JP5915483B2 - Light emitting device and manufacturing method thereof - Google Patents

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

  In a light emitting device having a phosphor layer such as the light emitting devices described in Patent Documents 1 and 2, the light extracted from the vicinity of the outer edge of the phosphor layer is more fluorescent than the light extracted from the vicinity of the center of the phosphor layer. Since the optical path length in the body layer is large, the ratio of fluorescence is high. Therefore, the color of light extracted from the vicinity of the outer edge of the phosphor layer is different from the color of light extracted from the vicinity of the center, and color unevenness may occur in the light emission of the light emitting device.

  One of the objects of the present invention is to provide a light-emitting device having a phosphor layer above an LED chip, in which color unevenness is suppressed, and a method for manufacturing the same.

To achieve the above object, in one aspect of the present invention, a step of mounting an LED chip on a substrate, and a first layer of a dam material surrounding the LED chip before or after mounting the LED chip Forming the phosphor layer on the LED chip after forming the first layer; and covering the upper surface of the outer edge of the phosphor layer so as to cover the upper surface of the dam material. seen containing a step of forming a second layer on said first layer having a non-translucent, the said first layer and said second layer is formed by screen printing, the light emitting device A manufacturing method is provided.

  In the manufacturing method of the light emitting device, an absorption layer that absorbs light emitted from the LED chip is formed on an upper surface of an outer edge portion of the phosphor layer, and the second layer is formed through the absorption layer. You may form so that the upper surface of the outer edge part of a fluorescent substance layer may be covered.

  In the manufacturing method of the light emitting device, a reflective layer that reflects light emitted from the LED chip is formed on an upper surface of an outer edge portion of the phosphor layer, and the second layer is formed through the reflective layer, You may form so that the upper surface of the outer edge part of a fluorescent substance layer may be covered.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device which has the fluorescent substance layer above LED chip, and the color nonuniformity was suppressed, 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. FIG. 2 is a vertical sectional view showing a modification of the light emitting device according to the first embodiment. 3A to 3D are vertical cross-sectional views illustrating manufacturing steps of the light emitting device according to the first embodiment. FIG. 4 is a vertical cross-sectional view of the light emitting device according to the second embodiment. FIG. 5 is a vertical sectional view of the light emitting device according to the third 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 phosphor layer 15 above the LED chip 12, a dam material 13 surrounding the LED chip 12, a dam material 13, and the LED chip 12. And a sealing material 14 embedded between them. The light emitting device 10 can be applied to a vehicle headlight and lighting application as, for example, a sandwiched directional LED light source.

  The dam material 13 has a first layer 13a and a second layer 13b on the first layer 13a. The second layer 13b has non-translucency and covers the upper surface of the outer edge portion of the phosphor layer 15 (the surface on the opposite side of the substrate 11).

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

  The LED chip 12 may be a face-up type or a face-down type. The LED chip 12 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 first layer 13a and the second layer 13b of the dam material 13 are made of, for example, a resin such as a silicone resin or an epoxy resin containing light reflective particles such as titanium dioxide. The first layer 13 a and the second layer 13 b have a white color and reflect 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. Further, the sealing material 14 may be composed of the above material alone, but may contain a filler that refracts and scatters light, for example, SiO ₂ , ZnO ₂ , sapphire, etc. A reflective filler such as TiO ₂ , ZnO, BaSO ₄ , and alumina may be contained. Further, it may contain a filler having better thermal conductivity than the sealing material 14, for example, GaN, AlN, MgO, BN and the like. Furthermore, among the fillers, only one type may be included in the sealing material 14, but by including two or more types, suitable light extraction properties and heat dissipation properties can also be obtained.

  The phosphor layer 15 is a plate-like layer, and is made of, for example, a single crystal phosphor, a ceramic phosphor, an organic material such as a resin containing phosphor particles, or an inorganic material such as glass.

  The phosphor contained in the phosphor layer 15 absorbs the energy of light emitted from the LED chip 12 and emits fluorescence. A color mixture of the color of light emitted from the LED chip 12 and transmitted to the outside through the phosphor layer 15 and the color of fluorescence emitted from the phosphor become the emission color of the light emitting device 10. For example, when the emission color of the LED chip 12 is blue and the emission color of the phosphor is yellow, the emission color of the light emitting device 10 is white.

  If light is directly extracted from the vicinity of the outer edge portion of the phosphor layer 15, the light has a longer optical path length in the phosphor layer 15 than light extracted from the vicinity of the center of the phosphor layer 15, so The ratio is high. Therefore, the color of light extracted from the vicinity of the outer edge of the phosphor layer 15 is different from the color of light extracted from the vicinity of the center, and color unevenness may occur in the light emission of the light emitting device 10. For example, when the emission color of the LED chip 12 is blue and the emission color of the phosphor is yellow, the light extracted from the vicinity of the outer edge of the phosphor layer 15 is stronger in yellow than the light extracted from the vicinity of the center. Become.

  However, in the present embodiment, the outer edge portion of the phosphor layer 15 is covered with the second layer 13b on the upper surface and covered with the first layer 13a on the side surface. Therefore, the light emitted from the LED chip 12 and passing through the outer edge of the phosphor layer 15 is reflected by the second layer 13b or the first layer 13a and is not directly extracted outside. Since the intensity of the light reflected by the second layer 13b or the first layer 13a decreases as the reflection is repeated, unevenness in the light emission of the light emitting device 10 is suppressed.

  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 layer 15, irregularities may be provided on the upper surface of the phosphor layer 15. The phosphor layer 15 may have a multilayer structure in which layers having different refractive indexes are stacked. In this case, in order to reduce the reflection of light emitted from the LED chip 12, it is preferable to stack the layers so that the refractive index decreases from the lower side (the LED chip 12 side) to the upper side. Further, irregularities may be provided at the interface of each layer.

  FIG. 2 is a vertical sectional view illustrating a modification of the light emitting device 10. As shown in FIG. 2, the light emitting device 10 may have a sealing material 16 between the LED chip 12 and the phosphor layer 15. The material of the sealing material 16 and the material of the sealing material 14 may be the same or different.

  In order to improve the light extraction efficiency of the light emitting device 10, the sealing material 16 on the LED chip 12 preferably has a high refractive index in order to reduce reflection of light emitted from the LED chip 12. The side sealing material 14 preferably has a low refractive index in order to increase reflection of light emitted from the LED chip 12. For this reason, when the material of the sealing material 16 and the material of the sealing material 14 are different, the refractive index of the sealing material 16 is preferably higher than the refractive index of the sealing material 14.

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

  3A to 3D are vertical cross-sectional views illustrating manufacturing steps of the light emitting device 10 according to the first embodiment.

  First, as shown in FIG. 3A, the LED chip 12 is mounted on the substrate 11 to form the first layer 13 a of the dam material 13. Either the mounting of the LED chip 12 or the formation of the first layer 13a may be first.

  The first layer 13a is formed by, for example, installing a resin by screen printing or discharging with a dispenser, and then heating and curing the resin. In particular, it is preferable to use screen printing with excellent dimensional accuracy.

  Next, as shown in FIG. 3B, 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. 3C, the phosphor layer 15 is installed above the LED chip 12. At this time, when the height of the first layer 13a is higher than the height of the LED chip 12, as shown in FIG. 3 (c), the phosphor layer 15 has a lower surface and a side surface of the outer edge portion of the first layer 13a. It is installed in contact with the layer 13a. On the other hand, when the height of the first layer 13a is lower than the height of the LED chip 12, the phosphor layer 15 does not contact the first layer 13a. In this case, the second layer 13b formed in the next step is formed so as to cover the side surface of the phosphor layer 15 and the upper and lower surfaces of the outer edge portion.

  Next, as shown in FIG. 3D, the second layer 13 b of the dam material 13 is formed on the first layer 13 a so as to cover the upper surface of the outer edge portion of the phosphor layer 15. Here, since it is required to appropriately cover the upper surface of the outer edge portion of the phosphor layer 15, the second layer 13b is preferably formed by screen printing with excellent dimensional accuracy.

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

  FIG. 4 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 phosphor layer 15 above the LED chip 12, a dam material 23 surrounding the LED chip 12, a dam material 23, and the LED chip 12. And a sealing material 14 embedded between them.

  The dam material 23 has a first layer 23a and a second layer 23b on the first layer 23a. The second layer 23 b is non-translucent and covers the upper surface of the outer edge portion of the phosphor layer 15.

  The first layer 23a of the dam material 23 is made of the same material as that of the first layer 13a of the first embodiment.

  The second layer 23b of the dam material 23 is, for example, a resin such as a silicone-based resin or an epoxy-based resin containing light-absorbing particles such as carbon black, graphite, Fe, or a composite oxide of (Cu, Cr, Zn). Consists of. The second layer 23 b has a black color and absorbs light emitted from the LED chip 12.

  In the present embodiment, the outer edge portion of the phosphor layer 15 is covered with the second layer 23b on the upper surface. Therefore, the light emitted from the LED chip 12 and passing through the outer edge portion of the phosphor layer 15 is absorbed by the second layer 23b and is not directly extracted outside. For this reason, the uneven color of the light emission of the light-emitting device 20 is suppressed.

[Third Embodiment]
The third embodiment differs from the first embodiment in that a coating layer is formed on the outer edge of the phosphor layer. The description of the same points as in the first embodiment will be omitted or simplified.

  FIG. 5 is a vertical sectional view of the light emitting device according to the third embodiment. The light emitting device 30 includes a substrate 11, an LED chip 12 mounted on the substrate 11, a phosphor layer 15 above the LED chip 12, a dam material 13 surrounding the LED chip 12, a dam material 13, and the LED chip 12. And a covering layer 31 provided between the upper surface of the phosphor layer 15 and the second layer 13b.

  The dam material 13 is the same as that of the first embodiment.

  The covering layer 31 is a layer that covers the upper surface of the outer edge portion of the phosphor layer 15, and is an absorption layer that absorbs light emitted from the LED chip 12 or a reflective layer that reflects light emitted from the LED chip 12.

When the coating layer 31 is an absorption layer, it is made of, for example, a black paint such as carbon black, graphite, Fe, or a composite oxide of (Cu, Cr, Zn). When the coating layer 31 is a reflective layer, it is made of, for example, a metal paste such as Ti, Al, or Ag, or a white paint such as TiO ₂ , ZnO, Al ₂ O ₃ , or BaSO ₄ .

  In the present embodiment, the outer edge portion of the phosphor layer 15 is covered with the coating layer 31 on the upper surface. Therefore, the light emitted from the LED chip 12 and passing through the outer edge portion of the phosphor layer 15 is absorbed or reflected by the coating layer 31 and is not directly extracted outside. For this reason, uneven color emission of the light emitting device 30 is suppressed.

(Effect of embodiment)
According to the first to third embodiments, it is possible to prevent light emitted from the LED chip from being directly taken out from the outer edge portion of the phosphor layer, and to suppress uneven color emission of the light emitting device.

  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.

  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, 30 Light-emitting device 11 Substrate 12 LED chip 13, 23 Dam material 13a, 23a First layer 13b, 23b Second layer 15 Phosphor layer 31 Covering layer

Claims (3)

Mounting the LED chip on the substrate;
Before or after mounting the LED chip, forming a first layer of dam material surrounding the LED chip on the substrate;
After forming the first layer, placing a phosphor layer above the LED chip;
Forming a non-translucent second layer of the dam material on the first layer so as to cover the upper surface of the outer edge portion of the phosphor layer;
Only including,
The method for manufacturing a light emitting device, wherein the first layer and the second layer are formed by screen printing . Forming an absorption layer that absorbs light emitted from the LED chip on the upper surface of the outer edge of the phosphor layer;
The second layer is formed so as to cover an upper surface of an outer edge portion of the phosphor layer through the absorption layer.
The manufacturing method of the light-emitting device of Claim 1. Forming a reflective layer that reflects light emitted from the LED chip on the upper surface of the outer edge of the phosphor layer;
The second layer is formed so as to cover an upper surface of an outer edge portion of the phosphor layer through the reflective layer.
The manufacturing method of the light-emitting device of Claim 1.

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