Light-emitting module

Abstract

The present invention provides a light-emitting module that suppresses uneven brightness and further reduces thickness. The light-emitting module includes: a light guide plate (110A) having an upper surface (110a) provided with a first hole portion (10A) and a lower surface (110b) on the side opposite to the upper surface; a light-emitting element (120) opposed to the first hole portion and disposed on the lower surface side of the light guide plate; the upper surface of the light guide plate has a first region (111A) including a plurality of convex portions (110d, 110e) or concave portions (110f), and when viewed from above, the proportion of the plurality of convex portions or concave portions per unit area increases concentrically with the light-emitting element as the center.

Description

Technical Field

[0001] The present disclosure relates to a light-emitting module. Background Art

[0002] The following Patent Document 1 discloses a backlight device composed of a plurality of backlight units each having a light guide plate. The light guide plate of each backlight unit has a recess in the central portion on the side opposite to the light-emitting surface, and an LED is disposed in the recess. These plurality of backlight units are arranged such that the light-emitting surfaces of the light guide bodies form the same plane, and the backlight device is integrally constituted. In the technology described in Patent Document 1, by disposing an optical sheet having a plurality of lens portions on the light-emitting surface side of the light guide plate of each backlight unit, and further interposing a light reflection layer having a plurality of openings between the lens portion and the light guide body, the light uniformity is improved. In addition, Patent Document 1 discloses a technique of expanding the lens portion as it is away from the LED.

[0003] The following Patent Document 2 discloses an optical unit in which a plurality of optical elements are disposed on the upper surface side of a plurality of LEDs arranged on a substrate. In this optical unit, the plurality of LEDs are respectively located inside holes provided in the surfaces of the corresponding optical elements on the side opposite to the light-emitting surface. In the optical unit of Patent Document 2, a concave shape is formed directly above the LED in the light-emitting surface of each optical element, and in addition, a lens array is formed so as to surround the central portion where the concave shape is formed in the light-emitting surface. Patent Document 2 describes a technique that a light diffusion portion, a reflection portion, or a light shielding portion may be provided inside the concave shape.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-150940

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2009-063684 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] It is beneficial to be able to suppress brightness unevenness and to make the thickness of a light-emitting module including a plurality of light sources typified by LEDs thinner. By thinning the light-emitting module, it is possible to make, for example, a device including the light-emitting module as a backlight smaller.

[0010] Technical Solution for Solving the Problems

[0011] The light-emitting module according to an embodiment of the present disclosure includes: a light guide plate having an upper surface provided with a first hole portion and a lower surface opposite to the upper surface; a light-emitting element disposed opposite to the first hole portion and on the lower surface side of the light guide plate; the upper surface of the light guide plate has a first region including a plurality of convex portions or concave portions, and in a plan view, the proportion of the plurality of convex portions or concave portions per unit area increases concentrically with the light-emitting element as the center.

[0012] Advantages of the Invention

[0013] According to an embodiment of the present disclosure, a thin light-emitting module with improved light uniformity is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a schematic perspective view showing an exemplary structure of a surface light source according to an embodiment of the present disclosure.

[0015] Figure 2 is schematically showing related to Figure 1 FIG. is a schematic cross-sectional view and an exemplary external appearance view observed from the upper surface side of the light guide plate of an example related to the light-emitting module shown.

[0016] Figure 3 is an enlarged view showing Figure 2 FIG. is a schematic enlarged view of the light-emitting element and its periphery in the cross-section shown.

[0017] Figure 4 FIG. is a schematic plan view showing another example of the external appearance when observing the light-emitting module from the normal direction of the upper surface of the light guide plate, and is a view showing an example in which the rectangular shape of the opening of the second hole portion provided on the lower surface side of the light guide plate is inclined by 45° with respect to the rectangular shape of the light guide plate.

[0018] Figure 5 FIG. is a schematic plan view showing another example of a light guide plate having a plurality of convex portions on the upper surface.

[0019] Figure 6 FIG. is a schematic plan view showing still another example of a light guide plate having a plurality of convex portions on the upper surface.

[0020] Figure 7 is showing the connection of Figure 1 FIG. is a schematic cross-sectional view of an example in which the surface light source shown is connected to a wiring substrate.

[0021] Figure 8 FIG. is a view showing an example of a wiring pattern of a wiring layer formed on the surface light source side.

[0022] Figure 9 is showing a two-dimensional arrangement of a plurality of Figure 1Schematic top view of an example of a surface light source shown.

[0023] Figure 10 It shows arranging Figure 9 a combination of a plurality of surface light sources shown further arranged in 2 rows and 2 columns. Schematic top view of the structure.

[0024] Figure 11 It is a schematic top view of a light emitting module according to another embodiment of the present disclosure, and is a diagram showing another example of a plurality of convex portions that can be provided in a first region of a light guide plate.

[0025] Figure 12 It is a diagram schematically showing a cross section of a light emitting module according to still another embodiment of the present disclosure. Figure 13 It is a diagram schematically showing a cross section of a light emitting module according to still another embodiment of the present disclosure. Figure 14 It is a diagram schematically showing a cross section of a light emitting module according to still another embodiment of the present disclosure. Figure 15 It is a diagram schematically showing a cross section of a light emitting module according to still another embodiment of the present disclosure.

[0026] Explanation of reference numerals

[0027] 10, 10A, 10B First hole portion

[0028] 10a Opening of the first hole portion

[0029] 11A First part of the first hole portion

[0030] 11c First side surface of the first hole portion

[0031] 12A Second part of the first hole portion

[0032] 12a Opening of the second part

[0033] 12c Second side surface of the second part

[0034] 20 Second hole portion

[0035] 100, 100A~100H Light emitting module

[0036] 100U, 100T Light emitting body

[0037] 110A~110H Light guide plate

[0038] 110a Upper surface of the light guide plate

[0039] 110b Lower surface of the light guide plate

[0040] 110d, 110e (Multiple) convex portions

[0041] 110f (multiple) concave portions

[0042] 111A to 111G First regions

[0043] 111Ba, 111Ca Outer regions of the first regions

[0044] 111Bb, 111Cb Inner regions of the first regions

[0045] 112B, 112D Second regions

[0046] 120 Light-emitting element

[0047] 124 Electrodes of the light-emitting element

[0048] 130 Reflective resin layer

[0049] 140 First light reflection member

[0050] 170 Second light reflection member

[0051] 140s Inclined surface

[0052] 150, 150A Wavelength conversion member

[0053] 160 First bonding member

[0054] 190 Second bonding member

[0055] 180 Wiring layer

[0056] 200 Surface light source

[0057] 210 Light guide plate

[0058] 240 Light reflection member

[0059] 250 Driver

[0060] 260 Wiring substrate

[0061] 300, 400 Surface light sources Detailed implementation manners

[0062] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following embodiments are merely illustrative, and the light-emitting module of the present disclosure is not limited to the following embodiments. For example, the numerical values, shapes, materials, steps, order of steps, etc. shown in the following embodiments are merely examples, and various changes can be made as long as there is no technical contradiction. Each of the embodiments described below is merely illustrative, and various combinations can be made as long as there is no technical contradiction.

[0063] The dimensions, shapes, etc. of the components shown in the drawings are sometimes exaggerated for ease of understanding, and there are cases where they do not reflect the actual dimensions, shapes, and size relationships between the components of the light-emitting module. In addition, in order to avoid making the drawings too complex, the illustration of some components is sometimes omitted.

[0064] In the following description, components having substantially the same function are denoted by common reference numerals, and the description may sometimes be omitted. In the following description, terms indicating a specific direction or position (e.g., "up", "down", "right", "left", and other terms including these terms) are sometimes used. However, these terms are merely used for ease of understanding the relative direction or position in the reference drawings. If the relative direction or position relationship based on terms such as "up" and "down" in the reference drawings is the same, in drawings other than the present disclosure, actual products, manufacturing apparatuses, etc., the same configuration as the reference drawings may not be adopted. In the present disclosure, the term "parallel" means that, unless otherwise specified, it includes the case where two straight lines, sides, surfaces, etc. are within the range of about 0° ± 5°. In addition, in the present disclosure, the term "perpendicular" or "orthogonal" means that, unless otherwise specified, it includes the case where two straight lines, sides, surfaces, etc. are within the range of about 90° ± 5°.

[0065] (Embodiment of surface light source)

[0066] Figure 1 An exemplary structure of a surface light source showing an embodiment of the present disclosure. Figure 1 The surface light source 200 shown includes: a light guide plate 210 having an upper surface 210a, and a layered light reflection member 240 located below the light guide plate 210. It should be noted that for ease of explanation, in Figure 1 arrows indicating the X direction, Y direction, and Z direction that are orthogonal to each other are shown in the figure. In other drawings of the present disclosure, arrows indicating these directions may also be shown.

[0067] The surface light source 200 as a whole is plate-shaped, and the upper surface 210a of the light guide plate 210 that constitutes the light-emitting surface of the surface light source 200 typically has a rectangular shape. Here, the above-mentioned X direction and Y direction respectively coincide with one side and the other side of the rectangular shape of the light guide plate 210 that are orthogonal to each other. The length of one side of the rectangular shape of the upper surface 210a is, for example, in the range of 1 cm or more and 200 cm or less. In a typical embodiment of the present disclosure, one side of the rectangular shape of the upper surface 210a of the light guide plate 210 has a length of 20 mm or more and 25 mm or less. The longitudinal and lateral lengths of the rectangular shape of the upper surface 210a are, for example, about 24.3 mm and 21.5 mm, respectively.

[0068] In Figure 1In the exemplary structure, the surface light source 200 is an aggregate of a plurality of light-emitting modules 100 each including at least one light-emitting element. As Figure 1 shown in the schematic diagram of, in this example, the surface light source 200 includes a total of 16 light-emitting modules 100 arranged two-dimensionally. Here, these 16 light-emitting modules 100 are arranged in 4 rows and 4 columns. The number of light-emitting modules 100 included in the surface light source 200 and the arrangement of these light-emitting modules 100 are arbitrary and are not limited to the Figure 1 shown structure.

[0069] As Figure 1 shown, each light-emitting module 100 has a first hole portion 10, and an opening located on the upper surface 210a of the light guide plate 210 is included in a part of the first hole portion 10. As will be described in detail later, the light-emitting element of each light-emitting module 100 is arranged at a position substantially directly below the first hole portion 10. Corresponding to the fact that the light-emitting modules 100 are arranged in 4 rows and 4 columns in this example, the light-emitting elements are arranged in 4 rows and 4 columns along the X direction and the Y direction. The arrangement pitch of the light-emitting elements can be set, for example, to be about 0.05 mm or more and 20 mm or less, or can also be in the range of about 1 mm or more and 10 mm or less. Here, the arrangement pitch of the light-emitting elements refers to the distance between the optical axes of the light-emitting elements. The light-emitting elements can be arranged at equal intervals or can be arranged at unequal intervals. The arrangement pitch of the light-emitting elements can be the same or different between two different directions.

[0070] Figure 2 Shows an example of the light-emitting module 100, namely the light-emitting module 100A. In Figure 2 , in one figure, schematically shown together are: the cross-section when the light-emitting module 100A is cut perpendicularly to the upper surface 210a of the light guide plate 210 near the center of the light-emitting module 100A; the exemplary appearance of the light-emitting module 100A when observed perpendicularly to the upper surface 210a from the upper surface 210a side of the light guide plate 210.

[0071] The light-emitting module 100A includes a light guide plate 110A and a light-emitting element 120. The light guide plate 110A has an upper surface 110a provided with a first hole portion 10A and a lower surface 110b located on the side opposite to the upper surface 110a. The light guide plate 110A is a Figure 1 part of the light guide plate 210 shown in, and the first hole portion 10A of the light guide plate 110A is a Figure 1One of the plurality of first hole portions 10 shown. It should be noted that the light guide plate 110A can be formed in the surface light source 200 as a single light guide plate continuous between two adjacent light emitting modules 100A. However, for example, there is also a case where, since each light emitting module 100A has an independent light guide plate 110A, a clear boundary can be confirmed between the light guide plates 110A of the two light emitting modules 100A in the surface light source 200.

[0072] In Figure 2 In the illustrated structure, the light emitting module 100A further has a first light reflecting member 140 on the lower surface 110b side of the light guide plate 110A. The first light reflecting member 140 is Figure 1 a part of the light reflecting member 240 shown. In this example, the first light reflecting member 140 includes a layered base portion 140n and a wall portion 140w that stands up from the lower surface 110b side of the light guide plate 110A toward the upper surface 110a side. The wall portion 140w has an inclined surface 140s that surrounds the light emitting element 120. Figure 2 The outermost rectangle B in the dashed rectangle shown in the lower part of

[0073] represents the position of the inner edge of the wall portion 140w. Here, an example where the inner edge of the wall portion 140w is rectangular is shown, but the inner edge of the wall portion 140w can also be other shapes such as a circular shape or an elliptical shape. Similar to the light guide plate 110A, the first light reflecting member 140 is formed in the surface light source 200 so as to be continuous across two adjacent light emitting modules 100A.

[0074] In the light emitting module 100A, the light emitting element 120 is disposed on the lower surface 110b side of the light guide plate 110A so as to face the first hole portion 10A provided on the upper surface 110a of the light guide plate 110A. In Figure 2 the example shown, a second hole portion 20 is provided on the lower surface 110b side of the light guide plate 110A, and the light emitting element 120 is located inside the second hole portion 20 in a plan view. The optical axis of the light emitting element 120 substantially coincides with the center of the first hole portion 10A. Here, the light emitting element 120 is disposed on the lower surface 110b side of the light guide plate 110A in the form of a light emitting body 100U, and a part of the light emitting body 100U includes the light emitting element 120. As will be described later, the light emitting body 100U may further include a wavelength conversion member and the like in addition to the light emitting element 120.

[0075] At least a part of the upper surface 110a of the light guide plate 110A has a first region 111A in which a plurality of convex portions or concave portions are formed. The first region 111A is located in a region of the upper surface 110a that does not overlap with the first hole portion 10A. In Figure 2 In the example shown, a plurality of convex portions 110d are arranged in the first region 111A.

[0076] By providing, for example, a plurality of convex portions 110d in a region of the surface on the upper surface 110a side of the light guide plate 110A that does not overlap with the first hole portion 10A, light from the light-emitting element 120 that is introduced into the inside of the light guide plate 110A from the lower surface 110b side of the light guide plate 110A can be efficiently extracted from the first region 111A. That is, the brightness of the first region 111A can be relatively increased when viewed from the normal direction of the upper surface 110a of the light guide plate 110A.

[0077] In this example, as Figure 2 shown in the lower part of, the first region 111A occupies the entire region of the upper surface 110a that does not overlap with the first hole portion 10A, and the plurality of convex portions 110d are formed in a plurality of points in the first region 111A. It should be noted that Figure 2 is only a schematic diagram for explaining the structure of the upper surface 110a of the light guide plate 110A, and the number or shape of the plurality of convex portions 110d, etc. may not be strictly consistent between the sectional view and the plan view. The same situation also exists in other drawings of the present disclosure.

[0078] As Figure 2 shown in the schematic diagram, the proportion of the convex portions 110d per unit area in the first region 111A increases concentrically with the light-emitting element 120 as the center. In this example, the plurality of convex portions 110d each have a circular shape in plan view, and the diameter of the circular shape of the convex portion 110d increases as it moves away from the center of the light guide plate 110A. More specifically, compared with the convex portions 110d located in the region sandwiched between the imaginary circle R1 centered on the position of the light-emitting element 120 drawn with a dotted line in Figure 2 and the opening 10a of the first hole portion 10A, the convex portions 110d located in the region sandwiched between the circle R1 and the imaginary circle R2 having a diameter larger than that of the circle R1 have a larger diameter. Moreover, the diameter of the convex portions 110d located in the outer region of the circle R2 among the plurality of convex portions 110d is larger than the diameter of the convex portions 110d located in the region sandwiched between the circle R1 and the circle R2. From the Figure 2 structure shown, the diameters of the plurality of convex portions 110d do not need to increase uniformly as they move away from the light-emitting element 120.

[0079] As Figure 2As shown, according to the structure in which the proportion of the plurality of convex portions 110d per unit area in the first region 111A increases concentrically with the light-emitting element 120 as the center, the light emitted from a position far from the light-emitting element 120 can be relatively increased. For example, in this example, the plurality of convex portions 110d disposed near the four corners of the upper surface 110a of the light guide plate 110A have the largest diameter among the convex portions 110d provided in the first region 111A. Therefore, compared with other regions of the first region 111A, the brightness near the four corners of the upper surface 110a of the light guide plate 110A can be relatively increased. As a result of increasing the brightness of the region that is likely to be relatively dark, both the increase in the thickness of the light guide plate 110A can be suppressed, and the brightness unevenness can be more effectively suppressed.

[0080] Next, each component of the light-emitting module 100A will be described in more detail.

[0081] [Light guide plate 110A]

[0082] The light guide plate 110A has a function of diffusing the light from the light-emitting element 120 and emitting it from the upper surface 110a. In the present embodiment, the set of the upper surfaces 110a of the plurality of light guide plates 110A constitutes the light-emitting surface of the surface light source 200.

[0083] The light guide plate 110A is a substantially plate-like member formed of a thermoplastic resin such as acrylate, polycarbonate, cyclic polyolefin, polyethylene terephthalate, polyester, a thermosetting resin such as epoxy resin, silicone resin, or glass, and has translucency. Among these materials, polycarbonate is particularly inexpensive and can provide high transparency. It should be noted that the terms "translucency" and "transmitting light" in this specification are interpreted to also include diffusivity of incident light and are not limited to "transparent". The light guide plate 110A can also have a light diffusion function by, for example, dispersing a material having a refractive index different from that of the base material.

[0084] The first hole portion 10A provided on the upper surface 110a of the light guide plate 110A has a function of reflecting the light emitted from the light-emitting element 120 and introduced from the lower surface 110b side of the light guide plate 110A and diffusing it in the plane of the light guide plate 110A. In this example, the inside of the first hole portion 10A is not filled with resin or the like. In other words, an air layer is formed inside the first hole portion 10A. The first hole portion 10A can also be filled with a material having a refractive index lower than that of the light guide plate 110A.

[0085] For example, by providing such a light diffusion structure on the light guide plate 110A in the manner of the first hole portion 10A, the brightness in the region other than directly above the light emitting element 120 in the upper surface 110a can be increased. That is, uneven brightness in the upper surface of the light emitting module 100A can be suppressed, and the first hole portion 10A as the light diffusion structure contributes to the thinning of the light guide plate 110A. The thickness of the light guide plate 110A, that is, the distance from the lower surface 110b to the upper surface 110a is typically about 0.1 mm or more and 5 mm or less. According to an embodiment of the present disclosure, the thickness of the light guide plate 110A can also be set in the range of about 750 μm.

[0086] Here, the shape of the side surface 10c of the first hole portion 10A in cross section is substantially linear. However, the shape of the side surface 10c in cross section is not limited to a linear shape, and may also be a shape including bends and / or steps, or a curved shape, etc. When the shape of the side surface 10c in cross section is a curved shape, particularly a convex curved shape bulging toward the inside of the first hole portion 10A, it is easy to diffuse light to a position far from the center of the light guide plate 110A, which is advantageous from the viewpoint of obtaining uniform light on the upper surface 110a side.

[0087] The specific shape of the first hole portion 10A is not limited to Figure 2 the illustrated shape. The specific structure of the first hole portion 10A as the light diffusion structure can be appropriately determined according to the shape and characteristics of the light emitting element disposed on the lower surface 110b side of the light guide plate 110A. The shape of the first hole portion 10A can also be, for example, a cone, or a pyramid shape such as a quadrangular pyramid or a hexagonal pyramid, or a frustum of a pyramid shape.

[0088] The depth of the first hole portion 10A is, for example, in the range of 300 μm or more and 400 μm or less. When the first hole portion 10A has Figure 2 and Figure 3 the frustum of an inverted cone shape including the bottom surface 10b as shown, compared with the case where the first hole portion 10A has an inverted cone shape, it is possible to suppress a decrease in the volume of the first hole portion 10A and reduce the depth of the first hole portion 10A. That is, the light emitting module can be made thinner. The diameter of the opening 11a of the first hole portion 10A is, for example, about 3 mm.

[0089] The light guide plate 110A can be a single layer or can have a laminated structure including a plurality of light transmissive layers. In the case of laminating a plurality of light transmissive layers, a layer having a refractive index different from other layers such as an air layer can also be interposed between any layers. By interposing, for example, an air layer between any layers of the laminated structure, it is easy to further diffuse the light from the light emitting element 120, and uneven brightness can be further reduced.

[0090] In the illustrated example, the light guide plate 110A has a second hole portion 20 at a position facing the first hole portion 10A on the lower surface 110b side. A light emitting body 100U including a light emitting element 120 is located inside the second hole portion 20. Figure 3 is an enlarged view showing Figure 2 the light emitting element 120 and its surroundings in the cross section shown. As Figure 3 shown, here, in addition to the light emitting element 120, the light emitting body 100U includes a plate-shaped wavelength conversion member 150, a first bonding member 160, and a second light reflecting member 170. The light emitting body 100U is bonded to the position of the second hole portion 20 of the light guide plate 110A through a second bonding member 190.

[0091] As Figure 2 shown, the second hole portion 20 has, for example, a frustum of a quadrangular pyramid shape. Typically, the center of the second hole portion 20 on the lower surface 110b side of the light guide plate 110A substantially coincides with the center of the first hole portion 10A on the upper surface 110a side. The length of the opening 20a of the second hole portion 20 formed on the lower surface 110b of the light guide plate 110A along the diagonal direction of the rectangular shape may be set to, for example, 0.05 mm or more and 10 mm or less, preferably 0.1 mm or more and 1 mm or less.

[0092] When the shape of the second hole portion 20 in plan view is a rectangular shape, as Figure 2 shown, the second hole portion 20 may be formed on the lower surface 110b of the light guide plate 110A such that one side of its rectangular shape is parallel to one side of the rectangular shape of the light guide plate 110A. Alternatively, the second hole portion 20 may be formed on the lower surface 110b of the light guide plate 110A so as to be inclined with respect to one side of the rectangular shape of the light guide plate 110A.

[0093] Figure 4 An example showing that the rectangular shape of the opening 20a of the second hole portion 20 is inclined by 45° with respect to the rectangular shape of the light guide plate 110A is shown. As Figure 4 shown, by forming the second hole portion 20 such that each side of the rectangular shape of the opening 20a is substantially parallel to the diagonal of the rectangular shape of the light guide plate 110A, the four side surfaces of the second hole portion 20 face the corners of the rectangular shape of the light guide plate 110A. That is, both the distance from the side surface of the second hole portion 20 to the corner portion of the light guide plate 110A can be increased, and the distance from the corner portion of the frustum of the quadrangular pyramid shape of the second hole portion 20 to the side surface of the light guide plate 110A can be shortened. There are cases where this structure can further suppress uneven brightness depending on the optical characteristics of the light emitting body 100U.

[0094] As the shape of the second hole portion 20 in plan view, in addition to using Figure 2 and Figure 4In addition to the rectangular shape shown, a circular shape may also be adopted. It is not necessary for the second hole portion 20 to have an outer shape similar to the outer shape of the light guide plate 110A in the embodiments of the present disclosure. The shape and size of the second hole portion 20 may be appropriately determined according to the required optical characteristics. For example, the second hole portion 20 may also have a frustum of a cone shape or the like.

[0095] As described above, in Figure 2 In the exemplified structure, the plurality of convex portions 110d are respectively circular in shape. The diameter of the circular shape is, for example, in the range of 1 μm or more and 500 μm or less. Of course, the shape of each convex portion 110d in plan view is not limited to a perfect circular shape. The shape of each of the plurality of convex portions 110d in plan view may also be an oval shape, a deformed circular shape, a polygonal shape, an irregular shape, or the like. It should be noted that in this specification, the shape of the convex portion or the concave portion in plan view refers to the outer edge shape when the convex portion or the concave portion is projected onto a plane parallel to the upper surface of the light guide plate. When the shape of the convex portion (or concave portion) in plan view is other than a circular shape, the diameter of the imaginary circle enclosing the outer edge of the convex portion (or the opening of the concave portion) is, for example, within the above range.

[0096] If the convex portion 110d has a shape protruding from the upper surface 110a of the light guide plate 110D, the effect of increasing the light extracted from the upper surface 110a can be achieved by suppressing total internal reflection inside the light guide plate 110D. Therefore, the convex portion 110d can adopt various shapes such as a hemispherical shape, a conical shape, a pyramidal shape, a frustum of a pyramid, etc.

[0097] In Figure 2 In the shown example, the plurality of convex portions 110d are two-dimensionally arranged in the first region 111A such that the centers are located at the lattice points of a triangular lattice. Of course, the arrangement of the plurality of convex portions 110d is not limited to this example, and any arrangement can be adopted according to the desired optical characteristics. For example, the plurality of convex portions 110d may also be two-dimensionally arranged in the first region 111A such that the centers are located at the lattice points of a square lattice.

[0098] Figure 5 Shows another example of a light guide plate having a plurality of convex portions on the upper surface. In Figure 5 On the upper surface 110a of the shown light-emitting module 100B, there is a light guide plate 110B, which includes a first region 111B and a second region 112B located inside the first region 111B. The second region 112B is an annular region on the upper surface 110a of the light guide plate 110B that surrounds the first hole portion 10A, and the first region 111B is a region located outside the second region 112B and surrounds the second region 112B.

[0099] In Figure 5In the example shown, the first region 111B is a region on the upper surface 110a that is outside the imaginary circle R1, and a plurality of convex portions 110d are provided on its surface. Similar to the example described with reference to Figure 2 , in the first region 111B, the diameter of the circular shape of the convex portion 110d located outside the imaginary circle R2 is larger than the diameter of the circular shape of the convex portion 110d located inside the imaginary circle R2. The region 111Ba in the first region 111B that is outside the imaginary circle R2 may also be referred to as the "outer region", and the region in the first region 111B that is closer to the light-emitting element 120 than the outer region, in other words, the region 111Bb sandwiched between the imaginary circle R1 and the circle R2, may be referred to as the "inner region". In Figure 5 , for ease of understanding, the outer region 111Ba is shown as a region with dark shading, and the inner region 111Bb is shown as a region with light shading.

[0100] On the other hand, the second region 112B is a region on the upper surface 110a that is sandwiched between the imaginary circle R1 and the opening 10a of the first hole portion 10A, and no convex portion 110d is provided on its surface. Therefore, in this example, the surface of the second region 112B is a flat surface. As Figure 5 shown, it is not necessary to form a plurality of convex portions 110d over the entire upper surface 110a. For example, it is sufficient to provide them in at least a part of the first region 111B. By providing a plurality of convex portions 110d, for example, in a region of the light guide plate 110B that is relatively far from the light-emitting element 120, the light extracted from the region relatively far from the light-emitting element 120, that is, the first region 111B, will be larger than that of the second region 112B. As a result, the brightness of the first region 111B located at a position relatively far from the light-emitting element 120 increases, and the occurrence of brightness unevenness can be reduced more effectively.

[0101] In this way, in the examples shown in Figure 2 and Figure 5 , in the upper surface 110a of the light guide plate, the proportion of the plurality of convex portions 110d per unit area increases concentrically with the light-emitting element 120 as the center. Here, the "concentrically" in this specification means having a common center, and it is not necessary to limit the plurality of shapes having a common center to perfect circles. The above-mentioned imaginary circle R1 and / or the circle R2 are not limited to perfect circles and may be ellipses or the like. For example, when the upper surface 110a of the light guide plate 110B is rectangular, the imaginary circle R1 and the circle R2 may also be elliptical. In this case, the center of these ellipses refers to the position where the major axis and the minor axis of the ellipse intersect.

[0102] Figure 6 shows still another example of a light guide plate having a plurality of convex portions on the upper surface. Figure 6The illustrated light-emitting module 100C includes a light guide plate 110C, and a first region 111C is provided on the upper surface 110a of the light guide plate 110C. The first region 111C includes an outer region 111Ca that is more outward than an imaginary circle R2 and an inner region 111Cb that is sandwiched between the imaginary circle R1 and the circle R2.

[0103] In Figure 6 In the illustrated structure, a plurality of convex portions 110d are formed in the first region 111C on the upper surface 110a. In this example, the number density of the plurality of convex portions 110d arranged in the inner region 111Cb in the first region 111C is higher than the number density of the plurality of convex portions 110d arranged in the region that is more inward than the imaginary circle R1 in the first region 111C. In addition, the number density of the plurality of convex portions 110d arranged in the outer region 111Ca is higher than the number density of the plurality of convex portions 110d arranged in the inner region 111Cb. In other words, the number density of the plurality of convex portions 110d arranged in the first region 111C increases as it moves away from the light-emitting element 120.

[0104] Here, the number density of the plurality of convex portions (or concave portions) is defined as the number of convex portions (or concave portions) per unit area on the upper surface of the light guide plate. As Figure 6 shown, by making the number density of the plurality of convex portions 110d increase as it moves away from the light-emitting element 120, the proportion of the convex portions 110d per unit area can be increased concentrically with the light-emitting element 120 as the center. Therefore, with Figure 6 the structure shown, it is also possible to increase the brightness of the region located at a position farther from the light-emitting element 120, and an effect of suppressing brightness unevenness can be obtained.

[0105] In Figure 6 the illustrated example, the farther the plurality of convex portions 110d are from the light-emitting element 120, the denser they are arranged. That is, the plurality of convex portions 110d have an arrangement such that the arrangement pitch decreases as it moves away from the light-emitting element 120. Here, the arrangement pitch of the plurality of convex portions (or concave portions) can be defined for each region (for example, each of the outer region 111Ca and the inner region 111Cb) as the minimum distance between the centers of two adjacent convex portions (or concave portions). The arrangement pitch of the plurality of convex portions 110d can be appropriately selected according to the size and shape of each convex portion 110d and the optical characteristics to be obtained. The arrangement pitch of the plurality of convex portions 110d is, for example, in the range of 10 μm or more and 200 μm or less.

[0106] It should be noted that in this example, a plurality of convex portions 110d are also arranged in the region between the imaginary circle R1 and the opening 10a of the first hole portion 10A. However, the region between the imaginary circle R1 and the opening 10a of the first hole portion 10A can also be set as a second region where no convex portions 110d are arranged.

[0107] [Light-emitting element 120]

[0108] Refer again to Figure 3 . A typical example of the light-emitting element 120 is an LED. In Figure 3 the illustrated structure, the light-emitting element 120 has an element main body 122 and an electrode 124 located on the side opposite to the upper surface 120a of the light-emitting element 120. The element main body 122 includes, for example, a support substrate such as sapphire or gallium nitride and a semiconductor layer stack structure on the support substrate. The semiconductor layer stack structure includes an n-type semiconductor layer, a p-type semiconductor layer, and an active layer sandwiched between the two. The semiconductor layer stack structure may also contain a nitride semiconductor (In x Al y Ga 1-x-y N, 0 ≦ x, 0 ≦ y, x + y ≦ 1) that can emit light in the ultraviolet to visible light range. In this example, the upper surface 120a of the light-emitting element 120 coincides with the upper surface of the element main body 122. The electrode 124 includes a set of a positive electrode and a negative electrode and has a function of supplying a predetermined current to the semiconductor layer stack structure.

[0109] The plurality of light-emitting elements 120 provided in the surface light source 200 may each be an element that emits blue light or an element that emits white light. The plurality of light-emitting elements 120 may also include elements that emit light of different colors. For example, the plurality of light-emitting elements 120 may also include an element that emits red light, an element that emits blue light, and an element that emits green light. Here, as the light-emitting element 120, an LED that emits blue light is illustrated.

[0110] In this example, the light-emitting element 120 in each light-emitting module 100A is fixed to the lower surface side of the wavelength conversion member 150 by the first bonding member 160. The shape of the light-emitting element 120 in plan view is typically a rectangular shape. The length of one side of the rectangular shape of the light-emitting element 120 is, for example, 1000 μm or less. The longitudinal and lateral dimensions of the rectangular shape of the light-emitting element 120 may also be 500 μm or less. Light-emitting elements with longitudinal and lateral dimensions of 500 μm or less are easy to procure at low cost. Alternatively, the longitudinal and lateral dimensions of the rectangular shape of the light-emitting element 120 may also be 200 μm or less. When the length of one side of the rectangular shape of the light-emitting element 120 is small, in applications to the backlight unit of a liquid crystal display device, it is advantageous for the presentation of high-definition video, local dimming operation, etc. In particular, for a light-emitting element in which both the longitudinal and lateral dimensions are 250 μm or less, since the area of the upper surface is small, the amount of light emitted from the side surface of the light-emitting element relatively increases. Therefore, it is easy to obtain a bat-wing type light distribution characteristic. Here, the so-called bat-wing type light distribution characteristic is, in a broad sense, a light distribution characteristic defined by the following light intensity distribution, in which the light intensity is high at an angle where the absolute value of the light distribution angle is greater than 0° when the optical axis perpendicular to the upper surface of the light-emitting element is set to 0°.

[0111] [Wavelength conversion member 150]

[0112] In Figure 3 the illustrated structure, the wavelength conversion member 150 is disposed inside the second hole portion 20 and between the light guide plate 110A and the light-emitting element 120. In other words, the wavelength conversion member 150 is located above the light-emitting element 120 and at the bottom of the second hole portion 20. Here, the so-called "bottom of the second hole portion 20" refers to the portion corresponding to the bottom of the second hole portion 20 when the lower surface 110b of the light guide plate faces upward. Thus, in this specification, regarding the light-emitting module, regardless of the posture shown in the drawings, the terms "bottom" and "bottom surface" are sometimes used. In Figure 3 the example shown, when the light-emitting module 100A is in the Figure 3 posture shown, the bottom of the second hole portion 20 can also be said to be the ceiling portion of a dome-shaped structure formed on the lower surface 110b side of the light guide plate 110A.

[0113] The wavelength conversion member 150 absorbs at least a part of the light emitted from the light-emitting element 120 and emits light having a wavelength different from that of the light from the light-emitting element 120. For example, the wavelength conversion member 150 wavelength-converts a part of the blue light from the light-emitting element 120 and emits yellow light. According to this structure, white light can be obtained by mixing the blue light that has passed through the wavelength conversion member 150 and the yellow light emitted from the wavelength conversion member 150. In Figure 3In the exemplary structure, the light emitted from the light-emitting element 120 is basically introduced into the interior of the light guide plate 110A via the wavelength conversion member 150. Therefore, the mixed light diffuses inside the light guide plate 110A, and white light with suppressed brightness unevenness can be extracted from the upper surface 110a of the light guide plate 110A. Compared with the case where wavelength conversion is performed after the light diffuses inside the light guide plate, the embodiment of the present disclosure is more beneficial for light homogenization.

[0114] Typically, the wavelength conversion member 150 is a member in which phosphor particles are dispersed in a resin. As the resin in which particles such as phosphors are dispersed, silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, urea resin, phenol resin, acrylate resin, polyurethane resin, or fluororesin, or a resin containing two or more of these resins can be used. From the viewpoint of efficiently introducing light into the light guide plate 110A, it is beneficial when the base material of the wavelength conversion member 150 has a lower refractive index than the material of the light guide plate 110A. The wavelength conversion member 150 can also be given a light diffusion function by dispersing a material having a refractive index different from that of the base material in the material of the wavelength conversion member 150. For example, particles such as titanium dioxide and silicon dioxide can be dispersed in the base material of the wavelength conversion member 150.

[0115] As the phosphor, well-known materials can be applied. Examples of phosphors are fluoride-based phosphors such as YAG-based phosphors and KSF-based phosphors, nitride-based phosphors such as CASN, and β-sialon phosphors. The YAG-based phosphor is an example of a wavelength conversion substance that converts blue light into yellow light, the KSF-based phosphor and CASN are examples of wavelength conversion substances that convert blue light into red light, and the β-sialon phosphor is an example of a wavelength conversion substance that converts blue light into green light. The phosphor can also be a quantum dot phosphor.

[0116] The phosphors contained in the wavelength conversion member 150 are not necessarily common in the plurality of light-emitting modules 100 included in the surface light source 200. The phosphors dispersed in the base material of the wavelength conversion member 150 can also be made different between the plurality of light-emitting modules 100. A wavelength conversion member that converts incident blue light into yellow light can also be disposed in a part of the second holes 20 provided in the light guide plate 210 of the surface light source 200, and a wavelength conversion member that converts incident blue light into green light can be disposed in another part of the second holes 20. Moreover, a wavelength conversion member that converts incident blue light into red light can be disposed in the remaining second holes 20.

[0117] [First joining member 160]

[0118] The first joining member 160 is a light-transmissive member that covers at least a part of the side surface of the light-emitting element 120. AsFigure 3 As shown in the schematic diagram, typically, the first bonding member 160 has a layered portion located between the upper surface 120a of the light-emitting element 120 and the wavelength conversion member 150.

[0119] As the material of the first bonding member 160, a resin composition containing a transparent resin material as the base material can be used. The first bonding member 160 has a transmittance of, for example, 60% or more with respect to light having the emission peak wavelength of the light-emitting element 120. From the viewpoint of effectively utilizing light, it is beneficial when the transmittance of the first bonding member 160 at the emission peak wavelength of the light-emitting element 120 is 70% or more, and more beneficial when it is 80% or more.

[0120] Typical examples of the base material of the first bonding member 160 are thermosetting resins such as epoxy resins and silicone resins. As the base material of the first bonding member 160, silicone resins, silicone-modified resins, epoxy resins, phenol resins, polycarbonate resins, acrylate resins, polymethylpentene resins, or polynorbornene resins, or a material containing two or more of these resins can also be used. The first bonding member 160 typically has a refractive index lower than that of the light guide plate 110A. The first bonding member 160 can also have a light diffusion function by, for example, using a material having a dispersion refractive index different from that of the base material.

[0121] As described above, the first bonding member 160 covers at least a part of the side surface of the light-emitting element 120. In addition, in this example, the first bonding member 160 has an outer surface which is an interface with the second light reflection member 170 described later. The light emitted from the side surface of the light-emitting element 120 and incident on the first bonding member 160 is reflected upward of the light-emitting element 120 at the position of the outer surface of the first bonding member 160. The shape of the outer surface of the first bonding member 160 in cross-section is not limited to Figure 3 the straight line shape shown. The shape of the outer surface of the first bonding member 160 in cross-section can also be a polygonal line shape, a curved shape convex in the direction approaching the light-emitting element 120, a curved shape convex in the direction away from the light-emitting element 120, etc.

[0122] [Second Light Reflection Member 170]

[0123] The second light reflection member 170 is a light-reflective member located on the lower surface side (opposite to the light guide plate 110A) of the wavelength conversion member 150. As Figure 3As shown, the second light reflection member 170 covers: the outer surface of the first joining member 160, the portion of the side surface of the light-emitting element 120 that is not covered by the first joining member 160, and the region of the lower surface of the light-emitting element 120 on the side opposite to the upper surface 120a excluding the electrode 124. The second light reflection member 170 covers the side surface of the electrode 124. On the other hand, the lower surface of the electrode 124 is exposed from the lower surface of the second light reflection member 170.

[0124] The second light reflection member 170 is formed of a light-reflective material such as a resin material in which light-reflective fillers are dispersed. Here, in this specification, the so-called "reflectivity" and "light reflectivity" mean that the reflectivity at the peak emission wavelength of the light-emitting element 120 is 60% or more. It is beneficial when the reflectivity of the second light reflection member 170 at the peak emission wavelength of the light-emitting element 120 is 70% or more, and more beneficial when it is 80% or more.

[0125] As the base material of the resin material for forming the second light reflection member 170, silicone resin, phenol resin, epoxy resin, BT resin, polyphthalamide (PPA), etc. can be used. As the light-reflective filler, metal particles, or particles of an inorganic material or an organic material having a higher refractive index than the base material can be used. Examples of the light-reflective filler are particles of titanium dioxide, silicon dioxide, zirconium dioxide, potassium titanate, aluminum oxide, aluminum nitride, boron nitride, mullite, niobium oxide, barium sulfate, or particles of various rare earth oxides such as yttrium oxide and gadolinium oxide. It is beneficial when the second light reflection member 170 is white.

[0126] By covering the region of the lower surface of the light-emitting element 120 excluding the electrode 124 with the second light reflection member 170, light leakage to the side opposite to the upper surface 110a of the light guide plate 110A can be suppressed. In addition, by covering the side surface of the light-emitting element 120 with the second light reflection member 170 as well, the light from the light-emitting element 120 can be concentrated upward and efficiently introduced into the wavelength conversion member 150.

[0127] [Second joining member 190]

[0128] As described above, the light-emitting body 100U is disposed at the bottom of the second hole portion 20 through the second joining member 190. As Figure 3 shown, at least a part of the second joining member 190 is located inside the second hole portion 20. The second joining member 190 may also have a portion located between the bottom of the second hole portion 20 and the wavelength conversion member 150. As Figure 3 shown, the second joining member 190 may have a portion that bulges toward the side opposite to the upper surface 110a of the light guide plate 110A and closer to the lower surface 110b of the light guide plate 110A.

[0129] The second joining member 190, like the first joining member 160, is formed of a resin composition containing a transparent resin material as a base material. The material of the second joining member 190 may be different from or the same as that of the first joining member 160. Typically, the second joining member 190 has a refractive index lower than that of the light guide plate 110A.

[0130] [First light reflection member 140]

[0131] The first light reflection member 140 has light reflectivity and covers at least a part of the lower surface 110b of the light guide plate 110A. Here, the first light reflection member 140 covers not only the lower surface 110b of the light guide plate 110A but also the second joining member 190. By covering the second joining member 190 with the first light reflection member 140 as in this example, light leakage from the second joining member 190 to the lower surface 110b side of the light guide plate 110A can be suppressed, thereby improving the light extraction efficiency.

[0132] As referred to Figure 2 As described above, here, as a result of a part of the first light reflection member 140 including the wall portion 140w, an inclined surface 140s is formed on a part of the upper surface 140a of the first light reflection member 140 facing the lower surface 110b of the light guide plate 110A. As referred to Figure 2 As described above, the inclined surface 140s typically surrounds the light-emitting element 120 along the four sides of the rectangular shape of the upper surface 110a of the light guide plate 110A. The inclined surface 140s can function as a reflection surface for reflecting the incident light to the upper surface 110a of the light guide plate 110A. Therefore, by disposing the first light reflection member 140 having the inclined surface 140s on the lower surface 110b side of the light guide plate 110A, the light directed to the lower surface 110b side of the light guide plate 110A can be reflected upward to the upper surface 110a through the inclined surface 140s, and the light can be extracted more efficiently from the upper surface 110a. In addition, by disposing the inclined surface 140s at the peripheral portion of the light guide plate 110A, it is possible to prevent the brightness of the peripheral portion of the light guide plate 110A from being relatively lower than that of the central portion.

[0133] The shape of the inclined surface 140s in cross section may also be Figure 2 as shown in a curved shape, or may be a linear shape. The shape of the inclined surface 140s in cross section is not limited to these, and may include steps, bends, etc.

[0134] Note that the height of the wall portion 140w surrounding the light-emitting element 120 may also be different between the plurality of light-emitting modules 100 included in a surface light source 200 or within a single light-emitting module 100. For example, the height of the inclined surface 140s located at the outermost periphery of the light guide plate 210 of the surface light source 200 among the plurality of inclined surfaces 140s included in the surface light source 200 may be greater than the height of the inclined surfaces 140s located in other portions of the light guide plate 210.

[0135] As the material of the first light reflection member 140, the same material as that of the second light reflection member 170 described above can be applied. The materials of the second light reflection member 170 and the reflective resin layer 130 may also be the same. By making the materials of the first light reflection member 140 and the second light reflection member 170 the same, it is possible to integrally form a light reflection member that covers substantially the entire lower surface 110b of the light guide plate 110A with a light-reflective material. By forming the first light reflection member 140 on the lower surface 110b side of the light guide plate 110A, effects such as strengthening the light guide plate 110A can also be expected.

[0136] [Wiring layer 180]

[0137] The light-emitting module 100A may further include a wiring layer 180 on the lower surface 140b of the first light reflection member 140. As Figure 3 shown, the wiring layer 180 includes wirings electrically connected to the electrodes 124 of the light-emitting elements 120. In this example, the wiring layer 180 is depicted as being located on the second light reflection member 170, but the wiring layer 180 may include a portion located on the lower surface 140b of the first light reflection member 140.

[0138] Typically, the wiring layer 180 is a single-layer film or a laminated film formed of a metal such as Cu. The wiring layer 180 functions as a terminal for supplying a predetermined current to each light-emitting element 120 by being connected to a power source (not shown) or the like.

[0139] By providing the wiring layer 180 on the lower surface 100b side of the light-emitting module 100A, it is possible to electrically connect the plurality of light-emitting elements 120 in the surface light source 200 to each other through the wiring layer 180. That is, it is possible to drive the light-emitting elements 120 in units of, for example, the surface light source 200. As will be described later, by combining a plurality of surface light sources 200 to construct a larger surface light source, it is possible to perform local dimming operations on the surface light source. By providing the wiring layer 180 on the lower surface 100b side of the light-emitting module 100A, wirings are formed on the surface light source 200 side including a plurality of light-emitting elements 120, and connection to a power source or the like becomes easy. That is, by connecting a power source or the like, surface light emission can be simply obtained. Of course, it is also possible to drive the light-emitting elements 120 in units of one or more light-emitting modules 100A.

[0140] As described above, according to an embodiment of the present disclosure, by providing the light guide plate with the first hole portion 10 as a light diffusion structure, it is possible to suppress an extreme increase in brightness at a position directly above the light emitting element 120 and to diffuse the light from the light emitting element 120 in the plane of the light guide plate. As a result, both a thin form factor and uniform light can be achieved. Further, as described with reference to Figure 3 above, by interposing the wavelength conversion member 150 between the light emitting element 120 and the light guide plate 110A, the mixed light can be diffused in the plane of the light guide plate 110A and then emitted from the upper surface 110a of the light guide plate 110A.

[0141] According to an embodiment of the present disclosure, for example, the thickness of the structure including the first light reflecting member 140, in other words, the distance from the lower surface of the electrode 124 of the light emitting element 120 to the upper surface 110a of the light guide plate 110A can be reduced to, for example, 5 mm or less, 3 mm or less, or 1 mm or less. The distance from the lower surface of the electrode 124 of the light emitting element 120 to the upper surface 110a of the light guide plate 110A can be about 0.7 mm or more and 1.1 mm or less.

[0142] Figure 7 An example showing the connection of the surface light source 200 to the wiring substrate is presented. In one embodiment, as Figure 7 shown, the light emitting device of the present disclosure may include a wiring substrate 260. The wiring substrate 260 is located on the lower surface side of the surface light source 200, that is, on the side opposite to the upper surface 210a of the light guide plate 210, and is connected to the wiring layer 180 of the light emitting module 100.

[0143] In Figure 7 the illustrated structure, the wiring substrate 260 includes: an insulating substrate 265, a wiring layer 262 on the insulating substrate 265, and a plurality of through holes 264 disposed inside the insulating substrate 265. The wiring layer 262 is provided on the main surface of the insulating substrate 265 on the side opposite to the light emitting module 100. The wiring layer 180 of the light emitting module 100 is joined to the through holes 264 of the wiring substrate 260 via a third joining member such as solder provided on the other main surface (the main surface on the light emitting module 100 side) of the insulating substrate 265. The wiring layer 262 is electrically connected to the wiring layer 180 of the light emitting module 100 via the through holes 264.

[0144] According to the present embodiment, since the wiring layer 180 connected to each light-emitting element 120 can be provided on the side of the surface light source 200, it is possible to easily form the required connections such as local dimming without forming a complex wiring pattern on the side of the wiring substrate 260. Since the wiring layer 180 can have an area larger than the lower surface of the electrode 124 of each light-emitting element 120, it is also relatively easy to form an electrical connection to the wiring substrate 260. Alternatively, for example, when the light-emitting module 100 does not have the wiring layer 180, the electrode 124 of the light-emitting element 120 can be connected to the through hole 264 of the wiring substrate 260.

[0145] Figure 8 An example of the wiring pattern of the wiring layer 180 is shown. For simplicity, in Figure 8 an example is shown in which four of the surface light sources 200 shown in Figure 1 are connected to one driver 250.

[0146] As described above, each surface light source 200 can have a wiring layer 180. The wiring layer 180 in each surface light source 200 electrically connects a plurality of light-emitting modules 100 included in the surface light source 200 to each other. In the example shown in Figure 8 , the wiring layer 180 in each surface light source 200 serially connects four light-emitting elements 120, and connects four groups of the serially connected light-emitting elements 120 in parallel.

[0147] As shown in Figure 8 , these wiring layers 180 can be respectively connected to the driver 250 that drives the light-emitting element 120. The driver 250 can also be arranged on a substrate (such as the wiring substrate 260) that supports the set of surface light sources 200 and electrically connected to the wiring layer 180, or can be arranged on a substrate separate from the substrate that supports the set of surface light sources 200 and electrically connected to the wiring layer 180. Based on this circuit structure, it is possible to realize local dimming operation in units of the surface light source 200 including 16 light-emitting elements 120. Of course, the connection of the plurality of light-emitting elements 120 realized by the wiring layer 180 is not limited to the example shown in Figure 8 , and the light-emitting modules 100 in the surface light source 200 can also be connected in such a way that each light-emitting module 100 is independently driven. Alternatively, the light-emitting modules 100 included in the surface light source 200 can be divided into multiple groups, and then the plurality of light-emitting elements 120 can be electrically connected in such a way that the light-emitting elements 120 can be driven in units of groups including multiple light-emitting modules 100.

[0148] Figure 9 An example in which a plurality of surface light sources 200 are two-dimensionally arranged is shown. By two-dimensionally arranging a plurality of surface light sources 200, a large-area light-emitting surface can be obtained.

[0149] Figure 9 The surface light source 300 shown has a plurality of Figure 1 the surface light sources 200 shown. Figure 9 This is an example in which the surface light sources 200 are arranged in 8 rows and 16 columns, and schematically shows the appearance when observing the two-dimensional arrangement of the surface light sources 200 from the upper surface 210a side of the light guide plate 210.

[0150] Typically, the light guide plates 210 of two adjacent surface light sources 200 in the row direction or the column direction are in direct contact with each other. However, it is not necessary to form the two-dimensional arrangement in such a way that the light guide plates 210 of two adjacent surface light sources 200 are in direct contact with each other, and a light guide structure for optically coupling them to each other can also be interposed between the two light guide plates 210 adjacent to each other. Such a light guide structure can be formed, for example, by applying an adhesive that imparts light transmissivity to the side surface of the light guide plate 210 and then curing the applied adhesive. Alternatively, a light guide structure can also be formed by two-dimensionally arranging a plurality of surface light sources 200 with a space therebetween and filling the region between two adjacent light guide plates 210 with a light-transmissive resin material and then curing the resin material. As the material of the light guide structure located between the light guide plates 210, for example, the same material as the above-described first bonding member 160 can be used. It is beneficial to be able to use a material having a refractive index equal to or higher than that of the material of the light guide plate 210 as the base material of the light guide structure. A light diffusion function can also be imparted to the light guide structure located between the light guide plates 210.

[0151] When the longitudinal length L and the lateral length W of each surface light source 200 are, for example, about 24.3 mm and 21.5 mm, respectively, Figure 9 the arrangement of the surface light sources 200 shown is suitable for a 15.6-inch screen size with an aspect ratio of 16:9. For example, Figure 9 the surface light source 300 shown can be applied to the backlight unit of a notebook computer having a 15.6-inch screen size.

[0152] In this example, the set of the upper surfaces of each surface light source 200, that is, the upper surface 210a of the light guide plate 210, constitutes the light emitting surface. Therefore, by changing the number of the surface light sources 200 included in the surface light source 300 or changing the arrangement of the surface light sources 200, the surface light source 300 can be easily applied to a variety of liquid crystal displays with different screen sizes. That is, it is possible to flexibly cope with changes in the screen size without having to re-perform optical calculations related to the light guide plate 210 and the like in the surface light source 200 or re-manufacture the mold for forming the light guide plate 210. Therefore, changes in the screen size do not result in an increase in the manufacturing cost and the development cycle.

[0153] Figure 10Indicates that the Figure 9 Combination of multiple surface light-emitting light sources 200 shown is further arranged in 2 rows and 2 columns. In this case, with a total of 512 surface light-emitting light sources 200, a surface light-emitting light source 400 suitable for a 31.2-inch screen size with an aspect ratio of 16:9 can be formed. Figure 10 The arrangement of the surface light-emitting light sources 200 shown can be used, for example, in the backlight unit of a liquid crystal TV. Thus, according to this embodiment, it is also relatively easy to obtain a larger light-emitting surface.

[0154] According to the method of forming a larger light-emitting surface by combining multiple surface light-emitting light sources 200, it is possible to flexibly cope with liquid crystal displays of various screen sizes without having to re-design the optical system according to the screen size or reproduce the mold for forming the light guide plate. That is, a backlight unit suitable for the screen size can be provided at low cost and with a short delivery period. In addition, even when there are light-emitting elements that are not lit due to open circuits or the like, the advantage is that only the surface light-emitting light source including the defective light-emitting element needs to be replaced.

[0155] Figure 11 Indicates a light-emitting module according to another embodiment of the present disclosure. Compared with the light-emitting module 100A described with reference to Figure 2 etc., Figure 11 the light-emitting module 100D shown has a light guide plate 110D instead of the light guide plate 110A.

[0156] Figure 11 The upper surface 110a of the light guide plate 110D of the light-emitting module 100D shown has a second region 112D that is more inward than the first region 111D and the first region 111D. A plurality of convex portions 110e are provided on the first region 111D of these two regions. In this example, the plurality of convex portions 110e are each formed in the form of a convex ring having an annular shape on the first region 111D of the upper surface 110a. It should be noted that in Figure 11 , for ease of understanding, the plurality of convex portions 110e are presented by shading with hatching. The cross-section of the light guide plate 110D can be substantially the same as the cross-section of the light guide plate 110A shown in the upper section of Figure 2 . Therefore, the illustration of the cross-section of the light-emitting module 100D is omitted here.

[0157] In Figure 11 the exemplified structure, the plurality of convex portions 110e include a first convex ring 110ea and a second convex ring 110eb located more outward than the first convex ring 110ea. The second convex ring 110eb has a width larger than that of the first convex ring 110ea. By like Figure 11As in the example shown, for example, the widths of the plurality of convex rings expand as they move away from the light-emitting element 120, and the proportion of the plurality of convex portions 110e per unit area in a plan view can expand concentrically with the light-emitting element 120 as the center. Therefore, similar to the case where the plurality of convex portions are arranged at multiple points in the first region, the brightness at positions away from the light-emitting element 120 can be increased in the first region, and the effect of suppressing brightness unevenness can be obtained.

[0158] In Figure 11 , the second convex ring 110eb is drawn in a shape obtained by cutting off a part of a circular ring shape, but this is because each convex ring is exaggeratedly enlarged for ease of explanation. As Figure 11 shown by the double-dot chain line, if it is a shape that can be regarded as a circular ring shape considering the part located outside the upper surface 110a of the light guide plate, it can be considered that such a shape is also included in the "circular ring shape" of the present disclosure.

[0159] As the distance from the light-emitting element 120 increases, instead of expanding the width of the convex portion having a circular ring shape, the interval between the plurality of convex portions can be reduced while keeping the width of the convex portion having a circular ring shape constant. According to this structure, the number density of the convex portions contained per unit area can be increased. Therefore, the proportion of the plurality of convex portions 110e per unit area in a plan view can expand concentrically. Alternatively, in addition to expanding the width of the convex portion having a circular ring shape, the interval between the plurality of convex portions can also be reduced.

[0160] A plurality of convex portions each having a circular ring shape and a plurality of convex portions each being dot-shaped can also be mixed and present on the upper surface 110a. By arranging dot-shaped convex portions in addition to the convex portions having a circular ring shape, the occurrence of a light and dark pattern of the circular ring shape can be suppressed compared to the case where only the convex portions having a circular ring shape are arranged.

[0161] Figure 12 is a diagram schematically showing a cross section of a light-emitting module according to still another embodiment of the present disclosure. Compared with the light-emitting module 100A described with reference to Figure 2 and Figure 3 , Figure 12 the light-emitting module 100E shown has a light guide plate 110E instead of the light guide plate 110A. The main difference between the light guide plate 110A and the light guide plate 110E is that a plurality of concave portions 110f are formed in the first region 111E of the upper surface 110a of the light guide plate 110E instead of the plurality of convex portions 110d. As Figure 12 shown in the schematic diagram, these plurality of concave portions 110f have a shape such that, for example, their openings 1a increase as they move away from the light-emitting element 120. It should be noted that in Figure 12 , for ease of explanation, the plurality of concave portions 110f are exaggeratedly enlarged.

[0162] The plurality of recesses 110f provided in the first region 111E may be, for example, a plurality of points. Here, the "point" in this specification generally refers to a structure having a circular shape represented by a circle and an ellipse in a top view, and the "point" in this specification is interpreted to include either a shape protruding from the upper surface 110a of the light guide plate or a shape recessed with respect to the upper surface 110a. In Figure 12 In the illustrated structure, the plurality of recesses 110f are each a structure recessed from the upper surface 110a of the light guide plate toward the lower surface 110b side.

[0163] The plurality of recesses 110f may have a shape obtained by inverting the plurality of convex portions 110d described with reference to Figure 2 , Figure 5 and Figure 6 with respect to the upper surface 110a. The plurality of recesses 110f are each, for example, a dot-shaped recess in which the opening 1a has a circular shape in a top view. In this example, similar to the example shown in Figure 2 , the first region 111E occupies the entire region of the upper surface 110a that does not overlap with the first hole portion 10A, and in the first region 111E, the ratio of the area occupied by the recesses 110f per unit area increases concentrically with the light-emitting element 120 as the center.

[0164] Thus, when the plurality of recesses 110f are arranged in the first region 111E, similar to the case where the plurality of convex portions 110d are arranged, the brightness of the upper surface 110a can be increased according to the ratio of the area occupied by the recesses 110f per unit area. Similar to the example shown in Figure 5 , a second region in which the recesses 110f are not arranged may be provided between the imaginary circle R1 and the opening 10a of the first hole portion 10A. An inner region and an outer region may be provided in the first region 111E, and the diameter of the plurality of recesses 110f located in the outer region may be made larger than the diameter of the plurality of recesses 110f located in the inner region.

[0165] Instead of the size of the recesses 110f increasing as the distance from the light-emitting element 120 increases, or in addition to increasing the size of the recesses 110f, similar to the example shown in Figure 6 , the number density of the recesses 110f may be increased as the distance from the light-emitting element 120 increases. The number density of the plurality of recesses 110f in the outer region may also be made higher than the number density of the plurality of recesses 110f in the inner region. With this structure, the ratio of the area occupied by the recesses 110f per unit area can also be increased concentrically with the light-emitting element 120 as the center. Alternatively, the plurality of recesses 110f may be arranged to be denser as the distance from the light-emitting element 120 increases. For example, the arrangement pitch of the plurality of recesses 110f may be made smaller as the distance from the light-emitting element 120 increases.

[0166] A plurality of recesses 110f may also be formed in a ring-shaped groove portion in the first region of the upper surface 110a. For example, by widening the width of the ring-shaped groove portion as it moves away from the light-emitting element 120, the proportion of the plurality of recesses per unit area in a plan view can be concentrically expanded centering on the light-emitting element 120. Alternatively, the intervals between the plurality of recesses each having a ring shape may be reduced.

[0167] Figure 13 FIG. is a cross-sectional view schematically showing another embodiment of the light-emitting module of the present disclosure. Figure 13 The upper surface 110a of the light guide plate 110F of the shown light-emitting module 100F has a first region 111F. In this example, a plurality of convex portions 110d and a plurality of recesses 110f are arranged in the first region 111F. In this way, the plurality of convex portions and the plurality of recesses can be mixed and arranged in the first region. The first region of the upper surface 110a of the light guide plate may have any combination of two or more selected from a plurality of convex portions each being dot-shaped, a plurality of recesses each being dot-shaped, a plurality of convex portions each having a ring shape, and a plurality of recesses each having a ring shape.

[0168] In this way, a plurality of convex portions and a plurality of recesses can also coexist on the upper surface 110a of the light guide plate. Here, the light guide plate 210 of the surface light source 200 is formed, for example, of a thermoplastic resin such as polycarbonate by a method using a mold such as injection molding. At this time, by previously forming a recess in the cavity of the mold, it is possible to easily form a convex portion having a shape corresponding to the shape of the recess previously formed in the mold on the surface of the light guide plate. Therefore, when comparing the convex portion and the recess, from the viewpoint of the ease of formation, it is advantageous to provide the convex portion on the upper surface 110a of the light guide plate.

[0169] According to the molding method using a mold, by controlling the shape and arrangement of the convex portion protruding inward of the cavity, it is possible to accurately form a recess having a desired shape at a desired position on the upper surface 210a of the light guide plate 210 and at a desired position on the lower surface on the opposite side to the upper surface 210a. Therefore, for example, the first hole portion on the upper surface 210a side and the second hole portion on the lower surface side of the light guide plate 210 can be formed such that their centers are substantially aligned. Instead of providing the second hole portion on the lower surface side of the light guide plate 210, the light-emitting body 100U may be arranged on the lower surface side of the light guide plate 210.

[0170] The shape of the first hole portion 10A is not limited to Figures 2 to 7 , Figures 11 to 13 the illustrated inverted frustum shape, and various shapes such as an inverted pyramid frustum shape, an inverted cone shape without a bottom surface 10b, or an inverted pyramid shape may be adopted. The shape of the side surface 10c in a cross-sectional view may also be a curved shape, a shape including a step or a bend, or the like.

[0171] As Figure 14 shown, the first hole portion 10B including two portions with different inclinations on the side surface can also be applied instead of the first hole portion 10A. Figure 14 The light emitting module 100G shown is an example in which the first hole portion 10B is applied to the upper surface 110a of the light guide plate 110G provided with a plurality of convex portions 110d in the first region 111G.

[0172] The first hole portion 10B includes: a first portion 11A having a first side surface 11c inclined with respect to the upper surface 110a, and a second portion 12A having a second side surface 12c inclined with respect to the upper surface 110a. As shown in the figure, the second side surface 12c of the second portion 12A is a portion located between the opening 12a on the upper surface 110a of the light guide plate 110G and the first side surface 11c of the first portion 11A among one or more side surfaces defining the shape of the first hole portion 10B. The magnitude of the inclination of the first side surface 11c with respect to the upper surface 110a and the magnitude of the inclination of the second side surface 12c with respect to the upper surface 110a are different from each other. In Figure 14 the illustrated structure, the first portion 11A of the first hole portion 10B has a substantially inverted conical shape, and the second portion 12A has an inverted frustum shape.

[0173] In this example, the reflective resin layer 130 is located in the first portion 11A of the first hole portion 10B. The reflective resin layer 130 is formed of, for example, the same material as the material of the first light reflecting member 140 or the second light reflecting member 170 and has light reflectivity. By disposing the reflective resin layer 130 above the light emitting element 120, the light emitted from the light emitting element 120 and traveling toward the upper surface 110a of the light guide plate 110G near the center of the light guide plate 110G can be reflected by the reflective resin layer 130. Therefore, the light emitted from the light emitting element 120 can be efficiently diffused in the plane of the light guide plate 110G. In addition, it is possible to suppress the local extreme increase in the brightness of the region directly above the light emitting element 120 on the upper surface 110a of the light guide plate 110G. However, the reflective resin layer 130 does not necessarily completely block the light from the light emitting element 120. This means that the reflective resin layer 130 can also have a transmissive and reflective property that allows a part of the light from the light emitting element 120 to be transmitted.

[0174] In the embodiment of the present disclosure, the entire first portion 11A of the first hole portion 10B does not necessarily have to be filled with the reflective resin layer 130. The reflective resin layer 130 only needs to occupy a part of the first portion 11A. For example, the reflective resin layer 130 can also be formed in the first hole portion 10B so as to cover the first side surface 11c of the first portion 11A. The reflective resin layer 130 can be omitted.

[0175] Figure 15 This is a cross-sectional view schematically showing another embodiment of the present disclosure's light-emitting module. Figure 15 The illustrated light-emitting module 100H includes: a light guide plate 110H, and a light-emitting body 100T including a light-emitting element 120 and a wavelength conversion member 150A. As Figure 15 shown in the schematic diagram, the light-emitting body 100T is disposed at the bottom of the second hole portion 20 of the light guide plate 110H through a second bonding member 190.

[0176] In this example, the wavelength conversion member 150A covers not only the upper surface 120a of the light-emitting element 120 but also the side surface of the element main body 122. Thus, the shape of the wavelength conversion member is not limited to a plate shape, and may also be a shape that covers the side surface of the light-emitting element 120. Further, in this example, the first light reflection member 140 also covers the portion of the wavelength conversion member 150A and the light-emitting element 120 that is on the side opposite to the upper surface 110a of the light guide plate 110H. However, the lower surface of the electrode 124 of the light-emitting element 120 is exposed from the lower surface 140b of the first light reflection member 140 on the lower surface 100b side of the light-emitting module 100H. According to this structure, light traveling from the light-emitting element 120 toward the lower surface 100b side of the light-emitting module 100H can be prevented from leaking out from the lower surface 140b.

[0177] Industrial Applicability

[0178] Embodiments of the present disclosure are useful for various lighting light sources, vehicle-mounted light sources, display light sources, etc. In particular, it can be advantageously applied to a backlight unit for a liquid crystal display device. The light-emitting module or surface light source of the embodiments of the present disclosure can be applied to a backlight for a display device of a mobile device that strictly requires thickness reduction, a surface light-emitting device capable of performing local dimming control, and the like.

Claims

1. A light-emitting module, comprising: A light guide plate having an upper surface provided with a first hole portion and having a rectangular shape in plan view, and a lower surface opposite to the upper surface; A light-emitting element opposed to the first hole portion and disposed on the lower surface side of the light guide plate, The upper surface of the light guide plate has a first region including a plurality of convex portions or concave portions, In plan view, the proportion of the plurality of convex portions or concave portions per unit area increases concentrically with the light-emitting element as the center, The upper surface of the light guide plate further has a second region surrounding the first hole portion, The first region is located outside the second region, The plurality of convex portions or concave portions are respectively points having a circular shape in plan view, The first region includes: An outer region; and An inner region located closer to the light-emitting element than the outer region; The diameter of the circular shape is larger in the outer region than in the inner region, The inner region is located inside a virtual circle centered on the light-emitting element, The outer region is located outside the virtual circle, The virtual circle includes a portion located outside the outer edge of the light guide plate.

2. The light-emitting module according to claim 1, wherein The second region is a ring surrounding the first hole portion and is composed of a flat surface.

3. The light-emitting module according to claim 1 or 2, wherein The number density of the plurality of convex portions or concave portions increases as it is farther from the light-emitting element.

4. The light-emitting module according to claim 1 or 2, wherein The arrangement pitch of the plurality of convex portions or concave portions decreases as it is farther from the light-emitting element.

5. The light-emitting module according to claim 1 or 2, wherein The lower surface of the light guide plate has a second hole portion at a position opposed to the first hole portion, The light-emitting element is located inside the second hole portion in plan view.

6. The light-emitting module according to claim 5, wherein It further includes a wavelength conversion member located inside the second hole portion and between the light-emitting element and the light guide plate.

7. The light-emitting module according to claim 1 or 2, wherein The light-emitting element has an electrode on the side opposite to the light guide plate, The light-emitting module further includes a light reflection member covering at least a part of the lower surface of the light guide plate.

8. A surface light source, comprising a plurality of light-emitting modules according to any one of claims 1 to 7, wherein The plurality of light-emitting modules are arranged two-dimensionally.

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