 110a of the light guide plate 110 is part of the top surface 210a described above. That is, in the present embodiment, the set of upper surfaces 110a constitutes a light-emitting surface from which light is emitted in the light-emitting device 200. FIG.

The light guide plate 110 has a light diffusion structure on the upper surface 110a. The light diffusing structure reflects the light emitted from the light emitting element 140A and incident on the light guide plate 110 at the interface with the air layer, for example, and diffuses the light within the plane of the light guide plate 110 . By providing the light diffusion structure on the upper surface 110a of the light guide plate 110, the luminance in the area of the upper surface 110a other than directly above the light emitting elements 140A is improved, and the brightness of the upper surface 110a of the light guide plate, in other words, on the upper surface of the light emitting cell 100A is improved. Brightness unevenness can be effectively suppressed. That is, the light diffusion structure contributes to thinning the light guide plate 110 . The thickness of the light guide plate 110 is typically about 0.1 mm or more and 5 mm or less, and in particular, according to the embodiment of the present disclosure, it can be set to a range of about 0.5 mm or more and 3 mm or less. .

In the configuration illustrated in FIG. 2, the light diffusing structure is provided on the top surface 110a of the light guide plate 110 in the form of an inverted truncated conical recess 12 including a bottom surface 12b and a side surface 12c. The concave portion 12 reflects light traveling toward the upper surface 110a inside the light guide plate 110 at the interface between the inclined side surface 12c and the air layer. The cross-sectional shape of the bottom surface 12b and the side surface 12c is not limited to a linear shape as shown in the figure, and may be a curved shape or a shape including bends and steps. The interior of the concave portion 12 may be filled with a material having a different refractive index from the material of the light guide plate 110 main body. Alternatively, a light-reflective member such as a reflective film made of metal or the like, a white resin layer, or the like may be arranged on the bottom surface 12b and the side surface 12c.

A specific configuration of the light diffusing structure is not limited to a structure like the concave portion 12 shown in FIG. A specific configuration of the light diffusing structure can be appropriately determined according to the shape and characteristics of the light emitting elements arranged on the lower surface 110b side of the light guide plate 110 . Moreover, even when the light diffusion structure is formed in the shape of a concave portion, the shape of the concave portion is not limited to an inverted truncated cone shape, and can be appropriately changed according to desired optical characteristics. The shape of the concave portion 12 may be, for example, a cone, a polygonal pyramid shape such as a quadrangular pyramid or a hexagonal pyramid, or a polygonal truncated pyramid shape. The depth of the concave portion 12 is, for example, in the range of 0.05 mm or more and 3 mm or less. As the light diffusing structure, instead of the concave portion, a convex portion projecting from the upper surface 110a may be applied.

Light guide plate 110 may be a single layer or may have a laminated structure including a plurality of translucent layers. When laminating a plurality of translucent layers, a layer having a refractive index different from that of the others, such as an air layer, may be interposed between arbitrary layers. By interposing, for example, an air layer between arbitrary layers of the laminated structure, the light from the light emitting element 140A can be diffused more easily, and luminance unevenness can be further reduced.

The light guide plate 110 further has a recess 11 on the lower surface 110b side. In the configuration illustrated in FIG. 2 , a portion of the light emitting element 140A, the light reflecting resin layer 130 and the wavelength conversion member 150A are positioned inside the recess 11 . As can be seen from FIG. 2, typically the recess 11 is located directly below a corresponding one of the plurality of recesses 12 described above. That is, here, in response to the fact that the upper surface 210a of the light guide plate 210 has a plurality of light diffusion structures arranged two-dimensionally, the main surface (lower surface) of the light guide plate 210 opposite to the upper surface 210a has two It has a plurality of recesses 12 that are dimensionally arranged. Of course, depending on the arrangement of the light diffusion structure, the concave portions 12 may be arranged in a row on the lower surface side of the light guide plate 210, for example.

FIG. 3 shows an example of the appearance when the light emitting cell 100A is viewed from the normal direction of the upper surface 210a of the light guide plate 210. As shown in FIG. In the configuration illustrated in FIG. 3, the light emitting cell 100A has a square outline. Therefore, light guide plate 210 as an aggregate of light guide plates 110 of light emitting cell 100A also has a rectangular shape as a whole. Here, the X direction and the Y direction described above correspond to one side and the other side of the rectangular shape of the light guide plate 210, which are orthogonal to each other, respectively (see FIG. 1).

The length of one side of the rectangular shape of the upper surface 210a of the light guide plate 210, which constitutes the light emitting surface of the light emitting device 200, can be, for example, in the range of 1 cm or more and 200 cm or less. In a typical embodiment of the present disclosure, one rectangular side of the upper surface 210a of the light guide plate 210 has a length of 20 mm or more and 25 mm or less.

In the example shown in FIG. 3, the recess 11 provided on the lower surface 110b side of the light guide plate 110 has a square shape. That is, in this example, the recessed portion 11 is a rectangular prism-shaped hole. Thus, the concave portion 11 can have an outer shape similar to the outer shape of the light guide plate 110 . Typically, the center of the concave portion 11 as the first concave portion located on the lower surface 110b side of the light guide plate 110 and the center of the concave portion 12 as the second concave portion located on the upper surface 110a side are substantially aligned.

The length along the diagonal direction of the rectangular bottom surface (or opening) of the recess 11 shown in FIG. be. The length in the diagonal direction of the bottom surface of the quadrangular prism shape may be substantially the same as the diameter of the bottom surface 12b of the recess 12 provided on the upper surface 110a side of the light guide plate 110 . The shape and size of the concave portion 11 can be appropriately determined according to desired optical characteristics.

When the concave portion 11 has a rectangular shape in plan view, it is not essential that one side of the rectangular shape of the concave portion 11 is parallel to one side of the rectangular shape of the light guide plate 110 . For example, the rectangular shape of the concave portion 11 may be inclined by 45° with respect to the rectangular shape of the light guide plate 110 . That is, as schematically shown in FIG. 3, the concave portion 11 is provided on the lower surface 110b of the light guide plate 110 so that each side of the rectangular outer shape of the concave portion 11 is substantially parallel to the diagonal line of the rectangular shape of the light guide plate 110. may As illustrated in FIG. 3, by inclining the rectangular shape of the concave portion 11 by 45° with respect to the rectangular shape of the light guide plate 110, the sides of the rectangular shape of the concave portion 11 and the corners of the rectangular shape of the light guide plate 110 face each other. become.

If the recess 11 has a rectangular shape in plan view, the amount of light emitted from the recess 11 in the direction in which the diagonal lines of the rectangular shape of the recess 11 extend is the same as the direction perpendicular to the sides of the rectangular shape of the recess 11. generally tends to be small compared to the amount of light applied. Therefore, assuming that one side of the rectangular shape of the light guide plate 110 and one side of the rectangular shape of the concave portion 11 are parallel to each other, when the light guide plate 110 is viewed from the side of the upper surface 110a, the luminance at the four corners of the upper surface 110a is can be relatively small. On the other hand, as in the example of FIG. The distance from the rectangular corner to the wall portion 120w of the light reflecting member 120 is increased while enlarging the distance to the portion of the wall portion 120w located at the corner portion of the upper surface 110a (indicated by a double-headed arrow ds in FIG. 3). (indicated by a double arrow dv in FIG. 3) can be reduced.

As will be described in detail later, the wall portion 120w of the light reflecting member 120 has an inclined surface 120d inclined with respect to the lower surface 110b of the light guide plate 110. As shown in FIG. The inclined surface 120 d formed on the wall portion 120 w can function as a reflecting surface that reflects incident light toward the upper surface 110 a of the light guide plate 110 . Therefore, as shown in FIG. 3, by inclining the rectangular shape of the concave portion 11 by 45°, for example, with respect to the rectangular shape of the light guide plate 110, the luminance of the four corners of the rectangular shape of the light guide plate 110 is improved, can relatively reduce the brightness near the center of . In other words, compared to the case where the concave portion 11 is formed so that one side of the rectangular shape of the concave portion 11 is parallel to one side of the rectangular shape of the light guide plate 110, four corners of the rectangular shape of the light guide plate 110 , and near the center of the rectangular side of the light guide plate 110 can be reduced. Therefore, it is possible to suppress luminance unevenness on the upper surface 110 a of the light guide plate 110 .

As for the shape of the concave portion 11 in a plan view, a circular shape may be employed in addition to the rectangular shape shown in FIG. When the recess 11 has a cylindrical shape, for example, the diameter of the cylindrical bottom surface may be substantially the same as the diameter of the truncated conical bottom surface 12b of the recess 12 provided on the upper surface 110a side of the light guide plate 110 .

[Light-reflective resin layer 130]
Refer to FIG. 2 again. In the example shown in FIG. 2, a light reflective resin layer 130 is arranged inside each of the plurality of recesses 11 . As shown in FIG. 2 , the light-reflective resin layer 130 is positioned at the bottom of the recess 11 . Here, the “bottom portion of the concave portion 11” means a portion corresponding to the bottom when the concave portion 11 is regarded as a hole with the lower surface 110b of the light guide plate 110 facing upward. Here, the light-reflective resin layer 130 is disposed on the bottom surface 11b of the surfaces defining the recess 11, which faces the bottom surface 12b of the recess 12 on the side of the upper surface 110a. Thus, in this specification, the terms "bottom" and "bottom" may be used without adhering to the orientation of the light emitting device shown in the drawings. The bottom of the concave portion 11 can also be said to be the ceiling portion of the dome-shaped structure formed on the lower surface 110b side of the light guide plate 110 when the light emitting cell 100A is in the posture shown in FIG.

The light reflective resin layer 130 is made of a light reflective material and positioned between the bottom surface 11b of the recess 11 and the light emitting element 140A. In this specification, "light reflectivity" refers to a reflectance of 60% or more at the emission peak wavelength of the light emitting element 140A. It is more beneficial if the reflectance of the light-reflective resin layer 130 at the emission peak wavelength of the light-emitting element 140A is 70% or more, and even more beneficial if it is 80% or more.

As the material of the light-reflective resin layer 130, for example, a resin material in which a light-reflective filler is dispersed can be used. Silicone resin, phenol resin, epoxy resin, BT resin, polyphthalamide (PPA), or the like can be used as the base material of the resin material for forming the light-reflecting resin layer 130 . As the light-reflecting filler, metal particles, or inorganic or organic material particles having a higher refractive index than the base material in which the light-reflecting filler is dispersed can be used. Examples of light-reflecting fillers are particles of titanium dioxide, silicon oxide, zirconium dioxide, potassium titanate, aluminum oxide, aluminum nitride, boron nitride, mullite, niobium oxide, barium sulfate, or particles such as yttrium oxide and gadolinium oxide. Examples include particles of various rare earth oxides. Beneficially, the light-reflective resin layer 130 has a white color.

By arranging the light-reflective resin layer 130 above the light-emitting element 140A, the light emitted from the light-emitting element 140A and traveling toward the upper surface 110a of the light guide plate 110 near the center of the light guide plate 110 is blocked by the light-reflective resin layer. It can be reflected at 130 . Therefore, it is possible to efficiently diffuse the light emitted from the light emitting element 140A within the plane of the light guide plate 110 . In addition, it is possible to suppress local extremely high luminance in the region of the upper surface 110a of the light guide plate 110 directly above the light emitting element 140A. However, it is not essential that the light reflective resin layer 130 completely shield the light from the light emitting element 140A. In this sense, the light-reflecting resin layer 130 may have a semi-transmissive property of transmitting part of the light from the light emitting element 140A.

[Light emitting element 140A]
FIG. 4 shows an enlarged view of the light emitting element 140A and its periphery in FIG. As shown in FIG. 4, the light emitting element 140A is positioned within the concave portion 11 of the light guide plate 110. As shown in FIG. That is, the light-emitting device 200 includes a plurality of light-emitting elements 140A corresponding to the plurality of concave portions 11 provided in the light guide plate 210 . Each of the plurality of recesses 11 is positioned immediately below one corresponding one of the recesses 12 on the upper surface 110 a side of the light guide plate 110 . Therefore, each of the plurality of light emitting elements 140A is positioned directly below one of the plurality of light diffusion structures provided on the upper surface 210a side of the light guide plate 210 .

A typical example of the light emitting element 140A is an LED. In the configuration illustrated in FIG. 4, the light emitting element 140A has an element body 142 and an electrode 144 located on the side opposite to the upper surface 140a of the light emitting element 140A. The element body 142 includes, for example, a support substrate such as sapphire or gallium nitride, and a semiconductor lamination structure on the support substrate. The semiconductor laminated structure includes an active layer, and an n-type semiconductor layer and a p-type semiconductor layer sandwiching the active layer. The semiconductor laminated structure may contain a nitride semiconductor (In _x Al _y Ga _1-xy N, 0≦x, 0≦y, x+y≦1) capable of emitting light in the ultraviolet to visible region. In this example, the top surface 140a of the light emitting element 140A matches the top surface of the element body 142. As shown in FIG. The electrode 144 includes a pair of positive and negative electrodes and has the function of supplying a predetermined current to the semiconductor laminated structure.

Each of the plurality of light emitting elements 140A provided in the light emitting device 200 may be an element that emits blue light, or may be an element that emits white light. The plurality of light emitting elements 140A may include elements that emit light of different colors. For example, the plurality of light emitting elements 140A may include an element that emits red light, an element that emits blue light, and an element that emits green light. Here, an LED that emits blue light is exemplified as the light emitting element 140A.

Each of the plurality of light emitting elements 140A is joined to a corresponding one of the light reflecting resin layers 130 arranged in each recess 11 provided in the light guide plate 210 . In this example, the light emitting element 140A is fixed at a predetermined position within the recess 11 by bonding its upper surface 140a to the light reflecting resin layer 130 via a bonding member 170 which will be described later. Details of the joint member 170 will be described later.

The top view shape of the light emitting element 140A is typically rectangular. The length of one side of the rectangular shape of the light emitting element 140A is, for example, 1000 μm or less. The vertical and horizontal dimensions of the rectangular light emitting element 140A may be 500 μm or less. A light-emitting element with vertical and horizontal dimensions of 500 μm or less can be easily procured at low cost. Alternatively, the vertical and horizontal dimensions of the rectangular light emitting element 140A may be 200 μm or less. If the length of one side of the rectangular shape of the light emitting element 140A is small, it is advantageous for high-definition image expression, local dimming operation, etc. in application to a backlight unit of a liquid crystal display device. In particular, a light-emitting element having both vertical and horizontal dimensions of 250 μm or less has a small upper surface area, so that the amount of light emitted from the side surfaces of the light-emitting element is relatively large. Therefore, it is easy to obtain a batwing type light distribution characteristic. Here, in a broad sense, the batwing type light distribution characteristic means light emission with high emission intensity at an angle where the absolute value of the light distribution angle is larger than 0°, with the optical axis perpendicular to the upper surface of the light emitting element being 0°. It refers to the light distribution characteristics as defined by the intensity distribution.

If the shape of the light emitting elements 140A in a top view is particularly rectangular, when the plurality of light emitting elements 140A are arranged two-dimensionally with respect to the light guide plate 210, the rotation of the light emitting elements within a plane with respect to a predetermined reference direction, In other words, it becomes easy to find the deviation between the predetermined reference direction and the rectangular shape of the light emitting element, for example, the long side. In addition, the positive electrode and the negative electrode can be formed separately on the opposite side of the upper surface 140a of the light emitting element 140A, and the wiring layer 160 including the wiring connected to the positive electrode and the wiring connected to the negative electrode is formed on the light reflective member 120. It becomes easier to form into Note that it is not essential that the predetermined reference direction is parallel to one side of the rectangular shape of the concave portion 11 or one side of the rectangular shape of the light guide plate 110 .

In the light emitting device 200, the plurality of light emitting elements 140A are arranged two-dimensionally along the X direction and the Y direction. The arrangement pitch of the light emitting elements 140A can be, for example, about 0.05 mm or more and 20 mm or less, and may be in the range of about 1 mm or more and 10 mm or less. Here, the arrangement pitch of the light emitting elements 140A means the distance between the optical axes of the light emitting elements 140A. 140 A of light emitting elements may be arrange|positioned at equal intervals, and may be arrange|positioned at uneven intervals. The arrangement pitch of the light emitting elements 140A may be the same or different between two mutually different directions. The number and arrangement of light emitting elements 140A are not limited to the example described with reference to FIG. 1, and any number and arrangement may be adopted.

[Joining member 170]
The joining member 170 is a translucent member that covers at least part of the side surface 140c of the light emitting element 140A. As schematically shown in FIG. 4, the bonding member 170 typically has a layered portion located between the upper surface 140a of the light emitting element 140A and the light reflecting resin layer 130. As shown in FIG. In this embodiment, one bonding member 170 is arranged on the light-reflective resin layer 130 corresponding to the light-reflective resin layer 130 arranged in each recess 11 . Thereby, the light emitting element 140A can be bonded to the corresponding one of the light reflective resin layers 130 by one of the plurality of bonding members 170 .

As a material of the joining member 170, a resin composition containing a transparent resin material as a base material can be used. The bonding member 170 has a transmittance of, for example, 60% or more with respect to light having an emission peak wavelength of the light emitting element 140A. From the viewpoint of effective use of light, it is beneficial if the transmittance of the bonding member 170 at the peak emission wavelength of the light emitting element 140A is 70% or more, and more beneficial if it is 80% or more.

A typical example of the base material of the joining member 170 is thermosetting resin such as epoxy resin or silicone resin. As the base material of the joining member 170, a silicone resin, a modified silicone resin, an epoxy resin, a phenol resin, a polycarbonate resin, an acrylic resin, a polymethylpentene resin, a polynorbornene resin, or a material containing two or more of these may be used. good. The bonding member 170 may have a light diffusion function, for example, by dispersing a material having a refractive index different from that of the base material.

As described above, the bonding member 170 covers at least part of the side surface 140c of the light emitting element 140A. In addition, the joining member 170 has an outer surface 170c that is an interface with the wavelength converting member 150A, which will be described later. Light emitted from the side surface 140c of the light emitting element 140A and incident on the bonding member 170 is reflected upward from the light emitting element 140A at the position of the outer surface 170c. However, since the light-reflecting resin layer 130 is positioned at the bottom of the recess 11, the light directed upward from the light-emitting element 140A is further reflected by the light-reflecting resin layer 130, and eventually enters the wavelength conversion member 150A. do. The light returned to the wavelength converting member 150A propagates in the in-plane direction of the light guide plate 110 between the base portion 120m of the light reflecting member 120 and the light reflecting resin layer .

The shape of the outer surface 170c of the joint member 170 in a cross-sectional view is not limited to a linear shape as shown in FIG. The shape of the outer surface 170c in a cross-sectional view may be a polygonal shape, a curvilinear shape convex in a direction toward the light emitting element 140A, a curvilinear shape convex in a direction away from the light emitting element 140A, or the like.

[Wavelength conversion member 150A]
In the configuration illustrated in FIG. 4 , the wavelength conversion member 150A occupies a portion of the interior of the recess 11 excluding the light-reflective resin layer 130, the light-emitting element 140A, and the bonding member 170 described above. As schematically shown in FIG. 4 , the wavelength conversion member 150A arranged inside each recess 11 covers the side surface 140c of the light emitting element 140A inside the recess 11 . In this specification, the term "covering" is not limited to the aspect in which the member to be covered and the member to be covered are in direct contact, but also includes aspects in which another member is interposed between them. do. In this example, a joining member 170 is interposed between a portion of the side surface 140c of the light emitting element 140A and the wavelength converting member 150A. However, the wavelength converting member 150A also covers the entire outer surface 170c of the joining member 170, and therefore, it can be said that the entire four side surfaces 140c of the light emitting element 140A are covered with the wavelength converting member 150A.

As illustrated, it is beneficial if the wavelength conversion member 150A is in contact with the light-reflective resin layer 130 inside the recess 11 . Since the light reflective resin layer 130 is arranged adjacent to the wavelength conversion member 150A inside the recess 11, the light emitted from the side surface 140c of the light emitting element 140A and directed toward the wavelength conversion member 150A and the outer surface of the bonding member 170 This is because the light emitted from 170c and directed toward the wavelength conversion member 150A can be reflected at the position of the interface between the light-reflective resin layer 130 and the wavelength conversion member 150A and returned to the wavelength conversion member 150A.

The wavelength conversion member 150A is typically a member in which phosphor particles are dispersed in resin. The wavelength conversion member 150A absorbs at least part of the light emitted from the light emitting element 140A and emits light with a wavelength different from that of the light emitted from the light emitting element 140A. For example, the wavelength conversion member 150A emits yellow light by wavelength-converting part of the blue light from the light emitting element 140A. According to such a configuration, white light is obtained by mixing the blue light that has passed through the wavelength conversion member 150A and the yellow light emitted from the wavelength conversion member 150A. In particular, in this example, wavelength conversion member 150A covers side surface 140c of light emitting element 140A and outer surface 170c of bonding member 170, and is positioned between base portion 120m of light reflecting member 120 and light reflecting resin layer 130. ing. Therefore, the light mixed with the wavelength-converted light can be effectively diffused in the plane of the light guide plate 110, and the effect of suppressing color unevenness can be expected. In this way, the embodiments of the present disclosure are advantageous in homogenizing the light compared to the case where the light is diffused in the light guide plate 110 and then wavelength-converted.

As the resin for dispersing particles such as phosphor, silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, urea resin, phenol resin, acrylic resin, urethane resin, fluorine resin, or two or more of these resins. can be used. From the viewpoint of efficiently introducing light into light guide plate 110 , it is beneficial if the base material of wavelength conversion member 150</b>A has a lower refractive index than the material of light guide plate 110 . A light diffusion function may be imparted to the wavelength conversion member 150A by dispersing a material having a refractive index different from that of the base material in the material of the wavelength conversion member 150A. For example, particles of titanium dioxide, silicon oxide, or the like may be dispersed in the base material of the wavelength conversion member 150A.

A known material can be applied to the phosphor. Examples of phosphors include fluoride-based phosphors such as YAG-based phosphors and KSF-based phosphors, nitride-based phosphors such as CASN, and β-sialon phosphors. YAG phosphors are examples of wavelength conversion substances that convert blue light into yellow light, KSF phosphors and CASN are examples of wavelength conversion substances that convert blue light into red light, and β-SiAlON phosphors are examples of wavelength conversion substances that convert blue light into red light. is an example of a wavelength converting material that converts blue light to green light. The phosphor may be a quantum dot phosphor.

It is not essential that the phosphor contained in the wavelength conversion member 150A be common within the same light emitting cell 100A. It is also possible to use different phosphors dispersed in the base material between different recesses 11 in a single light-emitting cell 100A. For example, among the plurality of recesses 11, a wavelength conversion member that converts incident blue light into yellow light is arranged in some of the recesses 11, and the incident blue light is arranged in some other recesses 11. A wavelength conversion member may be arranged to convert the to green light. Furthermore, a wavelength conversion member that converts incident blue light into red light may be arranged in the remaining concave portion 11 .

[Light Reflective Member 120]
As shown in FIG. 4, the lower surface 110b of the light guide plate 110 and the lower surface 150b of the wavelength converting member 150A can be covered with the light reflecting member 120. As shown in FIG. As described with reference to FIG. 2 , the light reflective member 120 includes a layered base portion 120m located on the lower surface 110b side of the light guide plate 110 . In this example, the base portion 120m of the light reflective member 120 covers not only the lower surface 110b of the light guide plate 110 and the lower surface 150b of the wavelength conversion member 150A, but also the regions other than the electrodes 144 in the light emitting element 140A. That is, as schematically shown in FIG. 4, the base portion 120m of the light reflecting member 120 covers the side surface of the electrode 144, while the lower surface 144b of the electrode 144 is exposed from the lower surface 120b of the light reflecting member 120. there is

As the material of the light reflecting member 120, the same material as the material of the light reflecting resin layer 130 can be applied. Therefore, the light reflecting member 120 functions as a light reflecting layer that reflects incident light toward the light guide plate 110 . Particularly, the base portion 120m of the light reflecting member 120 reflects incident light toward the upper surface 110a of the light guide plate 110 . By covering the lower surface 110b side of the light guide plate 110 with the light reflecting member 120, leakage of light from the lower surface side of the light emitting cell 100A, in other words, from the lower surface 110b of the light guide plate 110 can be suppressed. Therefore, it is possible to improve the light utilization efficiency. Further, by forming the base portion 120m of the light reflecting member 120 in layers on the side of the lower surface 110b of the light guide plate 110, effects such as preventing the light emitting element 140A from falling off from the light guide plate 110 and reinforcing the light guide plate 110 can be expected. .

As shown in FIG. 2, here, the light reflecting member 120 also includes a wall portion 120w protruding from the lower surface 110b side of the light guide plate 110 toward the upper surface 110a side. In the example shown in FIG. 2 , the wall portion 120 w has an inclined surface 120 d that is inclined with respect to the upper surface of the base portion 120 m, that is, the lower surface 110 b of the light guide plate 110 . As can be understood by referring to FIG. 3, the inclined surface 120d surrounds the light emitting element 140A in a rectangular shape.

As already described with reference to FIG. 3, the inclined surface 120d of the wall portion 120w has a function of reflecting incident light toward the upper surface 110a of the light guide plate 110. As shown in FIG. Therefore, by arranging the wall portion 120w having the inclined surface 120d at the peripheral portion of the light guide plate 110, it is possible to prevent the luminance from being relatively lower at the peripheral portion of the light guide plate 110 than at the central portion.

[Wiring layer 160]
The wiring layer 160 is located on the lower surface 120b of the light reflecting member 120 and includes wiring connected to the electrodes 144 of the light emitting elements 140A. The wiring layer 160 is typically a single-layer film or laminated film made of metal such as Cu. The wiring layer 160 has a function of supplying a predetermined current to each light emitting element 140A by being connected to a power source (not shown) or the like.

By providing the wiring layer 160 on the back side of the light emitting device 200, for example, the plurality of light emitting elements 140A in the light emitting device 200 can be electrically connected by the wiring layer 160. FIG. That is, the light-emitting element 140A can be driven, for example, in units of light-emitting devices 200, and as described later, by constructing a light-emitting module by combining a plurality of light-emitting devices 200, the light-emitting module can be locally dimmed. . Of course, the light emitting element 140A may be driven in units of one or more light emitting cells 100A.

According to the embodiment of the present disclosure, a plurality of light emitting elements are arranged, for example, two-dimensionally on the side opposite to the upper surface 210a of the light guide plate 210 that constitutes the light emitting surface, and are optically coupled to the light guide plate 210. It becomes possible to provide a thinner surface light source. In particular, a plurality of recesses 11 are provided on the side opposite to the upper surface 210a of the light guide plate 210, for example, a light-reflecting resin layer 130 is placed in each recess 11, and a light-emitting element is placed on the light-reflecting resin layer 130. Further thinning can be achieved by That is, light from the light-emitting elements can be diffused within the plane of the light guide plate 210 while suppressing an extreme increase in luminance at positions directly above the light-emitting elements due to reflection of light by the light-reflective resin layer 130 . This makes it possible to provide uniform light while being thin.

According to the embodiment of the present disclosure, for example, the thickness of the structure including the light reflecting member 120, in other words, the distance from the lower surface of the electrode of the light emitting element to the upper surface 210a of the light guide plate 210 is set to 5 mm or less, 3 mm, for example. or less than 1 mm. The distance from the bottom surface of the electrode of the light emitting device to the top surface 210a of the light guide plate 210 may be approximately 0.7 mm or more and 1.1 mm or less.

Furthermore, by filling the concave portion 11 with the wavelength conversion member 150A to cover the light emitting elements except for the electrodes with the wavelength conversion member 150A, the mixed light is diffused within the surface of the light guide plate 210, and then the light guide plate 210 can be emitted from the upper surface 210a. Therefore, color unevenness on the upper surface 210a is suppressed, and more uniform white light, for example, can be obtained. As described with reference to FIG. 1 and the like, by providing a light diffusion structure on the upper surface 210a side of the light guide plate 210 so as to correspond to the position of the light emitting element, the light directed to the region directly above the light emitting element is diffused. Due to the structure, the light can be diffused in the plane of the light guide plate 210 more effectively. Therefore, the light diffusion structure provides a more efficient light homogenization effect. For example, by providing a light diffusion structure in the form of a recess on the side of the upper surface 210a of the light guide plate 210, the light directed to the region directly above the light emitting element can be diffused within the plane of the light guide plate 210 by reflection on the side surfaces defining the recess. .

As in the above example, by further providing the light reflecting member 120 on the opposite side of the light guide plate 210 to the upper surface 210a, the light directed toward the lower surface of the light emitting device can be reflected by the light reflecting member 120. Leakage of light from the lower surface side of the light emitting device is suppressed. That is, it is possible to improve the light utilization efficiency. As in the above example, by forming the wall portion 120w having an inclined surface rising toward the upper surface 210a of the light guide plate 210 in the light reflective member 120, the reflection of light at the position of the inclined surface is utilized. , the light can be more efficiently extracted from the upper surface 210a. In particular, when both the shape of the light guide plate 110 of each light emitting cell when viewed from above and the shape of each of the plurality of recesses 11 provided on the lower surface 110b side of the light guide plate 110 when viewed from above are both rectangular, the shape of the recesses 11 is rectangular. Each side of the outline of the shape may be substantially parallel to the diagonal line of the rectangular shape of the light guide plate 110 . By adopting such an arrangement for the concave portion 11, when viewed from the side of the upper surface 110a of the light guide plate 110, the direction of the diagonal line of the rectangular shape of the light guide plate 110 and the direction along the side of the rectangular shape. Brightness differences can be reduced.

As illustrated in FIG. 2 and the like, a wiring layer 160 including wiring electrically connected to the light emitting elements may be provided on the light reflecting member 120 . By adopting such a configuration, it is not necessary to form an electrical connection between each of the plurality of light emitting elements and the wiring substrate, and by connecting a power source to the wiring layer 160, the plurality of light emitting elements can be electrically connected. can be obtained collectively. That is, in the light-emitting device according to the embodiment of the present disclosure, it is easy to form connections between the power supply, driver circuits, etc., and the light-emitting elements. You can get the action.

(First modification)
FIG. 5 shows a variation of the light emitting device according to the first embodiment of the present disclosure. In FIG. 5, similarly to FIG. 4, a light-emitting element and its surroundings are extracted from the light-emitting cell.

The main difference between the light-emitting cell 100B shown in FIG. 5 and the light-emitting cell 100A described with reference to FIGS. 110 in that it is arranged inside the recess 11 .

In the configuration illustrated in FIG. 5, the light emitting element 140B has a reflective film 148 on the top surface 142a of the element body 142. In the configuration shown in FIG. Therefore, in this example, at least a portion of the light-reflective resin layer 130 described above is located between the reflective film 148 of the light-emitting element 140B and the bottom surface 11b forming the bottom of the recess 11 . Each of the plurality of light emitting elements 140B can also be fixed in the corresponding recess 11 via the bonding member 170, similar to the light emitting element 140A described above. In this example, the light-emitting element 140B has its upper surface 140a bonded to the light-reflective resin layer 130 via the bonding member 170 .

The reflective film 148 is, for example, a dielectric multilayer film. The reflective film 148 may be a metal film or a semi-transmissive film of ceramics such as aluminum oxide. By providing the reflective film 148 on the upper surface 142a of the element main body 142, the amount of light directly above the light emitting element 140B can be suppressed, and, for example, a batwing type light distribution characteristic can be realized. That is, the light directly reaching the upper surface 110a of the light guide plate 110 from the upper surface 142a of the element body 142 can be reduced, and the luminance unevenness on the upper surface 110a of the light guide plate 110 can be suppressed more effectively. Note that when the reflective film 148 is provided on the upper surface 142a of the element body 142, the light-reflective resin layer 130 may be omitted. That is, in this embodiment, the light-reflective resin layer 130 is not an essential element.

(Exemplary manufacturing method of light-emitting device)
An exemplary method for manufacturing a light emitting device according to the first embodiment of the present disclosure will now be outlined.

First, as shown in FIG. 6, a light guide plate 210 having, for example, a two-dimensional arrangement of a plurality of recesses 11 on one main surface is prepared. The light guide plate 210 can be formed, for example, by injection molding using a raw material having polycarbonate as a base material. Among the materials described above, thermoplastic resin materials are advantageous because the light guide plate 210 can be efficiently manufactured by injection molding. A light diffusion function may be added to the light guide plate 210 by dispersing a material having a refractive index different from that of the base material in the base material. For forming the light guide plate 210, in addition to injection molding, transfer molding, thermal transfer, or the like can be applied.

In the configuration illustrated in FIG. 6, the light guide plate 210 has a plurality of recesses 12 as a light diffusion structure arranged two-dimensionally on its upper surface 210a side. Further, the light guide plate 210 has a plurality of recesses 11 on a lower surface 210b, which is a main surface opposite to the upper surface 210a. Typically, each of the plurality of recesses 11 is formed immediately below one corresponding one of the plurality of recesses 12 located on the upper surface 210a side. That is, here, the bottom surface 210b of the light guide plate 210 has a two-dimensional arrangement of a plurality of recesses 11, and the bottom surfaces 12b of the recesses 12 on the top surface 210a side and the bottom surfaces 11b of the recesses 11 on the bottom surface 210b side face each other. ing. In the illustrated example, it can be said that the light guide plate 210 is configured by a two-dimensional arrangement of the light guide plates 110 that are a plurality of unit structures each having the concave portions 11 and the concave portions 12 .

Furthermore, in this example, the light guide plate 210 has a plurality of grooves 14 on the lower surface 210b side. Each groove 14 is provided between two unit structures adjacent to each other, in other words, between two light guide plates 110 adjacent to each other. Here, a set of the plurality of grooves 14 forms a grid-like groove structure corresponding to the two-dimensional arrangement of the light guide plate 110 . In this example, each of the plurality of grooves 14 has a V-shaped cross-sectional shape, as schematically shown in FIG.

A structure having recesses (or grooves) on each of the upper surface 210a side and the lower surface 210b side, as illustrated in FIG. It can be obtained by providing it at a predetermined position. According to such a method, since the concave portion on the upper surface 210a side and the concave portion on the lower surface 210b side can be formed collectively, the occurrence of misalignment between the concave portion on the upper surface 210a side and the concave portion on the lower surface 210b side can be prevented. can be avoided. When the light diffusing structure is provided on the upper surface 210 a in the form of the recess 12 , the depth of the recess 11 located on the lower surface 210 b can be appropriately set as long as it does not reach the bottom surface 12 b of the recess 12 . The depth of the concave portion 11 is, for example, in the range of 0.05 mm or more and 4 mm or less, preferably 0.1 mm or more and 1 mm or less.

Next, a light-reflective resin layer 130 is formed on the bottom of each recess 11 . For example, after disposing a resin material in which a light-reflecting filler is dispersed inside each concave portion 11 using a dispenser or the like, the resin material in each concave portion 11 is cured to obtain a resin material as schematically shown in FIG. , a light-reflective resin layer 130 can be formed inside each recess 11 . Alternatively, a plate-like resin sheet is formed from a resin material in which a light-reflecting filler is dispersed, and a plurality of resin pieces having a shape (for example, a square) corresponding to the shape of the concave portion 11 in plan view is formed by cutting, punching, or the like. It may be obtained from a resin sheet. Such a resin piece may be arranged at the bottom of each recess 11 . A resin sheet can be obtained by injection molding, compression molding, transfer molding, or the like.

Next, the light emitting element 140A is bonded to the light reflecting resin layer 130 arranged in each recess 11. Next, as shown in FIG. Here, first, as schematically shown in FIG. 8, a resin composition 170r to be the material of the joining member 170 is applied onto the light-reflective resin layer 130 by a dispenser or the like. Furthermore, the light emitting element 140A is arranged on the applied resin composition 170r. At this time, the light emitting element 140A is arranged on the resin composition 170r so that the upper surface 140a of the light emitting element 140A faces the light reflecting resin layer 130. As shown in FIG. By curing the resin composition 170r, a bonding member 170 is formed from the resin composition 170r, as schematically shown in FIG. be able to. A light emitting element 140B having a reflective film 148 may be fixed to the light reflecting resin layer 130 instead of the light emitting element 140A.

In the step of applying the resin composition 170r onto the light-reflective resin layer 130, by adjusting the viscosity and amount of the resin composition 170r, the resin composition 170r can be seen from the outer edge of the light-reflective resin layer 130 when viewed from above. It is beneficial to avoid reaching If the bonding member has a shape that reaches the side surface 11c that defines the recess 11, light can be directly incident on the light guide plate 210 from the bonding member. Such light can cause luminance unevenness and color unevenness on the light emitting surface. By making the size of the bonding member 170 smaller than the size of the light-reflective resin layer 130 when viewed from the top, the generation of light that directly enters the light guide plate 210 from the bonding member is avoided, thereby preventing uneven brightness and/or uneven color. It can suppress the occurrence.

According to the configuration in which the light-emitting elements 140A are arranged on each of the plurality of light-reflecting resin layers 130 as illustrated in FIG. As a reference, a light emitting element can be arranged at a predetermined position on the lower surface 210b side of the light guide plate 210 . In other words, for example, the light reflecting resin layer 130 can be used for positioning the light emitting elements. In particular, here, since the recess 11 is provided at a position directly below the recess 12, the axis perpendicular to the bottom surface 12b of the recess 12 and passing through the center of the bottom surface 12b is substantially aligned with the optical axis of the light emitting element. It becomes easy to dispose the light emitting element in the recess 11 . By arranging a plurality of light emitting elements with respect to the light guide plate 210 so that the center of the light diffusion structure and the center of the light emitting element substantially coincide when viewed from above, for example, the light from the light emitting element located inside the recess 11 can be can be more uniformly diffused in the plane of the light guide plate 210 by the concave portion 12 as the light diffusion structure.

Next, the wavelength conversion member 150A is arranged inside each recess 11 . For example, a dispenser or the like is used to fill the inside of each recess 11 with a resin composition in which particles such as a phosphor are dispersed, and the resin composition is cured. Thereby, as schematically shown in FIG. 10, the wavelength conversion member 150A covering at least a part of the side surface 140c of the light emitting element 140A can be formed in each recess 11. As shown in FIG. At this time, the surface of the wavelength conversion member 150A may rise above the lower surface 210b of the light guide plate 210, or may become recessed with respect to the lower surface 210b. However, if the electrodes 144 of the light emitting element 140A are not completely covered with the wavelength conversion member 150A, the surface of the wavelength conversion member 150A does not have to be flat and aligned with the lower surface 210b of the light guide plate 210.

As in this example, by providing a plurality of recesses 11 in the lower surface 210b of the light guide plate 210 and forming the wavelength conversion member 150A in each of the recesses 11, a single layer shape can be formed in common with the plurality of light emitting elements 140A. The material for the wavelength conversion member can be saved as compared with a configuration in which the wavelength conversion member is formed by . In the state where the wavelength conversion member 150A is formed, the electrodes 144 of the light emitting element 140A are exposed from the wavelength conversion member 150A as schematically shown in FIG.

Next, as schematically shown in FIG. 11, the light guide plate 210 is formed so as to cover the light emitting elements 140A.
A light reflecting resin layer 120T is formed on the lower surface 210b side of the . For example, after the material of the light-reflective resin layer 120T is applied to the lower surface 210b of the light guide plate 210 so that the electrodes 144 of the light emitting elements 140A are embedded, the applied material is cured. Various methods such as transfer molding, compression molding, spray coating, printing, and potting can be applied to form the light-reflective resin layer 120T. At this time, the inside of the plurality of grooves 14 can also be filled with the material of the light-reflective resin layer 120T. As the material of the light-reflective resin layer 120T, a resin material in which a light-reflective filler is dispersed can be used, like the material of the light-reflective resin layer 130 .

After that, the lower surface of the electrode 144 is exposed from the surface of the light-reflective resin layer 120T by grinding or the like. Thereby, as schematically shown in FIG. 12, the light reflective member 120 can be formed from the light reflective resin layer 120T. By covering the area of the lower surface of the light emitting element 140A excluding the area where the electrode 144 is arranged with the light reflective member 120, leakage of light to the lower surface 120b side of the light reflective member 120 is suppressed and light is extracted. can improve efficiency.

After that, if necessary, a wiring layer 160 is formed on the lower surface 120b of the light reflecting member 120 as schematically shown in FIG. The wiring layer 160 can be formed by, for example, forming a metal film on the lower surface 120b of the light reflecting member 120 by sputtering after forming the light reflecting member 120, and patterning the metal film by, for example, laser ablation. The metal film may be formed on the bottom surface 120b of the light reflecting member 120 in the form of a laminated film. For example, a metal film may be formed on the lower surface 120b of the light reflecting member 120 by sequentially depositing Cu, Ni and Au.

Through the above steps, the light emitting device 200 shown in FIG. 1 is obtained. In the configuration illustrated in FIG. 13, the area of the upper surface 210a of the light guide plate 210 other than the recesses 12 and the area of the lower surface 210b other than the recesses 11 and the grooves 14 are substantially flat surfaces. However, the shape of the upper surface 210a and the lower surface 210b of the light guide plate 210 is not limited to this example. good. For example, areas other than the recesses 12, the recesses 11 and the grooves 14 may be provided with fine uneven patterns, or areas other than the recesses 12, the recesses 11 and the grooves 14 may be roughened.

As can be understood from the exemplary manufacturing process described above, in this embodiment, the light-emitting element 140A (or the light-emitting element 140B) is fixed in advance to the light-emitting cell 100U side, not to the wiring substrate side. , the occurrence of misalignment with the light diffusion structure on the upper surface 110a side of the light guide plate 110 can be suppressed. Furthermore, the light diffused by the wavelength conversion member 150A and/or the light guide plate 110 is emitted from the upper surface of the light emitting cell 100U, that is, the upper surface 110a of the light guide plate 110, so that more uniform light can be realized.

In the example described with reference to FIG. 1, the plurality of light emitting cells 100U are arranged in 4 rows and 4 columns. Therefore, the wall portion 120w (see FIG. 2) of the light reflecting member 120 has a grid-like arrangement surrounding each of the light emitting elements 140A arranged in four rows and four columns. Here, the structure of the plurality of light emitting cells 100U forming the light emitting device 200 is typically common among these light emitting cells 100U. However, it is not essential in the embodiments of the present disclosure that the light emitting device is constructed only with a plurality of light emitting cells having a common structure.

For example, among the 16 light emitting cells 100U arranged in 4 rows and 4 columns, 4 light emitting cells located in the central part of the light emitting surface and 12 light emitting cells in the peripheral part surrounding these cells. The height of the wall portion 120w may be different between them. In particular, in the 12 light emitting cells in the outer peripheral portion, the height of the wall portions 120w located at the positions of the four sides of the rectangular shape that defines the light emitting surface may be relatively increased. By making the wall portion 120w located at the outermost periphery of the light guide plate 210 relatively high, it is possible to improve the brightness at the positions of the four sides of the rectangular shape that defines the light emitting surface. In other words, by varying the height of the wall portion 120w among the plurality of light emitting cells 100U, the difference between the brightness at the periphery of the light guide plate 210 and the brightness at the central portion may be reduced. Alternatively, the configuration of the light diffusion structure, for example, the size of the recesses 12 may be changed between one or more light emitting cells located in the central portion of the light emitting surface and a plurality of light emitting cells located in the outer peripheral portion.

(Second modification)
FIG. 14 is a schematic cross-sectional view showing another modified example of the light emitting device according to the first embodiment of the present disclosure; In FIG. 14, similarly to FIG. 5 and the like, the light-emitting element and its surroundings in the light-emitting cell are shown in an enlarged manner.

A light emitting cell 100C shown in FIG. 14 includes a light emitting element 140B arranged inside the concave portion 11 of the light guide plate 110, as in the example shown in FIG. As already described with reference to FIG. 5, the light emitting element 140B has the reflective film 148 positioned on its upper surface 140a side. The main difference between the light emitting cell 100C and the light emitting cell 100B described with reference to FIG. 5 is that in the light emitting cell 100C shown in FIG. , is formed on a region other than the region facing the upper surface 140a of the light emitting element 140B.

In the example shown in FIG. 14, the reflecting film 148 of the light emitting element 140B is joined to the bottom of the recess 11 by a joining member 170 arranged near the center of the bottom surface 11b of the recess 11. In the example shown in FIG. That is, here, the light emitting element 140B is fixed to the light guide plate 110 without the light reflecting resin layer 130 interposed therebetween. Therefore, the light reflecting resin layer 130 is not located between the bottom surface 11b of the recess 11 and the top surface 140a of the light emitting element 140B. In other words, in this example, the light-reflective resin layer 130 is formed on the bottom surface 11b of the concave portion 11 in a ring shape surrounding the light emitting element 140B in plan view. The top surface 140a of the light emitting element 140B may be in contact with the bottom surface 11b of the recess 11. FIG.

Compared with the light emitting cell 100B shown in FIG. 5, the light emitting cell 100C has a wavelength converting member 150C instead of the wavelength converting member 150A. The point that the wavelength conversion member 150C covers the side surface 140c of the light emitting element 140B inside the recess 11 is the same as the example described with reference to FIG. In addition, since the light reflecting resin layer 130 is formed on the area of the bottom surface 11b of the concave portion 11 other than the area where the reflecting film 148 is joined, light is emitted from the side surface 140c of the light emitting element 140B and the wavelength conversion member is emitted. The light incident on 150C can be diffused in the in-plane direction of the light guide plate 110 and then introduced into the light guide plate 110 . That is, similarly to the examples described so far, the light that has been wavelength-converted by the wavelength conversion member 150C and the light that has passed through the wavelength conversion member 150C can be effectively diffused within the plane of the light guide plate 110. FIG.

In this example, the light reflective resin layer 130 is not arranged directly above the light emitting element 140B. However, since the light-emitting element 140B has the reflective film 148, when the light-emitting device 200 is viewed from the upper surface 110a side of the light guide plate 110, local extremely strong bluishness in the region immediately above the light-emitting element 140B can be avoided. obtain. From the viewpoint of reducing the bluishness in the region immediately above the light emitting element 140B, the ratio of the area of the interface between the bonding member 170 and the light guide plate 110 to the area of the reflective film 148 in plan view should be close to 1. is useful. Alternatively, the bonding member 170 may contain white powder (for example, particles of titanium dioxide) or the like, which is an additive that reflects light. According to the configuration illustrated in FIG. 14, the distance from the lower surface 210b to the upper surface 210a of the light guide plate 210 is reduced to the extent that the light-reflective resin layer 130 is not positioned directly above the light-emitting element 140B, and a thinner light-emitting device can be obtained. It is possible to provide

(Exemplary Manufacturing Method of Light Emitting Device Having Light Emitting Cell 100C)
An exemplary method of manufacturing a light emitting device including the light emitting cell 100C shown in FIG. 14 will now be briefly described. First, the light guide plate 210 is prepared. The light guide plate 210 can be prepared in a manner similar to the example described above with reference to FIG. In this example, the multiple recesses 11 of the light guide plate 210 can have a smaller depth than the example shown in FIG.

Next, as schematically shown in FIG. 15, a resin composition 170r is applied to the bottom surface 11b of each recess 11. Then, as shown in FIG. Furthermore, as schematically shown in FIG. 16, the light emitting element 140B is arranged on the resin composition 170r. At this time, the light emitting element 140B is placed in each recess 11 with the upper surface 140a of the light emitting element 140B, in other words, the side of the reflective film 148 facing the bottom surface 11b of the recess 11 . Thereafter, by curing the resin composition 170 r , the bonding member 170 is formed, and the light emitting element 140 B can be fixed to the bottom of each recess 11 by the bonding member 170 .

Next, using a dispenser or the like, a resin material in which a light-reflecting filler is dispersed is applied to the bottom surface 11 b of each recess 11 . By curing the applied resin material, as schematically shown in FIG. 17, the light reflective resin layer 130 is removed from the bottom surface 11b of the concave portion 11 except for the region where the reflective film 148 of the light emitting element 140B is bonded. can be formed. At this time, the thickness of the light-reflective resin layer 130 can be adjusted by adjusting the amount of the resin material applied to the bottom surface 11 b of each recess 11 . The thickness of the light-reflecting resin layer 130 can be appropriately determined according to the required optical characteristics, and therefore, it goes without saying that the thickness is not limited to the thickness shown in FIG. 14 and the like.

Next, the inside of each recess 11 is filled with the material of the wavelength conversion member 150C, and the filled material is cured. Thereby, as schematically shown in FIG. 18, a wavelength conversion member 150C that covers at least a portion of the side surface 140c of the light emitting element 140B can be formed inside each recess 11. As shown in FIG.

Subsequent steps may be similar to the manufacturing steps described above. That is, the light reflective resin layer 120T is formed on the lower surface 210b side of the light guide plate 210, and the lower surfaces of the electrodes 144 are exposed from the surface of the light reflective resin layer 120T by grinding or the like. Thereby, the light reflective member 120 can be formed from the light reflective resin layer 120T. If necessary, a wiring layer 160 is formed on the lower surface 120b of the light reflecting member 120, as schematically shown in FIG. Through the above steps, a light-emitting device having a plurality of light-emitting cells 100C is obtained.

(Second embodiment)
FIG. 20 shows an exemplary configuration of a light emitting device according to the second embodiment of the disclosure. 20, similarly to FIG. 5, FIG. 14, etc., the light-emitting element and its surroundings in the light-emitting cell are shown in an enlarged manner.

Compared with the light emitting cell 100B described with reference to FIG. 5, the light emitting cell 100D shown in FIG. 20 has a wavelength converting member 150D instead of the wavelength converting member 150A. Similar to the example described with reference to FIGS. 5 and 14, the wavelength conversion member 150D covers the side surface 140c of the light emitting element 140B inside the recess 11. FIG. In this example, part of the wavelength converting member 150D is located between the reflecting film 148 arranged on the upper surface 140a side of the light emitting element 140B and the bottom surface 11b of the recess 11, as schematically shown in FIG. ing. That is, in this example, the wavelength conversion member 150D also covers the upper surface 140a of the light emitting element 140B.

As in this example, part of the wavelength conversion member 150D may be interposed between the reflective film 148 of the light emitting element 140B and the light guide plate 110. FIG. This configuration also provides a surface light source that basically does not require a wiring board, as in the first embodiment. Note that the light-emitting cell 100D does not have the light-reflective resin layer 130 as compared with the light-emitting cell 100B shown in FIG. However, in the illustrated example, the light emitting element 140B has a reflective film 148 on the side of the upper surface 140a, and the upper surface 140a is arranged inside the recess 11 with the upper surface 140a facing the bottom of one corresponding one of the plurality of recesses 11. It is Therefore, the light emitted directly above the light emitting element 140B from the upper surface 142a of the element main body 142 is reduced by the reflective film 148. As a result, when the light guide plate 110 is viewed from the upper surface 110a side, the light directly above the light emitting element 140B is reduced. Extremely high brightness in the region is avoided. That is, as in the first embodiment, it is possible to provide a thin surface light source in which luminance unevenness is suppressed.

(Third modification)
FIG. 21 schematically shows a variation of the light emitting device according to the second embodiment of the present disclosure. Compared with the light emitting cell 100D shown in FIG. 20, the light emitting cell 100E shown in FIG. 21 further has a light reflecting resin layer 130 located between the bottom of the recess 11 and the wavelength conversion member 150D. As in this example, the light-reflecting resin layer 130, at least a part of which is located between the bottom surface 11b of the recess 11 and the wavelength converting member 150D, is further arranged in the recess 11, so that the light guide plate 100 is formed inside the recess 11. Light traveling toward the upper surface 110 a of 110 can be reflected at the position of the light-reflective resin layer 130 . Therefore, the light wavelength-converted by the wavelength converting member 150D can be effectively diffused within the plane of the light guide plate 110. FIG.

(Exemplary Method for Manufacturing a Light-Emitting Device Having Light-Emitting Cell 100D or Light-Emitting Cell 100E)
An exemplary method of manufacturing a light emitting device including the light emitting cell 100D shown in FIG. 20 or the light emitting cell 100E shown in FIG. 21 will now be briefly described.

First, the light guide plate 210 is prepared in the same manner as the examples described so far. Next, as shown in FIG. 22, a dispenser or the like is used to apply a resin composition 150Dr, which is the material of the wavelength conversion member 150D, to the bottom surface 11b of each recess 11. Next, as shown in FIG. At this time, the volume of the resin composition 150Dr introduced into each recess 11 does not fill the entire recess 11, but the volume of the resin composition 150Dr introduced into the recess 11 is the portion of the light emitting element 140B excluding the electrode 144 from the volume of the recess 11. Adjust the amount of the resin composition 150Dr so that it is approximately equal to the volume minus the volume of .

Next, the light emitting element 140B is arranged inside the recess 11 . At this time, by pressing the light emitting element 140B into the uncured resin composition 150Dr, the space between the side surface 11c of the recess 11 and the side surface 140c of the light emitting element 140B is filled with the resin composition 150Dr. By curing the resin composition 150Dr in this state, as schematically shown in FIG. 23, the wavelength conversion member 150D covering the side surface 140c and the upper surface 140a of the light emitting element 140B can be formed inside each recess 11. .

Subsequent steps may be the same as in the first embodiment. For example, after forming the light reflective resin layer 120T on the side of the lower surface 210b of the light guide plate 210, the light reflective member 120 is formed by exposing the lower surface of the electrode 144 from the surface of the light reflective resin layer 120T. Furthermore, as schematically shown in FIG. 24, a wiring layer 160 may be formed on the lower surface 120b of the light reflecting member 120 as required. Through the above steps, the light-emitting device having the light-emitting cell 100D shown in FIG. 20 as a unit is obtained.

If it is desired to obtain a light-emitting device in which the light-emitting cell 100E shown in FIG. 21 is a unit, after preparing the light guide plate 210 and before forming the wavelength conversion member 150D, the same procedure as in the example described with reference to FIG. 7 is performed. Then, the resin material in which the light-reflecting filler is dispersed is placed inside each recess 11, and then the resin material in each recess 11 is cured to form the light-reflecting resin layer 130. FIG. Next, as shown in FIG. 25 , an uncured resin composition 150Dr is applied onto the light-reflective resin layer 130 .

Subsequent steps may be similar to the example described with reference to FIGS. That is, the light emitting element 140B is arranged in the concave portion 11 to which the resin composition 150Dr is applied. By submerging the light emitting element 140B in the resin composition 150Dr, the space between the side surface 11c of the recess 11 and the side surface 140c of the light emitting element 140B is filled with the resin composition, as in the above-described example described with reference to FIG. 150Dr can be filled. In the step of applying the resin composition 150Dr to each recess 11, by adjusting the amount of the resin composition 150Dr placed in the recess 11, the resin composition in the state where the light emitting element 140B is submerged in the resin composition 150Dr The position of the surface of the object 150Dr can be approximately matched with the position of the lower surface 210b of the light guide plate 210. FIG.

After that, the resin composition 150Dr is cured. By curing the resin composition 150Dr, as shown in FIG. 26, the wavelength conversion member 150D covering the side surface 140c and the upper surface 140a of the light emitting element 140B can be formed inside each recess 11 from the resin composition 150Dr.

After that, for example, the light reflecting member 120 is formed on the lower surface 210b side of the light guide plate 210, and the wiring layer 160 is formed on the lower surface 120b of the light reflecting member 120 as necessary. As shown in FIG. 27, a light-emitting device having the light-emitting cell 100E as a unit is obtained through the above steps.

(Other Manufacturing Method of Wavelength Conversion Member 150D)
Alternatively, the wavelength conversion member 150D may be formed as described below. First, the light guide plate 210 is prepared in the same manner as the examples described so far. Next, an uncured resin composition 150Dr is applied to the bottom surface 11b of each recess 11 using a dispenser or the like. Thereafter, the resin composition 150Dr is precured by heating or the like. Thereby, as schematically shown in FIG. 28, the first wavelength conversion layer 150Da can be formed on the bottom of the concave portion 11 .

Next, as shown in FIG. 29, the light-emitting element 140B is arranged on the precured first wavelength conversion layer 150Da. After that, the inside of each concave portion 11 is further filled with an uncured resin composition 150Dr. By curing the first wavelength conversion layer 150Da together with the filled resin composition 150Dr, the side surface 140c and the upper surface 140a of the light emitting element 140B are separated from the first wavelength conversion layer 150Da and the uncured resin composition 150Dr. A covering wavelength conversion member 150</b>D can be formed inside each recess 11 . That is, a structure similar to that shown in FIG. 20 can be obtained. In addition, in the same manner as the example described with reference to FIG. A structure similar to that of the light emitting cell 100E shown in FIG. 21 can be obtained.

(Third Embodiment)
FIG. 30 shows an example of a light emitting module according to the third embodiment of the disclosure. A light-emitting module 300 shown in FIG. 30 includes a two-dimensional array of multiple light-emitting devices 200 . FIG. 30 is an example in which the light emitting devices 200 described above are arranged in 8 rows and 16 columns, and schematically shows the appearance of the two-dimensional arrangement of the light emitting devices 200 as viewed from the upper surface 210 a side of the light guide plate 210 .

The light guide plates 210 of two light emitting devices 200 adjacent in the row direction or column direction are typically in direct contact with each other. However, it is not essential that the two-dimensional array is formed such that the light guide plates 210 of the two adjacent light emitting devices 200 are in direct contact with each other. A direct coupling light guide structure may be interposed. Such a light guide structure can be formed, for example, by applying a translucent adhesive to the side surface of the light guide plate 210 and then curing the applied adhesive. Alternatively, a plurality of light emitting devices 200 are arranged two-dimensionally with a gap between each other, and the region between two light guide plates 210 adjacent to each other is filled with a translucent resin material, and then the resin material is cured. A light structure may be formed. As the material of the light guide structure positioned between the light guide plates 210, the same material as the bonding member 170 described above can be used. Advantageously, a material having a refractive index equal to or greater than that of the material of the light guide plate 210 can be used as the base material of the light guide structure. Light guide plate 210
A light diffusing function may be imparted to the light guide structure located in between.

In the example shown in FIG. 30, the vertical length L and horizontal length W of each light emitting device 200 are, for example, approximately 24.3 mm and 21.5 mm, respectively. Therefore, the arrangement of light emitting devices 200 shown in FIG. 30 is suitable for a screen size of 15.6 inches with an aspect ratio of 16:9. For example, the arrangement of light-emitting devices 200 shown in FIG. 30 can be suitably used for a backlight unit of a laptop computer having a screen size of 15.6 inches. In addition, in a configuration in which a plurality of light emitting devices 200 are combined, there is a possibility that the brightness may be slightly lower immediately above the boundary of the light emitting devices 200 compared to the area on the light guide plate 210 of each light emitting device 200 . However, in application to a backlight unit of a liquid crystal display device, for example, a plurality of optical sheets including a light diffusion sheet and the like are typically interposed between the light emitting device 200 and the liquid crystal panel. Therefore, it can be said that the possibility that the boundary of the light-emitting device 200 is observed as a dark line is low.

According to an embodiment of the present disclosure, the collection of upper surfaces 210a of the light guide plates 210, which are the upper surfaces of the light emitting devices 200, constitutes a light emitting surface. Therefore, by changing the arrangement of the light emitting devices 200 or changing the number of the light emitting devices 200 included in the light emitting module 300, the light emitting module 300 can be easily applied to a plurality of types of liquid crystal panels having different screen sizes. can be done. That is, it is possible to flexibly respond to changes in screen size without redoing optical calculations for the light guide plate 210 and the like in the light emitting device 200 and remanufacturing the mold for forming the light guide plate 210. It is possible. Therefore, the change in screen size does not lead to an increase in manufacturing cost and lead time.

FIG. 31 shows a configuration in which a set of a plurality of light emitting devices 200 shown in FIG. 30 are further arranged in two rows and two columns. In this case, a total of 512 light-emitting devices 200 can constitute a surface light source having an aspect ratio of 16:9 and a screen size of 31.2 inches. For example, the arrangement of the light emitting devices 200 shown in FIG. 31 can be used for backlight units of liquid crystal televisions. As described above, according to this embodiment, it is relatively easy to obtain a large-area light-emitting surface.

According to the method of configuring the light-emitting surface of the light-emitting module 300 by combining a plurality of light-emitting devices 200, it is necessary to redo the design of the optical system or re-manufacture the mold for forming the light guide plate according to the screen size. This makes it possible to flexibly deal with liquid crystal panels of various screen sizes. That is, a backlight unit suitable for the screen size can be provided at low cost and in a short delivery time. In addition, even if there is a light emitting element that does not light up due to disconnection or the like, there is an advantage that the light emitting device including the defective light emitting element can be replaced.

(Electrical connection between multiple light emitting devices 200)
As described with reference to FIG. 2 and the like, on the lower surface 120b of the light reflecting member 120, the wiring layer 160 having electrical connection with the light emitting elements in the light emitting cells may be provided. In such a configuration, electrical connection can be easily formed between the light emitting element in the light emitting device 200 and the power source by connecting the power source or the like to the wiring layer 160 . That is, by connecting a power supply to the wiring layer 160, surface emission can be easily obtained.

FIG. 32 shows a state in which the light emitting device 200 is connected to the wiring substrate 260. FIG. In one embodiment, the light emitting device of the present disclosure can have a wiring substrate 260 as shown in FIG. In the configuration illustrated in FIG. 32 , a wiring substrate 260 has an insulating base material 265 , a first wiring layer 261 and a second wiring layer 262 on the insulating base material 265 , and a plurality of vias 264 . The first wiring layer 261 is provided on one main surface of the insulating base material 265 , and the second wiring layer 262 is provided on the insulating base material 265 .
located on the other major surface of the The first wiring layer 261 and the second wiring layer 262 are electrically connected to each other by vias 264 arranged inside the insulating base material 265 .

The wiring substrate 260 is located on the lower surface side of the light emitting device 200 , that is, on the side opposite to the upper surface 210 a of the light guide plate 210 , and the first wiring layer 261 faces the wiring layer 160 of the light emitting device 200 . The light emitting device 200 is mounted on the wiring board 260 by bonding the wiring layer 160 to the first wiring layer 261 of the wiring board 260 by soldering or the like. According to this embodiment, since the wiring layer 160 having connections with the respective light emitting elements can be provided on the light emitting device 200 side, local dimming or the like can be achieved without forming a complicated wiring pattern on the wiring substrate 260 side. connections can be easily formed. Since the wiring layer 160 can have an area larger than the lower surface of the electrode 144 of each light emitting element, it is relatively easy to form an electrical connection with the first wiring layer 261 . Alternatively, for example, when the light emitting device 200 does not have the wiring layer 160 , the electrodes of the light emitting elements may be connected to the first wiring layer 261 of the wiring board 260 .

FIG. 33 shows an example of the wiring pattern of the wiring layer 160. As shown in FIG. For simplicity, FIG. 33 schematically shows four of the plurality of light emitting devices 200 that can be included in the light emitting module 300 and their electrical connections.

The light emitting module 300 has a wiring layer 160 for each light emitting device 200, and the wiring layer 160 of each light emitting device 200 electrically connects the plurality of light emitting elements 140 included in the light emitting device 200 to each other. Here, the light-emitting element 140 shown in FIG. 33 is the above-described light-emitting element 140A or light-emitting element 140B. In the example shown in FIG. 33, the wiring layer 160 of each light emitting device 200 connects four light emitting elements 140 in series and connects four groups of the light emitting elements 140 connected in series in parallel. there is

As shown in FIG. 33, each of these wiring layers 160 can be connected to a driver 250 that drives the light emitting element 140. FIG. The driver 250 may be arranged on a substrate or the like (for example, a wiring substrate 260) supporting the light emitting modules and electrically connected to the wiring layer 160, or may be arranged on a substrate separate from the substrate or the like supporting the light emitting modules. and electrically connected to the wiring layer 160 . With such a circuit configuration, a local dimming operation is possible for each light emitting device 200 including 16 light emitting elements 140 . Of course, the connection of the plurality of light emitting elements 140 by the wiring layer 160 is not limited to the example shown in FIG. Alternatively, the light-emitting elements 140 included in the light-emitting device 200 may be divided into a plurality of groups, and the plurality of light-emitting elements 140 may be electrically connected so that the light-emitting elements 140 can be driven in units of groups including the plurality of light-emitting elements 140. good.

As described above, according to the embodiments of the present disclosure, it is possible to provide a light source device that can flexibly adapt to various screen sizes while further reducing the thickness. In each of the embodiments described above, the arrangement of the light emitting elements 140A and 140B and the light emitting devices 200 shown in the drawings is merely an example, and the number and arrangement of the light emitting devices 200 in the light emitting module, for example, can be set arbitrarily. Moreover, each embodiment described above is merely an example, and various combinations are possible as long as there is no technical contradiction.

Embodiments of the present disclosure are useful for various illumination light sources, vehicle light sources, display light sources, and the like. In particular, it can be advantageously applied to a backlight unit directed to a liquid crystal display device. The light-emitting device according to the embodiment of the present disclosure can be suitably used as a backlight for a display device of a mobile device, which requires a strict thickness reduction, a surface light-emitting device capable of local dimming control, and the like.

11 (first) concave portion 12 (second) concave portion 14 groove portion 100A to 100E, 100U light emitting cell 110 light guide plate 110a upper surface of light guide plate 110b lower surface of light guide plate 120 light reflective member 120T light reflective resin layer 120m light reflective member base portion 120w wall portion of light-reflective member 130 light-reflective resin layer 140, 140A, 140B light-emitting element 140a upper surface of light-emitting element 140c side surface of light-emitting element 144 electrode 148 reflective film 150A, 150C, 150D wavelength conversion member 160 wiring layer 200 Light emitting device 210 light guide plate 210a upper surface of light guide plate 210b lower surface of light guide plate 220 light reflective member 250 driver 260 wiring board 300 light emitting module

Claims (11)

a light guide plate including a first surface provided with a plurality of first recesses and a second surface located opposite to the first surface;
A plurality of light emitting elements each having an upper surface, each arranged inside the first recess with the upper surface facing the bottom of a corresponding one of the plurality of first recesses. a light-emitting element of
a plurality of wavelength conversion members each positioned inside a corresponding one of the plurality of first recesses; ,
a second light reflective member positioned on the first surface side of the light guide plate;
with
each of the plurality of light emitting elements has an electrode provided on the side opposite to the upper surface;
The second light reflective member covers at least a region other than the electrodes of the light emitting elements on the first surface side of the light guide plate,
the second surface of the light guide plate has a plurality of second recesses located on opposite sides of the plurality of first recesses;
each of the plurality of second recesses has a bottom surface and a side surface that is inclined with respect to the second surface;
each of the first recesses has a bottom surface facing a corresponding bottom surface of the plurality of second recesses;
The light-emitting device, wherein each of the plurality of wavelength conversion members is in contact with the bottom surface of the first recess and the top surface of the light-emitting element. 2. The method according to claim 1, wherein the width of the wavelength conversion member in each first concave portion is larger than the width of the light emitting element in a cross-sectional view perpendicular to the normal direction of the second surface of the light guide plate. Luminescent device. 3. The light emitting device according to claim 1, wherein, in a cross section perpendicular to said second surface of said light guide plate, the width of the bottom surface of said second recess is smaller than the width of the corresponding bottom surface of said first recess. 4. The light emitting device according to any one of claims 1 to 3, further comprising a first light reflecting member positioned on the bottom surface and side surfaces of each second recess. 5. The light emitting device according to claim 4, wherein the inside of each second recess is filled with the first light reflecting member. 6. The light-emitting device according to claim 1, wherein each light-emitting element has a reflective film on the upper surface side. 7. The wiring layer according to any one of claims 1 to 6 , further comprising a wiring layer located on the lower surface of said second light reflecting member opposite to said first surface of said light guide plate and electrically connected to said electrode. The light- emitting device according to (1). The light emitting device according to any one of claims 1 to 7, wherein the light guide plate has a rectangular outer shape when viewed from above. The external shape of each first recess in a top view is rectangular,
9. The light emitting device according to claim 8 , wherein each side of the rectangular outline of each first recess is substantially parallel to the diagonal line of the rectangular shape of the light guide plate. 10. The second light reflecting member has a wall portion that protrudes from the first surface side toward the second surface side and has a wall portion that includes an inclined surface surrounding each light emitting element. The light-emitting device according to any one of 1. A light-emitting module comprising a plurality of light-emitting devices according to claim 1 and having a two-dimensional arrangement of the light-emitting devices.

Images