TW202115443A - Light emitting module - Google Patents

Abstract

A light emitting module comprising a light guide plate and a light source. The light guide plate has a polygonal shape with a plurality of corners in a plan view. The light guide plate has a first primary face which serves as an emission face, a second primary face opposing the first primary face, and a recessed portion in the second primary face. The light source is disposed in the recessed portion. The recessed portion has an opening on the second primary face, and a bottom face having a polygonal shape in a plan view. The light source has lateral faces along sides of the bottom face of the recessed portion. In a plan view, diagonal lines connecting opposing corners of the first primary face intersect with the sides of the bottom face of the recessed portion.

Description

Light-emitting module

The present invention relates to a light emitting module.

Light-emitting modules using light-emitting elements such as light-emitting diodes are widely used in surface light sources such as backlights of liquid crystal displays. For example, in a direct type liquid crystal display in which a surface light source is arranged on the back of a liquid crystal panel, there is a higher requirement for the thinning of the surface light source. As the surface light source becomes thinner, and the distance between the light source and the light-emitting surface of the light guide plate becomes shorter, the light will not be sufficiently scattered, and uneven brightness or color unevenness is likely to occur on the light-emitting surface. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2018-133304 A

[The problem to be solved by the invention]

The present invention provides a light-emitting module capable of reducing uneven brightness or uneven color in the light-emitting surface of a light guide plate. [Technical means to solve the problem]

According to an aspect of the present invention, the light-emitting module includes a light guide plate and a light source. The light guide plate has a corner shape with a plurality of corners in a plan view, and has: a first main surface that becomes a light-emitting surface, a second main surface opposite to the first main surface, and a second main surface provided on the second main surface The concave part. The light source is arranged in the concave portion. The recess has an opening on the second main surface side and a bottom surface that is angular in plan view. The light source has a side surface along the side of the bottom surface of the concave portion. In a plan view, a diagonal line connecting the plurality of corners of the first main surface intersects the side of the bottom surface of the recess. [Effects of Invention]

According to the present invention, a light-emitting module capable of reducing uneven brightness or uneven color in the light-emitting surface of the light guide plate is provided.

Hereinafter, the embodiment will be described with reference to the drawings. In addition, in each drawing, the same elements are given the same symbols.

FIG. 1 is a schematic top view of the light emitting module 1 of the embodiment. Fig. 2 is a sectional view taken along line A-A of Fig. 1;

The light-emitting module 1 includes a light guide plate 10 and a light source 20. The light source 20 has a light-emitting element 21, a phosphor layer 22, and a covering member 23.

The light guide plate 10 is transparent to the light emitted by the light source 20. As the material of the light guide plate 10, for example, thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, polyester, thermosetting resins such as epoxy and silicone, glass, etc. can be used. Among them, polycarbonate with high transparency and low cost is preferred.

The light guide plate 10 has a first main surface 11 serving as a light-emitting surface, a second main surface 12 opposite to the first main surface 11, and a recess 15 provided on the second main surface 12. Furthermore, the light guide plate 10 has a side surface 13 connected to the first main surface 11 and an inclined surface 14 provided between the side surface 13 and the second main surface 12.

At least the phosphor layer 22 of the light source 20 is configured with the recess 15 of the light guide plate 10. A light-emitting element 21 is provided on the surface of the phosphor layer 22 opposite to the surface on the first main surface 11 side of the light guide plate 10. The concave portion 15 can function as a positioning portion of the light source 20 with respect to the light guide plate 10.

The light emitting element 21 has a main light emitting surface 21b, and a positive and negative pair of electrodes 21a provided on the opposite side of the main light emitting surface 21b. The light emitting element 21 has a semiconductor multilayer structure. The semiconductor multilayer structure may include In _x Al _y Ga _1-xy N (0≦x, 0≦y, x+y≦1), for example, and emit blue light.

The main light-emitting surface 21b of the light-emitting element 21 is bonded to the phosphor layer 22 by, for example, a translucent adhesive. In the example shown in FIGS. 2 and 3, the side surface of the light-emitting element 21 and the electrode 21 a are located outside the recess 15. Or, the light-emitting element 21 may be arranged in the recess 15. A covering member 23 is provided on the side surface of the light-emitting element 21. The covering member 23 is also arranged between the electrodes 21a on the lower surface of the light-emitting element 21. The covering member 23 has reflectivity to the light emitted by the phosphor in the light-emitting element 21 and the phosphor layer 22, and is, for example, a resin containing a white dye. In particular, the covering member 23 is preferably a silicone resin containing titanium oxide.

The phosphor layer 22 has a base material and a phosphor dispersed in the base material. As the material of the base material of the phosphor layer 22, for example, epoxy resin, silicone resin, glass, etc. can be used. From the viewpoint of light resistance and easy formability, a silicone resin is preferable as the base material.

The phosphor is excited by the light emitted by the light emitting element 21, and emits light having a wavelength different from that of the light emitted by the light emitting element 21. For example, as the phosphor, YAG phosphor, LAG phosphor, β-sialon (β-SiAlON) phosphor, CASN phosphor, KSF-based phosphor, quantum dot phosphor, etc. can be used. The phosphor layer 22 may include a plurality of phosphors.

An optical function unit 32 is provided on the first main surface 11 side of the light guide plate 10. The optical function part 32 is provided at a position opposed to the concave part 15 formed on the second main surface 12. Preferably, the optical axis of the light-emitting element 21 and the optical axis of the optical function portion 32 are substantially the same. The shape of the optical function portion 32 is, for example, an inverted cone, an inverted quadrangular pyramid, an inverted hexagonal cone, or an inverted polygonal pyramid, or an inverted truncated cone or an inverted polygonal pyramid.

The optical function part 32 is a transparent resin, glass or air layer with a refractive index lower than that of the light guide plate 10, which can be used as the interface between the light guide plate 10 and the optical function part 32 to refract light, and the light guide plate The lens that diffuses the light functions in the direction of the 10 plane. In addition, for example, it may be that a light-reflective material (for example, a reflective film such as a metal or a white resin) is provided in a recess having an inclined surface.

The recess 15 opens from the second main surface 12 side, and has a bottom surface 17 on the side closer to the first main surface 11 than the second main surface 12. The bottom surface 17 of the recess 15 is provided with a light scattering layer 31 containing a light scattering agent. The light scattering layer 31 is disposed between the bottom surface 17 of the recess 15 and the phosphor layer 22. The light scattering layer 31 scatters a part of the light emitted in the direction directly above the light emitting element 21 and returns to the bottom. As a result, the light emitting surface of the light emitting module 1, that is, the first main surface 11 of the light guide plate 10, the area immediately above the light source 20 can be prevented from becoming too brighter than other areas. The light scattering layer 31 can also be omitted, and the phosphor layer 22 can be directly disposed on the bottom surface 17 of the recess 15.

A light-transmitting part 60 is provided around the light source in the recess 15 (around the phosphor layer 22 and around the light scattering layer 31). The light-transmitting part 60 is a light-transmitting resin part that is transparent to the light emitted by the light source 20. The refractive index of the translucent resin portion is lower than the refractive index of the light guide plate 10. Or, the light-transmitting part 60 may also be a void (air layer).

The light guide plate 10 has an inclined surface 14 that forms an obtuse angle with the second main surface 12 and continues to the second main surface 12. The inclined surface 14 and the second main surface 12 are covered with a light reflective resin portion 40.

The light-reflective resin part 40 is reflective to the light emitted by the light source 20, and is, for example, a resin containing a white dye. In particular, the light reflective resin portion 40 is preferably a silicone resin containing titanium oxide.

The electrode 21 a of the light emitting element 21 is joined to the wiring 52. The light-reflective resin portion 40 has insulating properties and covers the side surface of the electrode 21 a of the light-emitting element 21.

The light reflective resin portion 40 is bonded to the wiring board 50. The wiring board 50 has an insulating base 51, wiring 54 provided on the back surface of the base 51, and via holes 53 penetrating the base 51. The via 53 connects the wire 52 and the wire 54, and the electrode 21 a of the light-emitting element 21 is electrically connected to the wire 54 via the wire 52 and the via 53.

As the base material 51 of the wiring board 50, for example, resin and ceramics can be used. As the wiring 52, 54, and the via hole 53, for example, copper can be used.

In this specification, the term "planar view" refers to a plan view of the first main surface 11 of the light guide plate 10 as shown in FIG. 1. In this plan view, the first main surface 11 has a corner shape having a plurality of corners 11a, for example, a quadrangular shape having four corners 11a.

In a plan view, the bottom surface 17 of the recess 15 is also angular. For example, the bottom surface 17 of the recessed portion 15 has four long side portions 17a and four short side portions 17b in which the long side portion 17a is short. Moreover, the bottom surface 17 has a corner part between the long side part 17a and the short side part 17b.

In a plan view, the phosphor layer 22 has an angular shape. The phosphor layer 22 has, for example, a quadrangular shape in a plan view, and has four side surfaces 22a. The four side surfaces 22a are along the long side portion 17a of the bottom surface 17 of the recess 15. In a plan view, the corner portion of the phosphor layer 22 is located opposite to the short side portion 17b of the bottom surface 17 of the recess 15.

In a plan view, the diagonal line connecting the corner portion 11a of the first main surface 11 at the diagonal position intersects the long side portion 17a of the bottom surface 17 of the recess 15. The phosphor layer 22 is positioned on the bottom surface 17 of the recess 15 in such a way that the side surface 22 a of the phosphor layer 22 is along the long side portion 17 a of the bottom surface 17 of the recess 15.

In a plan view, the quadrangular light source 20 is rotated, for example, 45 degrees with respect to the quadrangular shape of the first main surface 11 of the light guide plate 10. In a plan view, the diagonal line connecting the corner portion 11a of the first main surface 11 and the light source 20 The side surface is the side surface 22a of the phosphor layer 22 (the side of the quadrangular phosphor layer 22) intersecting. In a plan view, the corners of the light source 20 (the corners of the phosphor layer 22) are not located on the diagonal line connecting the corners 11a of the first main surface 11, and are not located opposite to the corners 11a. In a plan view, the corners of the light source 20 (the corners of the phosphor layer 22) are located in an area delineated by a diagonal line connecting the corners 11a of the first main surface 11.

In the phosphor layer 22, the side surface 22a has a wider area than the corner, and the brightness of the light emitted from the side surface 22a of the phosphor layer 22 becomes higher than the brightness of the light emitted in the diagonal direction of the phosphor layer 22 High tendency.

In addition, in the first main surface 11 of the quadrangular shape of the light guide plate 10, the distance between the center portion and the corner portion 11a where the phosphor layer 22 is arranged is longer than the distance between the center portion and the side portion, and light is not easy to move toward the first The tendency of the four corners of the main surface 11 to spread.

According to this embodiment, the phosphor layer 22 is arranged with respect to the light guide plate 10 so that the diagonal line connecting the corner 11a of the first main surface 11 crosses the side surface 22a of the phosphor layer 22 so that the phosphor layer The side surface 22a of 22 and the corner portion 11a of the first main surface 11 are positioned so that the light emitted from the phosphor layer 22 can be easily diffused toward the four corners of the first main surface 11 of the light guide plate 10. It reduces the uneven brightness or color unevenness in the light-emitting surface of the light-emitting module 1, that is, the first main surface 11.

Figure 3 is a B-B cross-sectional view of Figure 1. 4 is a perspective view of the elements (the light scattering layer 31, the phosphor layer 22, and the light transmitting portion 60) in the concave portion 15 of the light guide plate 10 of the light emitting module 1 of the embodiment.

The shape of the opening 16 of the recess 15 is, for example, a quadrangular shape, and the shape of the opening 16 of the recess 15 is different from the shape of the bottom surface 17 of the recess 15.

The recess 15 has an inclined surface 18 inclined at an obtuse angle with respect to the bottom surface 17 of the recess 15. The light-transmitting portion 60 is in contact with the inclined surface 18 of the recess 15 and has an inclined surface 61 facing the inclined surface 18 of the recess 15.

In addition, as shown in FIGS. 2 and 4, the light-transmitting portion 60 has an upper surface 63 in contact with the bottom surface 17 of the recess 15 and a vertical surface 62 perpendicular to the bottom surface 17 of the recess 15. The vertical surface 62 is also connected to the light guide plate 10.

In the light-transmitting portion 60, compared to the case where the surfaces contacting the light guide plate 10 are only the upper surface 63 and the vertical surface 62, by forming the inclined surface 61, the contact area with the light guide plate 10 can be enlarged. That is, the boundary surface between dissimilar materials can be enlarged, and the light emitted from the phosphor layer 22 can be easily captured by the light-transmitting portion 60 into the light guide plate 10.

In the plan view shown in FIG. 1, the inclined surface 61 is located between the corner portion 11a of the first main surface 11 and the side surface 22a of the phosphor layer 22, and is located opposite to the corner portion 11a of the first main surface 11 The location. Therefore, it is easy to diffuse the light emitted from the phosphor layer 22 toward the four corners of the first main surface 11 of the light guide plate 10 through the inclined surface 61 of the light-transmitting portion 60, and the uneven brightness in the first main surface 11 can be reduced. Or uneven color.

FIG. 5 is a schematic diagram of the boundary surface between the light guide plate 10 and the light-transmitting portion 60.

By providing the inclined surface 61 on the light-transmitting portion 60, the difference in refractive index between the light-transmitting portion 60 and the light guide plate 10 is utilized, so that the light emitted from the light source 20 easily travels in the diffusion direction. In this way, the first main surface 11 of the light guide plate 10 can be prevented from becoming too bright in the vicinity of the light source 20 as compared with other areas, and the uneven brightness or color unevenness can be reduced. The same applies to the case where the light-transmitting portion 60 is a void (air layer), and the light emitted from the light source 20 travels in the diffusion direction by using the difference in refractive index with the light guide plate 10.

6A to 6C are schematic cross-sectional views showing the manufacturing method of the light-emitting module 1 according to the embodiment.

First, as shown in FIG. 6A, the light guide plate 10 is prepared. The light guide plate 10 can be formed by, for example, injection molding, transfer injection molding, thermal transfer, and the like. By forming the recess 19 for the optical function part 32 and the recess 15 for the phosphor layer 22 together with a mold, the positioning accuracy of the optical function part 32 and the light-emitting element 21 can be improved.

As shown in FIG. 6B, for example, a translucent resin is supplied to the recess 15 as the translucent portion 60. The light-transmitting resin is supplied to the recessed portion 15 in a liquid state or in a fluid state, for example, by a method such as pouring, printing, spraying, or the like.

After the light-transmitting portion 60 is supplied to the concave portion 15, as shown in FIG. 6C, the light source 20 is arranged in the concave portion 15 together with the light scattering layer 31. The light scattering layer 31 is attached to the bottom surface 17 of the recess 15.

The light-scattering layer 31, the phosphor layer 22, and the light-emitting element 21 are integrated in a state of being bonded to each other, and are supplied to the recess 15. At this time, the quadrangular phosphor layer 22 in plan view is self-aligned and positioned such that its side surface 22a is along the long side portion 17a of the bottom surface 17 of the recess 15. Therefore, the light-emitting element 21 is also positioned in a self-aligned manner with respect to the light guide plate 10. In addition, since the area of the opening 16 of the recess 15 is larger than the area of the bottom surface 17, the light scattering layer 31 and the phosphor layer 22 are easily supplied into the recess 15.

After that, the concave portion 19 on the first main surface 11 side of the light guide plate 10 is provided with the optical function portion 32 shown in FIG. 2, and further, the light reflectivity is provided so as to cover the inclined surface 14 and the second main surface 12 of the light guide plate 10 The resin part 40. The wiring board 50 is attached below the light reflective resin portion 40.

In the light emitting module 1 of the embodiment, since the light emitting element 21 is mounted on the light guide plate 10 instead of the wiring board 50, the distance between the light guide plate 10 and the light emitting element 21 can be shortened, and the light emitting module 1 can be realized Thinning. Such a light emitting module 1 can be used as a backlight source of a liquid crystal display, for example. For example, in a direct type liquid crystal display in which the backlight is arranged on the back of the liquid crystal panel, since the distance between the liquid crystal panel and the light-emitting module 1 is relatively close, the brightness or color of the light-emitting module 1 is easily affected by the brightness of the liquid crystal display. Or the uneven color will affect it. By using the light-emitting module 1 with less unevenness in brightness or color as in the embodiment as the backlight source of the direct type liquid crystal display, the unevenness in the brightness or color of the liquid crystal display can be reduced.

FIG. 7 is a schematic top view of a light emitting module 100 according to another embodiment.

The light-emitting module 100 has a light guide plate 10 and a plurality of units 2 periodically arranged on the light guide plate 10. One unit 2 has the same structure as the aforementioned light-emitting module 1.

That is, a plurality of optical function parts 32 are provided on the first main surface 11 side of one light guide plate 10, and a plurality of recesses 15 are formed on the second main surface 12. The light scattering layer 31, the light source 20, and the light transmitting portion 60 are arranged in the recess 15.

FIG. 7 is a plan view of the first main surface 11 of the light guide plate 10. In this plan view, one unit 2 is formed in, for example, a quadrangular shape having four corners 2a. Each unit 2 is arranged in such a way that the side thereof is along the side of the first main surface 11 of the quadrangular shape of the light guide plate 10. Furthermore, in the plan view, the long side portion 17a of the bottom surface 17 of the recess 15 of each unit 2 and the side surface of the light source (side surface 22a of the phosphor layer 22) face the corner portion 2a of each unit 2. The diagonal line connecting the corner portion 2a of one unit 2 intersects the long side portion 17a of the bottom surface 17 of the concave portion 15 of the unit 2. The diagonal line connecting the corner 2a of one unit 2 intersects the side surface 22a of the phosphor layer 22 of the unit 2.

Therefore, the light emitted from the phosphor layer 22 in each cell 2 easily diffuses toward the four corners of the cell 2. In the entire light-emitting surface of the light-emitting module 100, that is, the first main surface 11, the concentration of brightness in the central portion of each unit 2 is suppressed, which can easily reduce uneven brightness or color unevenness in the light-emitting surface of the light-emitting module 100.

In the foregoing, while referring to specific examples, the embodiments of the present invention have been described. However, the present invention is not limited to these specific examples. Based on the above-mentioned embodiments of the present invention, those skilled in the art can appropriately design changes and implement all the modes as long as they include the gist of the present invention and fall within the scope of the present invention. In addition, within the scope of the present invention, as long as those who are familiar with the technology can think of various variations and modifications, it should be understood that these variations and modifications also fall within the scope of the present invention.

1,100: light-emitting module 2: unit 2a: The corner of the unit 10: Light guide plate 11: The first main surface 11a: The corner of the first main surface 12: The second main surface 13: side 14: Inclined surface 15: recess 16: The opening of the recess 17: The bottom of the recess 17a: Long side 17b: Short side 18: Inclined surface 19: recess 20: light source 21: Light-emitting element 21a: Electrode 21b: Main light-emitting surface 22: Phosphor layer 22a: Side of the phosphor layer 23: Coated component 31: light scattering layer 32: Optical Function Department 40: Light reflective resin part 50: Wiring board 51: Substrate 52, 54: Wiring 53: Via 60: Translucent part 61: Inclined surface of light-transmitting part 62: vertical plane 63: upper surface

Fig. 1 is a schematic top view of the light-emitting module of the embodiment. Fig. 2 is a sectional view taken along line A-A of Fig. 1; Figure 3 is a B-B cross-sectional view of Figure 1. Fig. 4 is a perspective view of the elements in the concave portion of the light guide plate of the light-emitting module of the embodiment. 5 is a schematic diagram of the boundary surface between the light guide plate and the light transmitting portion of the light emitting module of the embodiment. 6A is a schematic cross-sectional view showing the manufacturing method of the light-emitting module of the embodiment. 6B is a schematic cross-sectional view showing the manufacturing method of the light emitting module according to the embodiment. 6C is a schematic cross-sectional view showing the manufacturing method of the light-emitting module according to the embodiment. Fig. 7 is a schematic top view of a light-emitting module according to another embodiment.

1: Light-emitting module

10: Light guide plate

11: The first main surface

11a: The corner of the first main surface

15: recess

16: The opening of the recess

17: The bottom of the recess

17a: Long side

17b: Short side

22: Phosphor layer

22a: Side of the phosphor layer

32: Optical Function Department

61: Inclined surface of light transmitting part

Claims (10)

A light-emitting module, which has: The light guide plate has an angular shape with a plurality of corners in a plan view, and has: a first main surface that becomes a light-emitting surface, a second main surface opposite to the first main surface, and a second main surface provided on the second main surface The concave part of the face; and A light source, which is arranged in the aforementioned recess; and The recess has an opening on the second main surface side and a bottom surface that is angular in plan view; The light source has a side surface along the side of the bottom surface of the recess; In a plan view, a diagonal line connecting the plurality of corners of the first main surface intersects the side of the bottom surface of the recess. The light-emitting module of claim 1, wherein, in a plan view, a diagonal line connecting the plurality of corners of the first main surface intersects the side surface of the light source. The light-emitting module of claim 1, wherein a plurality of units each including the aforementioned concave portion and the aforementioned light source and having a quadrangular shape in a plan view are periodically arranged on one of the aforementioned light guide plates; and In a plan view, the sides of the bottom surface of the concave portion of each unit and the side surface of the light source face the corners of each unit. The light-emitting module of claim 1, wherein the concave portion has an inclined surface that forms an obtuse angle with the bottom surface and is inclined. Such as the light-emitting module of claim 4, which is further provided with a light-transmitting portion arranged around the light source in the concave portion, and the light-transmitting portion is in contact with the inclined surface. The light-emitting module of claim 5, wherein the light-transmitting part is a light-transmitting resin part. The light emitting module of claim 6, wherein the refractive index of the translucent resin portion is lower than the refractive index of the light guide plate. The light emitting module of claim 1, wherein the area of the opening of the recess is larger than the area of the bottom surface of the recess. Such as the light-emitting module of claim 1, which further has an optical function part, which is arranged on the first main surface of the light guide plate at a position opposite to the concave part, and has a refractive index greater than that of the light guide plate. Low refractive index. The light-emitting module of claim 1, wherein the light source includes a light-emitting element and a phosphor layer bonded to the main light-emitting surface of the light-emitting element.

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