JP7116320B2 - light emitting device - Google Patents

Description

The present invention relates to a light-emitting device using a light-emitting element.

2. Description of the Related Art Light-emitting devices using light-emitting elements such as light-emitting diodes (LEDs) are widely used as various light sources such as backlights for liquid crystal displays, displays, and illumination. In response to this, for example, semiconductor light emitting devices as disclosed in Patent Documents 1 and 2 have been proposed. In order to obtain planar light emission in such a semiconductor light emitting device, a configuration is known in which a plurality of LEDs are arranged in a matrix on the back side of the light guide plate. In such an arrangement, thinning of the light emitting device is required.

JP 2013-115088 A JP 2014-45194 A

An object of the present invention is to provide a thin light-emitting device with wide light distribution.

A light-emitting device according to one embodiment of the present invention includes a light-emitting element having a top surface, a bottom surface having a pair of electrodes, and side surfaces, and covering the side surfaces to convert the wavelength of light emitted by the light-emitting element to produce light of different wavelengths. a wavelength converting member that emits light; a translucent member that covers an outer surface of the wavelength converting member; a light shielding layer that covers the upper surface of the light emitting element, the upper surface of the wavelength converting member, and the upper surface of the translucent member; A light reflective layer covering the lower surface of the light emitting element and the lower surface of the wavelength converting member is provided.

According to the light emitting device according to one aspect of the present invention, it is possible to obtain a light emitting device that suppresses light from the top surface, increases light from the side surfaces, suppresses color unevenness and brightness unevenness, and approaches uniform surface light emission. becomes possible.

1 is a schematic cross-sectional view showing a light emitting device according to Embodiment 1. FIG. FIG. 2 is a horizontal sectional view along line II-II of FIG. 1; FIG. 11 is a horizontal cross-sectional view of a light emitting device according to Embodiment 4; FIG. 11 is a horizontal cross-sectional view of a light emitting device according to Embodiment 5; FIG. 11 is a horizontal cross-sectional view of a light emitting device according to Embodiment 6; 1 is a schematic plan view showing a planar light emitter using the light emitting device according to Embodiment 1. FIG. FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; FIG. 4 is a schematic cross-sectional view showing one state of the manufacturing process of the light-emitting device according to Embodiment 1; It is a schematic cross section showing a light emitting device according to a comparative example. 5 is a graph showing orientation characteristics of light emitting devices according to Example 1 and Comparative Example 1. FIG.

The present invention will now be described in detail with reference to the drawings. In the following description, terms indicating specific directions and positions (e.g., "upper", "lower", and other terms including those terms) are used as necessary, but the use of these terms is These terms are used to facilitate understanding of the invention with reference to the drawings, and the technical scope of the invention is not limited by the meaning of these terms. Also, parts with the same reference numerals appearing in a plurality of drawings indicate the same or equivalent parts or members.

Furthermore, the embodiments shown below are examples for embodying the technical idea of the present invention, and the present invention is not limited to the following. In addition, unless there is a specific description, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention, but are intended to be examples. It is intended. In addition, the contents described in one embodiment and example can also be applied to other embodiments and examples. Also, the sizes and positional relationships of members shown in the drawings may be exaggerated for clarity of explanation.
[Embodiment 1]

A light-emitting device according to Embodiment 1 of the present invention is shown in the schematic cross-sectional view of FIG. 1 and the horizontal cross-sectional view of FIG. The light emitting device 100 shown in these figures includes a light emitting element 10, a wavelength conversion member 20, a translucent member 30, a light shielding layer 40, and a light reflecting layer 50. FIG.
(Light emitting element 10)

A semiconductor light-emitting element such as a light-emitting diode can be suitably used as the light-emitting element 10 . The light emitting element 10 also has an upper surface, a lower surface having a pair of electrodes 12, and side surfaces. Hereinafter, the upper surface of the light-emitting element 10 is also referred to as the element main surface, the side surface as the element side surface, and the lower surface as the element electrode forming surface.

An element that emits light of any wavelength can be selected as the light emitting element 10 . For example, as a device for emitting blue and green light, a light-emitting device using a nitride semiconductor ( _{InxAlyGa1 -xyN ,} 0≤X, 0≤Y, X+Y≤1) or GaP is used. be able to. A light-emitting element containing a semiconductor such as AlGaAs or AlInGaP can be used as the element that emits red light. Furthermore, semiconductor light-emitting elements made of materials other than these can also be used. The emission wavelength can be varied by changing the material of the semiconductor layer and its degree of alloying. The composition, emission color, size, number, and the like of the light-emitting elements to be used can be appropriately selected according to the purpose. Although only one light-emitting element 10 is used in the example of FIG. 1, two or more light-emitting elements may be included in the light-emitting device.

Further, the light emitting device 10 may be provided with a light reflecting layer between the semiconductor layer and the growth substrate to adjust the brightness and light distribution of the light emitting device. A DBR (Distributed Bragg Reflector) formed as part of an n-type semiconductor, for example, can be used as the light reflecting layer provided in the light emitting element. A DBR is a diffraction grating with a spatial period of λ/2n (where λ is the wavelength of light in vacuum and n is the refractive index in the medium (specifically, the n-type semiconductor layer)).
(Wavelength conversion member 20)

The wavelength conversion member 20 is arranged around the light emitting element 10 so as to cover the side surface of the light emitting element 10 . This wavelength conversion member 20 converts the wavelength of the light emitted by the light emitting element 10 to emit light of a different wavelength. Here, the wavelength conversion member 20 receives light emitted from the side surface of the element, converts the wavelength of the light, and emits the light from the side surface toward the translucent member 30 side.

The wavelength converting member 20 includes a wavelength converting substance that emits light of different wavelengths when excited by the light from the light emitting element 10 . In this way, of the light emitted by the light emitting element 10, the component transmitted through the wavelength conversion member 20 and the component wavelength-converted by the wavelength conversion member 20 are mixed, and mixed color light is emitted.

By continuously covering the light emitting element 10 with the wavelength converting member 20 so as to surround the periphery of the light emitting element 10 in this way, the light emitted from the light emitting element 10 is wavelength-converted by the wavelength converting member 20 over a wide area, and the original light emitted by the light emitting element is changed. can be efficiently mixed. In particular, as shown in FIG. 1, the light shielding layer 40 is brought into contact with the upper surface of the light emitting element 10 to reduce the height of the entire light emitting device 100, thereby realizing a slimmer structure and allowing more light to be emitted from the side surface. With this structure, color unevenness and brightness unevenness can be reduced.

The wavelength converting member 20 can be made by dispersing a wavelength converting substance in a first resin serving as a base material. Moreover, the wavelength conversion member 20 may be composed of a plurality of layers.

As a material constituting the first resin serving as the base material, for example, a phenyl resin, an epoxy resin, a silicone resin, a mixed resin of these, or a translucent material such as glass can be used. Among them, it is preferable to use a phenyl-based resin, which has high hardness after curing and is excellent in workability. From the viewpoint of light resistance and moldability of the wavelength conversion member 20, it is beneficial to select a silicone resin as the first resin. Further, the first resin is preferably a material having a higher refractive index than the material forming the light guide plate 70 described later. This provides an advantage of easy processing by grinding or the like.

A phosphor can be suitably used as the wavelength conversion substance contained in the wavelength conversion member 20 . Examples thereof include YAG phosphors, β-SiAlON phosphors, KSF phosphors, MGF phosphors, and other fluoride phosphors, nitride phosphors, and the like. Specific examples of the compositional formula include the following general formulas (I), (II), and (III).

A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(However, in the above general formula (I), A is at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ⁴⁺ , and M is Group 4 is at least one element selected from the group consisting of elements and Group 14 elements, and a satisfies 0<a<0.2.)

(xa)MgO.a(Ma) _O.b / ₂ (Mb)2O3.yMgF2.c(Mc)X2.( _{1 -} de) _GeO2.d (Md) _O2 . e(Me) _2O3 :Mn ₍ II)
(wherein, in the above general formula (II), Ma is at least one selected from Ca, Sr, Ba and Zn; Mb is at least one selected from Sc, La and Lu; Mc is at least one selected from Ca, Sr, Ba and Zn, X is at least one selected from F and Cl, and Md is at least one selected from Ti, Sn and Zr. and Me is at least one selected from B, Al, Ga, and In, and x, y, a, b, c, d, and e satisfy 2≤x≤4, 0<y≤ 2, 0≤a≤1.5, 0≤b<1, 0≤c≤2, 0≤d≤0.5, 0≤e<1)

_{MaxMbyAl3Nz :} Eu ( _III )
(However, in the general formula (III), Ma is at least one element selected from the group consisting of Ca, Sr and Ba, and Mb is at least one selected from the group consisting of Li, Na and K. x, y and z satisfy 0.5≦x≦1.5, 0.5≦y≦1.2 and 3.5≦z≦4.5, respectively.

The half width of the KSF phosphor represented by formula (I) can be 10 nm or less. Further, the half-value width of the MGF phosphor represented by general formula (II) can be 15 nm or more and 35 nm or less. As shown in the above general formula (I), part of Si constituting the composition K ₂ SiF ₆ :Mn ⁴⁺ of the KSF phosphor is replaced with another tetravalent element Ti or Si (composition formula K ₂ (Si, Ti, Ge) F ₆ :Mn) or a part of K constituting the composition K ₂ SiF ₆ :Mn ⁴⁺ of the KSF phosphor is replaced with another alkali metal. Substitution may be performed, part of Si may be substituted with a trivalent element such as Al, or substitution with a plurality of elements may be combined.

The wavelength conversion member 20 may contain one wavelength conversion substance, or may contain a plurality of wavelength conversion substances. When a plurality of wavelength conversion substances are contained, for example, the wavelength conversion member may contain a β-sialon phosphor that emits greenish light and a fluoride-based phosphor such as a KSF-based phosphor that emits reddish light. can. Thereby, the color reproduction range of the light emitting device can be widened. In this case, the light emitting element 10 is a nitride semiconductor (In _x Aly Ga _{1-xy N} , 0≦X, 0≦Y, X+Y ≤1). Further, for example, when using a light-emitting element that emits blue light, if red light is to be obtained from the light emitting device, KSF phosphor (red phosphor) is added to the wavelength conversion member in an amount of 60% by weight or more. , preferably 90% by weight or more. In other words, the wavelength conversion member may contain a wavelength conversion substance that emits light of a specific color, thereby emitting light of a specific color. Also, the wavelength conversion material may be a quantum dot. The wavelength converting material may be arranged in any manner within the wavelength converting member. For example, they may be distributed substantially uniformly or may be unevenly distributed. Moreover, a plurality of layers each containing a wavelength conversion member may be laminated and provided. Further, the wavelength conversion member may be added with a member that diffuses and reflects light. For example, a light diffusion member may be mixed inside the wavelength conversion member.

The thickness of the wavelength conversion member 20 is preferably 0.02 mm to 0.40 mm. It is preferable to set the thickness within the above range in order to achieve thinning of the light-emitting module and effects of various wavelength conversions.
(translucent member 30)

An outer surface of the wavelength conversion member 20 is covered with a translucent member 30 . The translucent member 30 transmits the light emitted by the light emitting element 10 and the light wavelength-converted by the wavelength conversion member 20 .

The translucent member 30 opens the upper surface of the light emitting element 10 . In other words, it is preferable not to place the translucent member 30 on the upper surface of the light emitting element 10 . As a result, the situation in which high-intensity light is emitted from the upper surface of the light-emitting element 10 through the light-transmitting member 30 is suppressed, and the light from the side surface of the light-emitting element 10 is transmitted through the light-transmitting member 30, thereby reducing the amount of light. In addition, it is possible to suppress color unevenness and luminance unevenness and bring the surface emission closer to uniform surface emission. Preferably, as shown in FIG. 2, the translucent member 30 is configured in a frame shape surrounding the light emitting element 10 with a space therebetween. In the example of the horizontal cross-sectional view of FIG. 2 , the translucent member 30 covers the entire outer circumference of the wavelength conversion member 20 formed in a rectangular shape in plan view. The translucent member 30 serves as a light-emitting region for emitting light from the light-emitting device 100 to the outside.
(Light diffusion material)

Further, the translucent member 30 may contain a light diffusing material. As a result, the light emitted by the light emitting element 10 and the light wavelength-converted by the wavelength conversion member 20 are diffused by the light diffusing material, and the color mixing effect can be enhanced. The translucent member 30 further diffuses the light emitted by the light emitting element 10 and the light wavelength-converted by the wavelength conversion member 20 to promote color mixing. By providing such a translucent member 30, the light emitted from the light emitting device 100 can be made more uniform. It is preferable that the light-transmitting member 30 has a light-transmitting member transmittance of 50% or more. Also, a plurality of translucent members are laminated in the outer peripheral direction to form a light diffusion region.

This translucent member 30 can be configured by adding a diffusion material to a base material. For example, the translucent member 30 can be formed by using a second resin as a base material and containing white inorganic fine particles such as SiO ₂ or TiO ₂ as a diffusing material. Phenyl-based resin, epoxy resin, silicone resin, a resin mixture thereof, or a translucent material such as glass can be used as the resin material of the second resin serving as the base material. Preferably, a phenyl-based resin having high hardness after curing and excellent workability is used. By using the same resin as the wavelength conversion member 20 for the base material of the light-transmitting member 30, excellent adhesiveness is achieved, and the bonding interface between the wavelength conversion member 20 and the light diffusion is not affected by shrinkage of the resin during curing and deformation during expansion. It is possible to suppress the occurrence of stress in the substrate and cause peeling.

As the diffusing material, a white resin or metal, which is a light reflecting member, processed into fine particles can also be used. These diffusing materials are irregularly contained inside the base material, so that the light passing through the translucent member 30 is irregularly and repeatedly reflected to diffuse the transmitted light in multiple directions. This suppresses the local concentration of the irradiation light and prevents the occurrence of luminance unevenness.

In addition, the light-transmissive member 30 and the light-shielding layer 40, which will be described later, are arranged so as to cover the wavelength conversion member 20, thereby protecting the wavelength conversion member 20 from moisture and the like. Therefore, the light-emitting device 100 can be easily manufactured even when using a phosphor that may be adversely affected by moisture from the outside.
(Light shielding layer 40)

The light shielding layer 40 is a member that covers the top surface of the light emitting element 10 , the top surface of the wavelength conversion member 20 , and the top surface of the translucent member 30 . The light shielding layer 40 is a member having a light shielding property. By covering the top surface of the light emitting device 100 with the light shielding layer 40, the brightness of the light from the light emitting element 10 and the wavelength conversion member 20 on the top surface of the light emitting element 10 is increased. suppress The light shielding layer 40 preferably has a light transmittance of 50% or less. Thus, the light shielding layer 40 is not necessarily required to have a perfect light shielding property, and it is sufficient if the light shielding property is incomplete. In this specification, "light-shielding property" does not mean 0% transmittance.

The light shielding layer 40 can be composed of a layer containing a light reflecting resin or a layer containing metal. For example, the light shielding layer 40 is made of resin containing TiO ₂ , SiO ₂ , Al ₂ O ₃ or glass filler. In the example of FIG. 1, the light shielding layer 40 is configured by dispersing a light reflective material in a third resin serving as a base material. For example, the concentration of filler contained in the base material can be about 20-70%. Phenyl-based resin, dimethyl-based resin, epoxy resin, silicone resin, mixed resin of these, or translucent material such as glass can be used as the resin material of the third resin that is the base material. Phenyl-based resins are preferably used. As a result, effects such as high hardness after curing of the resin and easy processing can be obtained. In particular, by using the same resin as the wavelength conversion member 20 and the translucent member 30 for the base material of the light shielding layer 40, the adhesion is excellent, and stress is generated at the joint interface due to shrinkage of the resin during curing and deformation during expansion. Therefore, it is possible to suppress the occurrence of peeling. Further, when a dimethyl-based resin is used for the light-shielding layer 40, if the wavelength conversion member 20 and the translucent member 30 are phenyl-based resins, the light-shielding layer 40 can be formed by providing a refractive index difference at the interface with these. can be reduced. TiO ₂ , SiO ₂ , Al ₂ O ₃ , glass filler, or the like can be used as the light-reflecting material. The refractive index can be selected by using a glass filler. Here, the transmittance can be adjusted by adjusting the content of the filler. It is preferable that the translucent member 30 has a transmittance of 50% or more and the light shielding layer 40 has a transmittance of 50% or less. The translucent member 30 may be laminated. For example, the translucent member 30 is first formed only on the top surface of the light emitting element 10, and is provided so as to cover the top surface of the wavelength conversion member 20, and the top surface of the translucent member 30. good too. In the case of lamination, by adjusting the content and formation range of the filler, it is possible to suppress the brightness in the direction directly above the light emitting element and to reduce color unevenness.

By adopting such a configuration, the light-emitting device 100 described above can suppress luminance unevenness and achieve light emission with a wide light distribution. That is, the light with the highest brightness emitted from the light emitting surface of the upper surface of the light emitting element 10 is blocked by the light shielding layer 40, and the light is emitted from the side surface direction through the diffusion layer. can be optically coupled to obtain uniform emission.

Also, the light shielding layer 40 can be formed as a thick film. For example, the light shielding layer 40 made of white resin is formed with a thickness of about 50 μm to 500 μm. Thus, by increasing the film thickness, it is possible to enhance the light shielding effect.
(Light reflective layer 50)

The light reflective layer 50 is a member that covers the lower surface of the light emitting element 10 and the lower surface of the wavelength conversion member 20 . However, the electrodes of the light emitting element 10 are exposed outside from the light reflective layer 50 . Moreover, the light-reflective layer 50 preferably covers the lower surface of the translucent member 30 as well. In the example of FIG. 1 , the light reflective layer 50 is arranged below the light emitting element 10 , below the wavelength converting member 20 , and below the translucent member 30 . The light-reflecting layer 50 reflects the light emitted by the light-emitting element 10 and the light wavelength-converted by the wavelength conversion member 20 to prevent light from leaking from the bottom surface of the light-emitting device 100 .

The light reflective layer 50 is also formed by dispersing a light reflective material in the fourth resin, which is the base material, similarly to the light shielding layer 40 . Phenyl-based resin, epoxy resin, silicone resin, mixed resin of these, or translucent material such as glass can be used as the resin material of the fourth resin that is the base material. Phenyl-based resins are preferably used. As a result, effects such as high hardness after curing of the resin and easy processing can be obtained. In particular, by using the same resin as the wavelength conversion member 20 and the translucent member 30 for the base material of the light reflective layer 50, the adhesiveness is excellent, and stress is applied to the bonding interface due to shrinkage of the resin during curing and deformation during expansion. can be suppressed from occurring and causing peeling. TiO ₂ , SiO ₂ , Al ₂ O ₃ , glass filler, etc. can be used as the light reflecting material.
(Metal film 60)

The end face of the electrode 12 of the light emitting element 10 exposed from the light reflective layer 50 is covered with the metal film 60 . This metal film 60 functions as an external electrode of the light emitting device 100 . By making the metal film 60 larger than the end face of the electrode 12 of the light emitting element 10, the light emitting device 100 can be easily electrically connected to the outside. Power can be supplied to the light emitting element 10 by using the metal film 60 to mount the light emitting device 100 on a mounting substrate or to electrically connect it to an external wiring by wire bonding. The metal film 60 can be formed of a single-layer film or a laminated film of metals such as Au, Pt, Pd, Rh, Ni, W, Mo, Cr, and Ti, or alloys thereof. Specifically, Ti/Rh/Au, W/Pt/Au, Rh/Pt/Au, W/Pt/Au, Ni/Pt/Au, Ti/Rh and the like are laminated from the light emitting element 10 side. Laminated films are available. In particular, by protecting Cu, which is easily oxidized, with a stable metal such as Au, the reliability of electrical connection can be enhanced.

With such a configuration, it is possible to obtain the light-emitting device 100 that suppresses light from the top surface, increases light from the side surfaces, suppresses color unevenness and luminance unevenness, and approximates uniform surface emission. In other words, in the conventional light emitting device, there is a problem that the brightness in the direction directly above the LED is high, resulting in color unevenness. On the other hand, by providing the light shielding layer 40 on the upper surface of the light emitting element 10, the luminance on this surface is suppressed, and the light emitting device 100 with less color unevenness and wide light distribution can be obtained.
[Embodiments 2 and 3]

In the above examples, the outer shape of the light emitting device is rectangular in plan view. In the example shown in FIG. 2, the rectangular shape is horizontally long, but it may be square like the light emitting device 400 according to the second embodiment shown in FIG. Further, the shape is not limited to a rectangular shape, and may be a polygonal shape such as a hexagonal shape with some corners cut off like the light emitting device 500 according to Embodiment 3 shown in FIG. 4 or an octagonal shape with four corners cut off. or circular.
[Embodiment 4]

Further, in the above example, the configuration in which the entire circumference of the wavelength conversion member 20 is covered with the translucent member 30 in a plan view is shown, but the present invention is not limited to this configuration, and a part of the periphery of the wavelength conversion member is covered with the translucent member. It may also be configured to cover with an elastic member and cover other surrounding portions with another member. For example, like a light-emitting device 600 according to Embodiment 4 shown in FIG. The other (the upper and lower sides of the wavelength conversion member 20 in FIG. 5) may be covered with the second light shielding layer 42 . In this configuration, of the side surfaces of the light-emitting device 600, the portion covered with the translucent member 30 is used as a light-emitting region, and the surface covered with the second light shielding layer 42 is used as a non-light-emitting region. Light emission can be regulated. Further, by concentrating the light-emitting regions, it is possible to obtain an improvement in brightness. Furthermore, the upper and lower sides of the light emitting element 10 are shielded from light, and out of the four lateral surfaces, emitted light is obtained mainly in the left and right directions, thereby imparting anisotropy to the light, making it suitable for applications where luminance is required only in the left and right directions. becomes.
(Light guide plate 70)

The light emitting device according to Embodiments 1 to 4 as described above can be used as a light source for planar light emission, such as illumination or a backlight for liquid crystals. As an example, FIG. 6 shows an example in which the light emitting device is applied to a planar light emitter. In this example, a plurality of light emitting devices 100 are arranged on the back surface of the light guide plate 70 so as to be separated from each other. Each light emitting device 100 is optically connected to the light guide plate 70 . By arranging such a light-emitting device, it becomes possible to reduce the thickness of the planar light-emitting body.

It is preferable to form the light guide plate 70 in a rectangular shape such as a rectangle or a square. Materials for the light guide plate 70 include thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, and polyester; resin materials such as thermosetting resins such as epoxy and silicone; and optically transparent materials such as glass. materials can be used. In particular, a thermoplastic resin material is preferable because it can be efficiently manufactured by injection molding. Among them, polycarbonate, which has high transparency and is inexpensive, is preferable. Moreover, the light guide plate 70 may be formed of a single layer, or may be formed by laminating a plurality of translucent layers. When a plurality of translucent layers are laminated, it is preferable to provide a layer having a different refractive index, such as an air layer, between arbitrary layers. As a result, the light can be diffused more easily, and a planar light emitter with reduced luminance unevenness can be obtained.
(Method for manufacturing light-emitting device)

Next, a method for manufacturing the light emitting device according to Embodiment 1 will be described with reference to schematic cross-sectional views of FIGS. 7 to 20. FIG. First, as shown in FIG. 7, a light reflective layer 50 is prepared. Here, the fourth resin 52 in which the light reflecting material is dispersed is formed on the base sheet 80 . A member having heat resistance can be suitably used for the base sheet 80, for example, a heat-resistant tape having an adhesive layer can be used. A white resin is applied on the base sheet 80 as the fourth resin 52 in which the light reflecting material is dispersed. The white resin has TiO ₂ dispersed in a phenyl resin. Here, a heat-resistant tape having an adhesive layer is adhered and held on the ring RG, but a support plate or the like can be appropriately used as long as the base sheet can be held.

Next, as shown in FIG. 8, the light emitting element 10 is mounted on the uncured white resin. Here, a plurality of light emitting elements 10 are arranged on the upper surface of the white resin while being spaced apart from each other. The light-emitting device 10 is a light-emitting diode in which a GaN-based semiconductor layer is grown on a sapphire substrate. The light-emitting diode has a pair of electrodes 12 projecting from the device electrode forming surface. This element electrode formation surface is pressed so that the electrodes 12 penetrate through the white resin. The white resin is cured in this state to form the light reflective layer 50 .

Next, as shown in FIG. 9, the upper surface of the light reflective layer 50 on which the light emitting element 10 is mounted is covered with the wavelength converting member 20. Next, as shown in FIG. Here, a phenyl-based resin, which is the first resin 22 in which a YAG phosphor is dispersed as a wavelength conversion material, is compression-molded so as to cover the periphery and upper surface of the light-reflective layer 50 . In this state, the first resin 22 is cured to form the wavelength conversion member 20 .

Further, if necessary, the upper surface of the formed body including the cured wavelength conversion member 20 is ground to form a predetermined thickness. In the example shown in FIG. 10, the upper surface of the cured wavelength conversion member 20 is mechanically ground with a grinder or the like. In addition, when the thickness can be controlled by adjusting the amount of the first resin 22 at the time of forming the wavelength conversion member 20, the mechanical grinding process can be omitted.

Further, in the example shown in FIG. 10 , the molded body is transferred from the base sheet 80 to the UV tape 90 . The UV tape 90 is an adhesive tape having a property of weakening the adhesive force by irradiation with UV light (ultraviolet rays) while having sufficient adhesive force. By using the UV tape 90, the wafer is securely fixed with a strong adhesive force during the grinding or cutting of the wavelength conversion member 20, and after the processing is completed, the UV light is irradiated to weaken the adhesive force, thereby preventing the tape from peeling off. Facilitates die pick-up. This makes it possible to improve the quality and reduce the cost of manufacturing semiconductor devices.

Further, as shown in FIG. 11, the light emitting device is separated into individual pieces. Here, a dicer or the like is used to cut out the wavelength conversion layer for each light emitting element 10 . Each singulated wavelength conversion layer is placed on the second base sheet 82 . For example, similarly to FIG. 7, as shown in FIG. 12, a new light reflective layer 50 is prepared on the second base sheet 82, and the individual pieces are separated and rearranged. Before FIG. 12, the same process as in FIG. 7 is performed to prepare the light reflecting layer 50 again and rearrange the cut light emitting elements.

Further, a translucent member 30 is formed. For example, as shown in FIG. 13, the second resin 32 in which the light diffusing material is dispersed is applied so as to cover each piece arranged on the second base sheet 82 . Here, a phenyl-based resin, which is the second resin 32 in which SiO ₂ is dispersed as a light diffusion material, is compression-molded so as to cover the periphery and upper surface of each individual piece. The second resin 32 is cured in this state to form the translucent member 30 .

Further, if necessary, the upper surface of the cured translucent member 30 is ground to form a predetermined thickness. In the example shown in FIG. 14, the upper surface of the translucent member 30 is mechanically ground with a grinder or the like. In addition, when the thickness can be controlled by adjusting the amount of the second resin 32 at the time of forming the translucent member 30, the mechanical grinding process can be omitted.

Furthermore, a light shielding layer 40 is formed on the wavelength conversion member 20 . For example, as shown in FIG. 15, a third resin 41 in which a light-reflecting material is dispersed is applied to the top and side surfaces of the forming body including the wavelength converting member 20 provided with the translucent member 30 . Here, a phenyl-based resin, which is the third resin 41 in which TiO ₂ is dispersed as a light-reflecting material, is compression-molded around the forming body. In this state, the third resin 41 is cured to form the light shielding layer 40 .

Further, transfer and back grinding are performed. For example, as shown in FIG. 16, the formed body is peeled off from the second base sheet 82 and transferred onto the second UV tape 92 so that the fourth resin 52 side, which will be the light reflective layer 50, faces upward.

Furthermore, the exposed surfaces of the electrodes 12 are protected. Here, as shown in FIG. 17, a terminal protective film 14 is formed by sputtering or the like. Au or the like can be used for the terminal protective film 14.

Furthermore, a metal film 60 is formed for terminal protection. Here, after separating the light emitting elements as shown in FIG. 18, a metal film 62 is formed on the upper surface of the formed body where the end faces of the electrodes 12 are exposed from the light reflective layer 50, as shown in FIG. Metal coating 62 is formed to be electrically connected to electrode 12 . The metal film 62 is formed by sputtering, vapor deposition, atomic layer deposition (ALD), metal organic chemical vapor deposition (MOCVD), plasma CVD (Plasma-Enhanced Chemical Vapor Deposition; PECVD) method, atmospheric pressure plasma deposition method, or the like.

For the metal coating 62, the outermost layer is preferably made of a platinum group element metal such as Au or Pt. Also, Au, which has good solderability, can be used for the outermost surface. The metal film may be composed of only one layer of a single material, or may be composed of laminated layers of different materials. It is particularly preferable to use a metal film with a high melting point, such as Ru, Mo and Ta. In addition, by providing these high-melting-point metals between the electrode 12 and the outermost layer of the light-emitting element 10, diffusion of Sn contained in the solder to the electrode 12 and layers close to the electrode 12 can be reduced. can be a diffusion prevention layer capable of Ni/Ru/Au, Ti/Pt/Au and the like are given as examples of laminated structures having such a diffusion barrier layer. Also, the thickness of the diffusion prevention layer (eg, Ru) is preferably about 10 Å to 1000 Å.

Various thicknesses of the metal coating 62 can be selected. The thickness can be set to such a degree that laser ablation can occur selectively. For example, the thickness is preferably 1 μm or less, more preferably 1000 Å or less. Moreover, it is preferable that the thickness be such that corrosion of the electrode 12 can be reduced, for example, 5 nm or more. Here, the thickness of the metal film 62 means the total thickness of the plurality of layers when the metal film is formed by laminating a plurality of layers.

A portion of the metal coating 62 is then removed. Here, as shown in FIGS. 19 and 20, the metal film 62 is irradiated with laser light to provide an inter-electrode slit without a metal film as an insulating region. A region of the fourth resin 52 serving as an insulating region provided between the pair of electrodes 12 of the light emitting element 10 is irradiated with the laser light. The laser beam is irradiated not only between the pair of electrodes 12 of the light emitting element 10 but also near the electrodes 12 to split or remove the metal film 62 to form the metal film 60 with a predetermined pattern.

The insulating region of the inter-electrode slit has substantially the same width as the width between the electrodes 12 of the light emitting element 10 . The insulating regions are freed of the metal coating 62 by laser ablation. The metal film 62 is removed in the insulating region, and the fourth resin 52 is exposed in a slit shape between the pair of electrodes 12 of the light emitting element 10 .

The laser light can irradiate the metal coating 62 by moving the irradiation spot continuously or step by step on the member. The laser light may be applied continuously or may be applied in pulses. The intensity of the laser beam, the diameter of the irradiation spot, and the moving speed of the irradiation spot are determined in consideration of the thermal conductivity of the fourth resin 52 and the metal coating 62, the difference in thermal conductivity between them, and the like. It can be set so that laser ablation occurs at 62 .

As for the wavelength of the laser light, it is preferable to select a wavelength having a low reflectance with respect to the metal film 60, for example, a wavelength having a reflectance of 90% or less. For example, when the outermost surface of the metal film 60 is Au, it is preferable to use a laser with an emission wavelength shorter than the green region (eg, 550 nm) rather than a red region (eg, 640 nm). Thereby, ablation can be efficiently generated, and mass productivity can be improved.

The light-emitting device 100 can be obtained by dividing the molded body thus obtained into individual pieces of a predetermined size.
[Example 1 and Comparative Example 1]

Next, the light emitting device shown in FIG. 3 was produced as Example 1, and as a comparative example, a white resin layer was formed on the upper surface of the light emitting element 10 instead of the light shielding layer as shown in FIG. A light-emitting device 900 was fabricated in which the wavelength converting member 20 was provided around the element 10 but no translucent member was provided therearound, and the orientation characteristics were measured. The results are shown in FIG. From this graph, it was confirmed that a trough in the relative luminous intensity was formed near the orientation angle of 0°, and that light in the directly upward direction was relatively reduced by the action of the light shielding layer 40 .

The light-emitting device according to the present disclosure can be suitably used as a backlight for televisions, tablets, and liquid crystal display devices, for televisions, tablets, smartphones, smart watches, head-up displays, digital signage, bulletin boards, and the like. It can also be used as a light source for lighting, and can be used for emergency lighting, line lighting, various types of illumination, and in-vehicle installation.

Reference Signs List 100, 400, 500, 600, 900 Light emitting device 10 Light emitting element 12 Electrode 14 Terminal protection film 20 Wavelength conversion member 22 First resin 30 Translucent member 32 Second resin 40 Light blocking layer 41 Third resin 42 Second light shielding layer 50 Light reflective layer 52 Fourth resin 60 Metal film 62 Metal film 70 Light guide plate 80 Base sheet 82 Second base sheet 90 UV tape 92 Third Two UV tape RG…Ring

Claims (8)

a light emitting element having a top surface, a bottom surface having a pair of electrodes, and side surfaces;
a wavelength conversion member that covers the side surface and converts the wavelength of light emitted by the light emitting element to emit light of a different wavelength;
a translucent member covering the outer surface of the wavelength conversion member;
a light shielding layer covering the upper surface of the light emitting element, the upper surface of the wavelength conversion member, and the upper surface of the translucent member;
A light reflective layer covering the lower surface of the light emitting element and the lower surface of the wavelength conversion member,
The light shielding layer directly covers the top surface of the light emitting element, the top surface of the wavelength conversion member, and the top surface of the translucent member ,
The light-emitting device, wherein the light-reflective layer further covers the lower surface of the translucent member . a light emitting element having a top surface, a bottom surface having a pair of electrodes, and side surfaces;
a wavelength conversion member that covers the side surface and converts the wavelength of light emitted by the light emitting element to emit light of a different wavelength;
a translucent member covering the outer surface of the wavelength conversion member;
a light shielding layer covering the upper surface of the light emitting element, the upper surface of the wavelength conversion member, and the upper surface of the translucent member;
a light reflective layer covering the lower surface of the light emitting element and the lower surface of the wavelength conversion member;
and
The light shielding layer directly covers the top surface of the light emitting element, the top surface of the wavelength conversion member, and the top surface of the translucent member,
Using a dimethyl-based resin for the light shielding layer,
A light-emitting device in which a phenyl-based resin is used for the wavelength conversion member and the translucent member. The light emitting device according to claim 1 or 2,
The light-emitting device, wherein the translucent member includes a light diffusing material. The light emitting device according to any one of claims 1 to 3,
A light-emitting device in which the light-shielding layer is composed of a layer containing a light-reflecting resin or a layer containing a metal. The light emitting device according to any one of claims 1 to 4,
A light-emitting device in which the light-shielding layer is made of resin containing TiO ₂ , SiO ₂ , Al ₂ O ₃ or glass filler. The light emitting device according to any one of claims 1 to 5,
A light-emitting device in which the wavelength conversion member includes at least one of a YAG phosphor, a β-sialon phosphor, a KSF-based phosphor, and an MGF-based phosphor. A light emitting device according to claim 6,
A light-emitting device in which the wavelength conversion member contains a phenyl-based resin. A method for manufacturing a light-emitting device,
preparing a light reflecting layer;
preparing a plurality of light emitting elements having a top surface, a bottom surface having a pair of electrodes, and side surfaces;
placing a plurality of the light emitting elements on the upper surface of the light reflecting layer so that the lower surface of the light emitting element is covered with the light reflecting layer except for the regions where the electrodes are provided;
a step of covering the side surfaces of the plurality of light emitting elements and the top surface of the light reflecting layer with a wavelength conversion member that converts the wavelength of light emitted by the light emitting elements to emit light of a different wavelength;
a step of separating the wavelength conversion member among the plurality of light emitting elements to singulate the wavelength conversion member;
a step of covering the outer surface of the separated wavelength conversion member with a translucent member;
a step of directly covering the top surface of the light emitting element, the top surface of the wavelength conversion member, the top surface of the translucent member, and the top surface of the translucent member with a light shielding layer;
A method of manufacturing a light emitting device comprising:

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