JP2014072212A - Light-emitting device and process of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device, having a phosphor layer above an LED chip, excellent in light-emitting characteristics, and to provide a process of manufacturing the same.SOLUTION: A light-emitting device 10 includes: a substrate 11; an LED chip 12 mounted on the substrate 11; and a phosphor layer 15, on the LED chip 12, having a glass plate 15a that is a plate composed of a translucent inorganic material containing phosphor particles and a phosphor containing resin layer 15b that contains a resin that is in contact with a surface of the glass plate 15a opposite to the substrate 11.

Description

  The present invention relates to a light emitting device and a method for manufacturing the same.

  As a conventional light-emitting device, a light-transmitting material containing phosphor particles and a device having a plate-like phosphor layer made of phosphor crystals above an LED element are known (see, for example, Patent Documents 1 and 2). ).

  According to the light-emitting devices described in Patent Literatures 1 and 2, a mixed color of the color of light directly extracted from the LED element and the color of fluorescence emitted from the phosphor layer is the light-emitting color of the light-emitting device.

JP 2007-123437 A International Publication No. 2009/069671

  One of the objects of the present invention is to provide a light emitting device having a phosphor layer above an LED chip and having excellent light emission characteristics, and a method for manufacturing the same.

  To achieve the above object, in one aspect of the present invention, a substrate, an LED chip mounted on the substrate, a plate material including phosphor particles on the LED chip and made of a light-transmitting inorganic material, and the There is provided a light emitting device having a phosphor layer having a resin layer containing a resin in contact with a surface opposite to the substrate of the plate material.

  In the light emitting device, the phosphor particles may be included in the resin layer.

  In the light emitting device, the phosphor particles may be included in the plate material.

  In the light emitting device, it is preferable that the refractive index of the resin is smaller than the refractive index of the plate member.

  In the light emitting device, the plate material is in contact with the LED chip, the refractive index of the plate material is smaller than the refractive index of the layer in contact with the plate material of the LED chip, and the refractive index of the resin is smaller than the refractive index of the plate material. May be.

  In another aspect of the present invention, a step of mounting an LED chip on a substrate, and a phosphor layer containing phosphor particles on the LED chip and having a plate material and a resin layer in contact with the plate material, And a step of forming the light-emitting device in contact with the chip.

  In the method for manufacturing the light emitting device, the resin layer may be formed on the plate material by compression molding, spin coating, electrostatic coating, electrostatic spraying, or screen printing.

  In the method for manufacturing the light emitting device, the plate material may be bonded to the LED chip by thermocompression bonding.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device which has the fluorescent substance layer above LED chip, and was excellent in the light emission characteristic, and its manufacturing method can be provided.

FIG. 1 is a vertical cross-sectional view of the light emitting device according to the first embodiment. 2A to 2C are vertical cross-sectional views illustrating manufacturing steps of the light emitting device according to the first embodiment. FIG. 3 is a vertical cross-sectional view of the light emitting device according to the second embodiment.

[First Embodiment]
FIG. 1 is a vertical cross-sectional view of the light emitting device according to the first embodiment. The light emitting device 10 includes a substrate 11, an LED chip 12 mounted on the substrate 11, a dam material 13 surrounding the LED chip 12, a sealing material 14 embedded between the dam material 13 and the LED chip 12, And a phosphor layer 15 on the LED chip 12. The light emitting device 10 can be applied to a headlight of a car as a sandwiched directional LED light source, for example.

  The substrate 11 is made of a ceramic such as aluminum oxide (alumina) or aluminum nitride, for example.

  The LED chip 12 is, for example, a flip chip type, and includes an LED chip substrate 12a and a crystal layer 12b on the surface of the LED chip substrate 12a on the substrate 11 side. The crystal layer 12b is formed by epitaxial crystal growth on the LED chip substrate 12a. The crystal layer 12 b has a light emitting layer sandwiched between an n-type semiconductor layer and a p-type semiconductor layer, and the n-type semiconductor layer and the p-type semiconductor layer are connected to a conductive pattern (not shown) on the substrate 11. The light emitted from the LED chip 12 is extracted from the phosphor layer 15 side. The LED chip 12 is not limited to the flip chip type, and may be a face-up type, for example.

  The dam material 13 is made of, for example, a resin such as a silicone resin or an epoxy resin including light reflective particles such as titanium dioxide. The dam material 13 reflects the light emitted from the LED chip 12.

  The sealing material 14 is a member that seals the LED chip 12 and is made of, for example, a resin such as a silicone resin or an epoxy resin, or glass.

  The phosphor layer 15 includes a glass plate 15a and a phosphor-containing resin layer 15b that is in contact with the surface of the glass plate 15a opposite to the substrate 11 (the upper surface in FIG. 1).

The glass plate 15a is made of, for example, low melting point glass such as P ₂ O ₃ , ZnO, Bi ₂ O _{3 and} the upper surface of the LED chip 12 (the surface of the LED chip substrate 12a when the LED chip 12 is a flip chip type). It is thermocompression bonded to. In this case, the glass plate 15 a contacts the LED chip 12. The refractive index of the glass plate 15a is, for example, 1.4 to 2.2. The thickness of the glass plate 15a is, for example, 50 to 200 μm.

  In addition, when installing on the LED chip 12 through an adhesive layer, the glass plate 15a does not need to consist of low melting glass. As the material for the adhesive layer, for example, an acrylic adhesive having a refractive index of approximately 1.5 to 1.7, a silicone adhesive, an epoxy adhesive, or a glass adhesive can be used.

  The phosphor-containing resin layer 15b is made of a resin containing phosphor particles. The resin constituting the phosphor-containing resin layer 15b is, for example, a silicone-based resin, an epoxy-based resin, or a silicone-based and epoxy-based hybrid resin. The refractive index of the resin that constitutes the phosphor-containing resin layer 15b is, for example, 1.4 to 1.6. The thickness of the phosphor-containing resin layer 15b is, for example, 50 to 200 μm.

As the phosphor included in the phosphor-containing resin layer 15b, the following can be used. As the blue phosphor, for example, an aluminate phosphor such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ can be used. Examples of green to orange phosphors include garnet phosphors such as (Y, Tb, Lu) ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , (Ba, Sr) _3. An orthosilicate phosphor such as SiO ₅ : Eu ²⁺ or an oxynitride phosphor such as Ca (Si, Al) ₁₂ (O, N) ₁₆ : Eu ²⁺ , SrSi ₂ O ₂ N ₂ : Eu ²⁺ is used. be able to. As the red phosphor, a nitride phosphor such as (Ca, Sr) AlSiN ₃ : Eu ²⁺ or a fluoride phosphor such as K ₂ SiF ₆ : Mn ⁴⁺ can be used.

  The phosphor contained in the phosphor-containing resin layer 15b absorbs the energy of light emitted from the LED chip 12 and emits fluorescence. A color mixture of light emitted from the LED chip 12 and transmitted through the phosphor-containing resin layer 15 b to the outside and a color of fluorescence emitted from the phosphor becomes a light emission color of the light emitting device 10. For example, when the emission color of the light emitting device 10 is white, (A) an LED chip 12 that emits ultraviolet light or violet light + a blue phosphor, or (B) an LED chip 12 that emits blue light, and (α) a yellow phosphor. , (Β) yellow phosphor + red phosphor, or (γ) green phosphor + red phosphor combinations (6 types in total).

  In order to improve the light extraction efficiency by reducing the reflection of light emitted from the LED chip 12 on the upper surface of the phosphor-containing resin layer 15b, the upper surface of the phosphor-containing resin layer 15b may be provided with unevenness. .

  Since the glass plate 15a is located under the phosphor-containing resin layer 15b, the heat generated from the LED chip 12 is phosphor-containing compared to the case where the phosphor-containing resin layer 15b is directly provided on the LED chip 12. It is difficult to be transmitted to the resin layer 15b, and it is possible to suppress a decrease in fluorescence characteristics due to the temperature rise of the phosphor.

  In order to suppress reflection of light emitted from the LED chip 12 at the interface between the glass plate 15a and the phosphor-containing resin layer 15b, the refractive index of the resin constituting the phosphor-containing resin layer 15b is higher than the refractive index of the glass plate 15a. Small is preferable.

  Further, when the LED chip 12 and the glass plate 15a are in contact, the refractive index of the glass plate 15a is smaller than the refractive index of the layer in contact with the glass plate 15a of the LED chip 12, and the phosphor-containing resin is lower than the refractive index of the glass plate 15a. The refractive index of the resin constituting the layer 15b is preferably small.

  For example, when the LED chip 12 is a flip chip type as shown in FIG. 1 and the LED chip substrate 12a and the glass plate 15a are in contact, the refractive index of the glass plate 15a is smaller than the refractive index of the LED chip substrate 12a. The refractive index of the resin constituting the phosphor-containing resin layer 15b is preferably smaller than the refractive index of the glass plate 15a. For example, when the LED chip substrate 12a is a sapphire substrate having a refractive index of approximately 1.7, the refractive index of the glass plate 15a is preferably less than 1.7. In addition, when the LED chip substrate 12a is a gallium nitride substrate having a refractive index of approximately 2.2, the refractive index of the glass plate 15a is preferably less than 2.2.

  Further, when an adhesive layer for adhering these is provided between the LED chip substrate 12a and the glass plate 15a, the refractive index of the adhesive layer is smaller than the refractive index of the LED chip substrate 12a, and the refractive index of the adhesive layer. It is preferable that the refractive index of the glass plate 15a is smaller than that.

When the LED chip 12 is a flip chip type and the LED chip substrate 12a is a GaN substrate, the refractive index of the LED chip substrate 12a is relatively high at about 2.2, and the LED chip substrate 12a, the glass plate 15a, Reflection is likely to occur at the interface. For this reason, an antireflection film (AR coating) may be provided between the LED chip substrate 12a and the glass plate 15a. This antireflection film is made of, for example, SiO ₂ .

  Below, an example of the manufacturing method of the light-emitting device 10 is shown.

  2A to 2C are vertical cross-sectional views illustrating manufacturing steps of the light emitting device 10 according to the first embodiment.

  First, as shown in FIG. 2A, the LED chip 12 is mounted on the substrate 11 to form the dam material 13. Either the LED chip 12 or the dam member 13 may be formed first.

  The dam material 13 is formed by, for example, installing a resin by screen printing or discharging by a dispenser and then heating and curing the resin.

  Next, as shown in FIG. 2B, a sealing material 14 is formed between the dam material 13 on the substrate 11 and the LED chip 12. The sealing material 14 is formed, for example, by discharging a liquid resin with a dispenser and heating and curing the resin.

  Next, as shown in FIG. 2C, the phosphor layer 15 is installed on the LED chip 12. At this time, the phosphor-containing resin layer 15b may be formed on the glass plate 15a by compression molding, spin coating, electrostatic coating, electrostatic spraying, or the like, and then placed on the LED chip 12, or the glass plate 15a may be LED After installing on the chip 12, the phosphor-containing resin layer 15b may be formed on the glass plate 15a by screen printing or the like.

  When the phosphor layer 15 is directly installed on the LED chip 12, the glass plate 15a can be bonded to the LED chip 12 by thermocompression bonding.

[Second Embodiment]
The second embodiment differs from the first embodiment in the configuration of the phosphor layer. The description of the same points as in the first embodiment will be omitted or simplified.

  FIG. 3 is a vertical cross-sectional view of the light emitting device according to the second embodiment. The light emitting device 20 includes a substrate 11, an LED chip 12 mounted on the substrate 11, a dam material 13 surrounding the LED chip 12, a sealing material 14 embedded between the dam material 13 and the LED chip 12, And a phosphor layer 25 on the LED chip 12.

  The phosphor layer 25 includes a phosphor-containing glass plate 25a and a resin layer 25b in contact with the upper surface (the upper surface in FIG. 3) of the phosphor-containing glass plate 25a.

  The phosphor-containing glass plate 25a is made of the same glass as the glass constituting the glass plate 15a of the first embodiment. The refractive index of the glass which comprises the fluorescent substance containing glass plate 25a is 1.4-2.2, for example. The phosphor-containing glass plate 25a includes phosphor particles. The thickness of the phosphor-containing glass plate 25a is, for example, 50 to 200 μm. As a fluorescent substance contained in the fluorescent substance containing glass plate 25a, the thing similar to the fluorescent substance contained in the fluorescent substance containing resin layer 15b of 1st Embodiment can be used.

  The phosphor contained in the phosphor-containing glass plate 25a absorbs the energy of light emitted from the LED chip 12 and emits fluorescence. A mixed color of the color of light emitted from the LED chip 12 and transmitted through the phosphor-containing glass plate 25a to the outside and the color of fluorescence emitted from the phosphor become the emission color of the light emitting device 10.

  The resin layer 25b is made of the same resin as that constituting the phosphor-containing resin layer 15b of the first embodiment. The refractive index of the resin layer 25b is, for example, 1.4 to 1.6. The thickness of the resin layer 25b is, for example, 50 to 200 μm.

  In order to improve the light extraction efficiency by reducing the reflection of light emitted from the LED chip 12 on the upper surface of the resin layer 25b, the upper surface of the resin layer 25b may be provided with unevenness.

  In order to suppress reflection of light emitted from the LED chip 12 at the interface between the phosphor-containing glass plate 25a and the resin layer 25b, the refractive index of the resin layer 25b is higher than the refractive index of the glass constituting the phosphor-containing glass plate 25a. Small is preferable.

  Furthermore, when the LED chip 12 and the phosphor-containing glass plate 25a are in contact, the refractive index of the phosphor-containing glass plate 25a is smaller than the refractive index of the layer in contact with the phosphor-containing glass plate 25a of the LED chip 12, and the phosphor-containing material is included. The refractive index of the resin constituting the resin layer 25b is preferably smaller than the refractive index of the glass plate 25a.

  Further, when the LED chip 12 is a flip chip type as shown in FIG. 3 and the LED chip substrate 12a and the phosphor-containing glass plate 25a are in contact with each other, the phosphor-containing glass plate 25a rather than the refractive index of the LED chip substrate 12a. The refractive index of the resin layer 25b is preferably smaller than the refractive index of the glass constituting the phosphor-containing glass plate 25a. For example, when the LED chip substrate 12a is a sapphire substrate having a refractive index of approximately 1.7, the refractive index of the glass constituting the phosphor-containing glass plate 25a is preferably less than 1.7. Further, when the LED chip substrate 12a is a gallium nitride substrate having a refractive index of approximately 2.2, the refractive index of the glass constituting the phosphor-containing glass plate 25a is preferably less than 2.2.

  Further, when an adhesive layer for adhering these is provided between the LED chip substrate 12a and the phosphor-containing glass plate 25a, the refractive index of the adhesive layer is smaller than the refractive index of the LED chip substrate 12a. It is preferable that the refractive index of the phosphor-containing glass plate 25a is smaller than the refractive index.

(Effect of embodiment)
According to the first and second embodiments, by including the glass plate in the phosphor layer, the strength of the phosphor layer is increased, and deformation during installation can be suppressed. In addition, since the strength of the phosphor layer is maintained even if the phosphor-containing layer (phosphor-containing resin layer or phosphor-containing glass plate) is thinned, the phosphor-containing layer is thinned in the phosphor layer. Light scattering can be reduced and light extraction efficiency can be improved. Light scattering is reduced when the layer containing the phosphor is thinned, because the thickness of the layer containing the phosphor approaches the particle size of the phosphor (mainly distributed to 20 to 30 μm). This is because there is less overlap.

  Further, by thinning the phosphor-containing layer, light scattering in the phosphor layer is reduced, so that color unevenness and luminance unevenness of the light-emitting device can be reduced. Further, by reducing the thickness of the phosphor-containing layer, heat generated from the phosphor layer can be efficiently released, and the reliability of the light-emitting device can be improved.

  Further, when the LED chip and the glass plate are in contact, the refractive index of the glass constituting the glass plate is smaller than the refractive index of the layer in contact with the glass plate of the LED chip, and the resin constituting the resin layer is lower than the refractive index of the glass By reducing the refractive index of the light emitting device, the reflection of light emitted from the LED chip is reduced compared with the case where only the resin layer is installed on the LED chip and the case where only the glass plate is installed. The extraction efficiency can be improved.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the glass plate used for the glass plate 15a of the first embodiment or the phosphor-containing glass plate 25a of the second embodiment is a translucent inorganic material other than that disclosed in the above embodiment. The board | plate material which consists of may be sufficient. For example, by using a plate material made of a crystalline material such as sapphire or ZnO, heat generated from the phosphor can be more effectively released to the outside.

  In addition, the constituent elements of the above-described embodiment can be arbitrarily combined without departing from the spirit of the invention. For example, a phosphor layer having the phosphor-containing resin layer 15b of the first embodiment and the phosphor-containing glass plate 25a of the second embodiment may be used.

  Moreover, said embodiment does not limit the invention which concerns on a claim. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

10, 20 Light emitting device 11 Substrate 12 LED chip 15, 25 Phosphor layer 15a Glass plate 15b Phosphor-containing resin layer 25a Phosphor-containing glass plate 25b Resin layer

Claims (8)

A substrate,
An LED chip mounted on the substrate;
A phosphor layer having a resin layer containing a resin material that includes phosphor particles on the LED chip and is made of a translucent inorganic material and a surface of the plate material opposite to the substrate;
A light emitting device. The phosphor particles are included in the resin layer,
The light emitting device according to claim 1. The phosphor particles are included in the plate material,
The light emitting device according to claim 1. The refractive index of the resin is smaller than the refractive index of the plate material,
The light-emitting device of any one of Claims 1-3. The plate material is in contact with the LED chip,
The refractive index of the plate material is smaller than the refractive index of the layer in contact with the plate material of the LED chip,
The refractive index of the resin is smaller than the refractive index of the plate material,
The light emitting device according to claim 4. Mounting the LED chip on the substrate;
Forming a phosphor layer on the LED chip, the phosphor layer including phosphor particles, and having a plate material and a resin layer in contact with the plate material, in contact with the LED chip;
A method for manufacturing a light emitting device, comprising: The resin layer is formed on the plate material by compression molding, spin coating, electrostatic coating, electrostatic spraying or screen printing.
A method for manufacturing a light emitting device according to claim 6. The plate material is bonded to the LED chip by thermocompression bonding.
The manufacturing method of the light-emitting device of Claim 6 or 7.

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