JP2017073576A - LED package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem caused by arranging LED chips in a dispersed state, in which light concentrated through a lens has surface luminance nonuniformity and the light having the surface luminance nonuniformity through the lens forms an image.SOLUTION: An LED package of the present invention comprises: a package substrate; a plurality of LED chips mounted on the package substrate and having a semiconductor laminated structure; and a resin configured to seal the plurality of LED chips. The plurality of LED chips closely adhere to one another without a gap therebetween to form one aggregate.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an LED package, and more particularly to an LED package with improved surface luminance unevenness on a light emitting surface.

  In recent years, LEDs have been used as light-emitting devices that replace conventional halogen light bulbs and the like. In addition, a light-emitting device in which a plurality of LED chips are mounted to output uniform and high-luminance light has been reported (for example, Patent Document 1).

  FIG. 1 is a plan view of an LED package of a conventional light emitting device. In the conventional LED package 100, a plurality of LED chips 2 are arranged on the package substrate 1, and the LED chips are connected to the positive electrode side terminal 26 of one LED chip and the negative electrode side terminal 27 of another adjacent LED chip. 32 is electrically connected. A positive side plate 201 and a negative side plate 202 for supplying current to the LED chip 2 are provided on the package substrate 1, and the positive side terminal 26 and the negative side terminal 27 of the LED chip 2 and the plate side wiring, respectively. 31 is connected.

  A plurality of LED chips 2 are dispersed and arranged so as to be substantially circular, and the LED chips 2 are sealed with a sealing resin 3.

  On the other hand, when an LED is used as a light source for a spotlight as an alternative to a halogen light bulb, a lens is arranged on a LED package on which an LED chip is mounted to collect light.

JP 2012-79855 A

  However, when LED chips are dispersed and arranged as in the prior art, non-uniformity (surface brightness unevenness) occurs in the light collected through the lens, and light having surface brightness unevenness is directly imaged through the lens. There was a problem. That is, when each LED chip emits light, because there is a gap between the LED chips, the brightness of the light is alternately repeated, so that the brightness of the light clearly appears when it is incorporated into the lighting device. There was a problem.

  Further, it is conceivable to include a scattering agent in the lens in order to suppress the surface luminance unevenness as described above. However, in this case, a part of the light emitted from the LED chip is reflected by the scattering agent and returned to the LED chip side, causing a problem that the light extraction efficiency is lowered.

  Accordingly, an object of the present invention is to provide an LED package that can irradiate uniform light with reduced surface luminance unevenness while arranging a plurality of LED chips.

  The LED package of the present invention includes a package substrate, a plurality of LED chips mounted on the package substrate and having a semiconductor stacked structure, and a resin for sealing the plurality of LED chips, and the plurality of LED chips are mutually connected. It is characterized by closely adhering without gaps to form one aggregate.

  In the LED package of the present invention, it is preferable to further provide a light scattering resin containing a light scattering agent at the periphery of the assembly.

  In the LED package of the present invention, it is preferable to further provide a light scattering resin containing a light scattering agent in a gap formed between adjacent semiconductor laminated structures.

  As for the LED package of this invention, it is preferable that the unevenness | corrugation is formed in the outer peripheral part of the LED board which comprises an LED chip.

  The LED package of the present invention is provided in a gap formed between the periphery of the assembly and the adjacent semiconductor laminated structure, and is formed on the planarization layer that forms a flat surface on the surface of the assembly. It is preferable to further have a phosphor layer.

  By using the LED package of the present invention, it is possible to irradiate uniform light while arranging a plurality of LED chips.

It is a top view of the conventional LED package. It is a top view of the LED package which concerns on Example 1 of this invention. It is the top view and sectional drawing of the LED chip mounted in the LED package which concerns on Example 1 of this invention. It is the top view and sectional drawing of an LED package which concern on Example 1 of this invention. It is the top view and sectional drawing of an LED package which concern on Example 2 of this invention. It is the top view and sectional drawing of the LED package which concern on the modification of Example 2 of this invention. It is the top view and sectional drawing of an LED package which concern on Example 3 of this invention. It is the top view and sectional drawing of the LED package which concern on Example 4 of this invention. It is the top view and sectional drawing of the LED package which concern on Example 5 of this invention.

  Hereinafter, an LED package according to the present invention will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the invention described in the claims and equivalents thereof.

[Example 1]
First, an LED package according to Example 1 of the present invention will be described. FIG. 2 shows a plan view of the LED package according to the first embodiment of the present invention. An LED package 101 according to the first embodiment includes a package substrate 1, a plurality of LED chips 2 mounted on the package substrate 1 and having a semiconductor stacked structure, and a resin 3 that seals the plurality of LED chips 2. The plurality of LED chips 2 are characterized by being in close contact with each other and forming one aggregate.

  A positive side plate 201 and a negative side plate 202 for supplying current to the LED chip 2 are provided on the package substrate 1, and the positive side terminal 26 and the negative side terminal 27 of the LED chip 2 and the plate side wiring, respectively. 31 is connected.

  The LED package 101 according to the first embodiment shown in FIG. 2 shows an example in which 18 LED chips 2 are mounted. These LED chips are connected in series. In the LED chips, the positive electrode side terminal 26 of one LED chip and the negative electrode side terminal 27 of another adjacent LED chip are electrically connected by a wiring 32.

  As will be described later, a semiconductor multilayer structure is formed on the LED chip 2 in FIG. 2, but the outermost semiconductor layer constituting the semiconductor multilayer structure is located on the outermost side of the LED substrate constituting the LED chip. Since the n-type semiconductor layer 22 is formed on the inner side of the end portion of the n-type semiconductor layer, the n-type semiconductor layer is present on the outermost side in order to clarify that the semiconductor laminated structure between adjacent LED chips is not in contact with each other. 22 is shown as a representative.

  Next, the configuration of the LED chip will be described. FIG. 3 is a plan view and a cross-sectional view of an LED chip mounted on the LED package according to the first embodiment. FIG. 3A shows a plan view of the LED chip 2, and FIG. 3B shows a cross-sectional view taken along line AA of FIG. 3A. As shown in FIG. 3B, the LED chip 2 includes a semiconductor laminated structure 20 including a light emitting layer on an LED substrate 21 made of sapphire. The semiconductor stacked structure 20 includes an n-type semiconductor layer 22, a light emitting layer 23, and a p-type semiconductor layer 24. The n-type semiconductor layer 22 is provided with a negative electrode side terminal 27, and the p-type semiconductor layer 24 is provided with a positive electrode side terminal 26 via a transparent conductive layer 25 made of ITO.

  As is clear from the cross-sectional view of FIG. 3B, in the LED chip 2 mounted on the LED package 101 according to the first embodiment, the end of the n-type semiconductor layer 22 constituting the semiconductor multilayer structure 20 is the LED substrate 21. Is formed on the inner side by a predetermined distance d. With such a configuration, even if a plurality of LED chips are brought into close contact with each other, the semiconductor multilayer structure 20 can operate normally because it does not contact the semiconductor multilayer structure of other adjacent LED chips.

  Further, when a voltage is applied to the positive electrode side terminal 26 and the negative electrode side terminal 27 of the LED chip 2, light is emitted from the light emitting layer 23, but the light is emitted not only in the vertical direction LV of the LED chip 2 but also in the horizontal direction LH. Is done. In the other examples described later, the case where the LED chip 2 having the structure shown in FIG. 3 is mounted is described as an example.

  The top view and sectional drawing of the LED package which concern on Example 1 of this invention are shown in FIG. The configuration of the LED package according to the first embodiment shown in FIG. 4A is the same as that of FIG. 2, but the positive electrode plate 201 and the negative electrode plate 202 are omitted to simplify the description, and the boundary of the package substrate 1 is omitted. Lines are also omitted.

  FIG. 4B shows a cross-sectional view taken along the line BB in FIG. A phosphor layer 4 is formed on the semiconductor multilayer structure 20 and the package substrate 1 constituting the LED chip 2. The phosphor layer 4 is made of a resin in which the phosphor is uniformly kneaded. When a nitride compound semiconductor that emits blue light is used as the LED chip, yttrium aluminum activated with cerium as the phosphor is used. -Pseudo white light can be obtained by using a garnet (YAG) phosphor. The concentration of the YAG phosphor is preferably about 4.5 wt%. The combination of the emission color of the LED chip and the phosphor is not limited to the above.

  Next, a detailed configuration of the LED chips that are brought into close contact with each other will be described. Assume that five LED chips 2a to 2e are arranged on the line BB as shown in FIG. If attention is paid to the arrangement of the LED substrates 21a to 21e and the semiconductor laminated structures 20a to 20e constituting the LED chips 2a to 2e at this time, the LED substrates 21a to 21e are in close contact with each other as shown in FIG. On the other hand, the semiconductor stacked structures 20a to 20e are not in close contact with each other and have a gap. By adopting such a configuration, even if the LED chips 2a to 2e are brought into close contact with each other, the adjacent semiconductor stacked structures 20a to 20e are not in contact with each other, so that the adjacent semiconductor stacked structures are electrically insulated and operate normally. can do.

  According to the LED package according to the first embodiment of the present invention, a plurality of LED chips are mounted in close contact with each other so as to form a single assembly (LED chip group), so that there is little surface luminance unevenness. Light with uniform brightness can be irradiated.

  Furthermore, since the plurality of LED chips are closely attached to each other without any gap, the shape of the light source can be changed to a desired shape by changing the arrangement of the LED chips. For example, when the shape of the LED chip assembly is a circle or an ellipse, the shape of the light source can be a circle or an ellipse.

  In addition, according to the present invention, the LED chip is closely adhered to form an aggregate to reduce unevenness in the surface brightness of the light emitted from the LED chip, so there is no need to include a light scattering agent in the lens. A clear lens can be used. As a result, the light extraction efficiency can be increased as compared with the conventional LED irradiation device in which the scattering agent is contained in the lens.

[Example 2]
Next, an LED package according to Example 2 of the present invention will be described. In FIG. 5, the top view and sectional drawing of the LED package which concern on Example 2 of this invention are shown. As shown in FIG. 5A, the LED package 102 according to the second embodiment includes a package substrate 1, a plurality of LED chips 2 mounted on the package substrate 1 and having a semiconductor stacked structure 20, and a plurality of LED chips 2. And a plurality of LED chips 2 are closely adhered to each other to form one aggregate, and a light scattering resin 5 including a light scattering agent 51 is provided at the periphery of the aggregate. Furthermore, it is characterized in that it is provided.

  When the light scattering resin 5 is not provided, the shape of the LED chip 2 is rectangular, so that the shape of the peripheral portion of the aggregate has irregularities. As a result, the shape of the periphery of the light emitted from the aggregate and imaged through the lens also has irregularities. On the other hand, by providing the light scattering resin 5 including the light scattering agent 51 in the peripheral part of the aggregate, the combined light of the scattered light from the light scattering resin and the light from the LED chip aggregate is coupled through the lens. As a result, the shape of the obtained light can be a circle or an ellipse having no irregularities in the peripheral portion.

  FIG. 5B shows a cross-sectional view taken along the line CC in FIG. As shown in FIG. 5A, when three LED chips 2f to 2h are arranged on CC, the LED substrates 21f to 21h are in close contact with each other, whereas the semiconductor stacked structure 20f ˜20h is the same as in Example 1 in that they are not in contact with each other.

  In the LED package according to the second embodiment, since the light scattering resin 5 including the light scattering agent 51 is provided in the periphery of the assembly, a part of the lateral light emitted from the LED chip is reflected in the vertical direction. be able to. Specifically, as shown in FIG. 5B, the horizontal light LH emitted from the semiconductor laminated structure 20h constituting the LED chip 2h is reflected by the light scattering agent 51 included in the light scattering resin 5. The light LV1 in the vertical direction is reflected in the vertical direction of the package substrate 1. As a result, the light emitted in the horizontal direction of the LED chip can be used effectively, so that the light extraction efficiency can be improved, and the shape of the light source is made closer to a desired shape such as a circle or an ellipse. Can do.

  Next, a modification of the LED package according to the second embodiment will be described. FIG. 6 shows a modification of the LED package according to the second embodiment. FIG. 6A is a plan view of an LED package 102 ′ according to a modification of the second embodiment, and FIG. 6B is a cross-sectional view taken along the line DD of FIG. 6A. The LED package 102 'according to the modification of the second embodiment is different from the LED package 102 according to the second embodiment in that the outer periphery of the light scattering resin 6 containing the light scattering agent 61 is circular or elliptical. It is.

  According to the LED package according to the modified example of Example 2, the light scattering resin containing the light scattering agent is arranged around the LED chip assembly, and the shape of the outer periphery of the light scattering resin is a circle or an ellipse. Similar to the LED package according to the second embodiment, the shape of the light source can be made close to a circle or an ellipse.

Example 3
Next, an LED package according to Example 3 of the present invention will be described. In FIG. 7, the top view and sectional drawing of the LED package which concern on Example 3 of this invention are shown. As shown in FIG. 7A, an LED package 103 according to the third embodiment includes a package substrate 1, a plurality of LED chips 2 mounted on the package substrate 1 and having a semiconductor stacked structure 20, and a plurality of LED chips 2. The plurality of LED chips 2 are in close contact with each other to form a single assembly, and a light scattering agent is included in the gap formed between adjacent semiconductor stacked structures. It is characterized in that a light scattering resin 7 is further provided.

  FIG. 7B is a cross-sectional view taken along the line DD of FIG. As shown in FIG. 7A, when five LED chips 2a to 2e are arranged on DD, the LED substrates 21a to 21e are in close contact with each other without any gap, whereas the semiconductor laminated structure 20a. ˜20e is the same as in Example 1 in that they are not in contact with each other. In the LED package 103 according to the third embodiment, the light scattering resin 7 including the light scattering agent 71 is disposed in a gap formed between adjacent semiconductor stacked structures such as between the semiconductor stacked structures 20a and 20b. It is characterized by.

  The LED chip 2 emits light not only in the vertical direction LV but also in the horizontal direction LH. The light emitted in the horizontal direction LH is scattered by the light scattering agent 71 included in the light scattering resin 7, and a part of the light emitted in the horizontal direction LH is emitted toward the vertical direction LV2. In the case where the light scattering resin 7 containing the light scattering agent is not provided, the light emitted in the horizontal direction LH from the semiconductor multilayer structure 20c is incident on the adjacent semiconductor multilayer structure 20d and then absorbed and can be extracted outside. However, according to the LED package 103 according to the third embodiment, the light emitted in the horizontal direction, which could not be used until now, can be extracted, so that the light extraction efficiency can be improved as compared with the conventional case.

Example 4
Next, an LED package according to Embodiment 4 of the present invention will be described. In FIG. 8, the top view and sectional drawing of the LED package which concern on Example 4 of this invention are shown. As shown in FIG. 8A, the LED package 104 according to the fourth embodiment includes a package substrate 1, a plurality of LED chips 2 mounted on the package substrate 1 and having a semiconductor stacked structure 20, and a plurality of LED chips 2. The plurality of LED chips 2 are closely adhered to each other to form one aggregate, and further, the unevenness 28 is formed on the outer peripheral portion of the LED substrate constituting the LED chip 2. It is characterized by being formed. The unevenness 28 can be formed by, for example, a dry etching method.

  FIG. 8B shows a cross-sectional view taken along line E-E in FIG. As shown in FIG. 8A, when two LED chips 2i, 2j are arranged on EE, the LED substrates 21i, 21j are in close contact with each other, whereas the semiconductor laminated structure 20i , 20j are not in contact with each other, as in the first embodiment. The LED package 104 according to the fourth embodiment is different from the LED package 101 according to the first embodiment in that irregularities 28i, 28j are formed on the outer peripheral portions of the LED substrates 21i, 21j constituting the LED chips 2i, 2j. ing.

  As shown in FIG. 8B, light is emitted from the semiconductor stacked structure 20i not only in the vertical direction LV but also in the direction L1 of the LED substrate 21i. The light emitted in the L1 direction is reflected at the interface between the LED substrate 21i and the package substrate 1, and part of the light is incident on the unevenness 28i formed on the LED substrate 21i. Since light is easily scattered by the unevenness 28i, the light emitted in the vertical direction LV3 can be increased by providing the unevenness 28i.

  As described above, according to the LED package according to the fourth embodiment, a part of the light incident on the LED substrate from the semiconductor multilayer structure 20 is obtained by the unevenness 28 provided on the outer peripheral portion of the LED substrate 21 constituting the LED chip. Since the light can be extracted outside, the light extraction efficiency can be increased.

Example 5
Next, an LED package according to Embodiment 5 of the present invention will be described. In FIG. 9, the top view and sectional drawing of the LED package which concern on Example 5 of this invention are shown. As illustrated in FIG. 9A, the LED package 105 according to the fifth embodiment includes a package substrate 1, a plurality of LED chips 2 mounted on the package substrate 1 and having a semiconductor stacked structure 20, and a plurality of LED chips 2. And the plurality of LED chips 2 are closely adhered to each other to form one aggregate, and a gap formed between the peripheral portion of the aggregate and the adjacent semiconductor laminated structure And is characterized in that it further includes a planarizing layer 8 that forms a flat surface on the surface of the aggregate, and a phosphor layer 4 formed on the planarizing layer.

  FIG. 9B shows a cross-sectional view taken along line FF in FIG. As shown in FIG. 9A, when five LED chips 2a to 2e are arranged on the FF, the LED substrates 21a to 21e are in close contact with each other with no gap, whereas the semiconductor laminated structure 20a. ˜20e is the same as in Example 1 in that they are not in contact with each other. In the LED package 105 according to the fifth embodiment, the planarization layer 8 provided in the gap formed between the peripheral portion of the assembly and the adjacent semiconductor stacked structure and forming a flat surface on the surface of the assembly, The LED package 101 according to the first embodiment is different from the LED package 101 according to the first embodiment in that the phosphor layer 4 is further formed on the conversion layer 8.

  A phosphor material may be used to convert and use the wavelength of light emitted from the LED chip 2. For example, when the light emitted from the LED chip is blue, white light can be obtained by providing a yellow phosphor layer on the LED chip. Here, the phosphor layer is formed by adding a phosphor material into a resin, but there is a problem that the phosphor material tends to settle. Therefore, if the LED chip aggregate has irregularities, the phosphor material settles in the depressions, making it difficult to obtain a desired density on the surface of the light emitting layer of the phosphor material, resulting in light color unevenness. May end up. Therefore, in the LED package according to Example 5, as shown in FIG. 9B, first, the surface of the assembly is flat in the gap formed between the peripheral portion of the assembly and the adjacent semiconductor stacked structure. The planarizing layer 8 that forms the surface is formed, and then the phosphor layer 4 containing the phosphor material 42 is formed on the planarizing layer 8. As shown in FIG. 9B, in this embodiment, the side wall 41 is formed before the phosphor layer 4 is formed, but the phosphor layer can be flattened even without the side wall. Side walls are not necessarily required.

  According to the LED package of Example 5, the surface of the assembly of LED chips is flattened, and the phosphor layer is disposed thereon, so that the phosphor material settles in the phosphor layer. However, the concentration of the phosphor material on the surface of the light emitting layer of the LED chip can be set to a desired concentration.

  In the above embodiments, the end of the semiconductor multilayer structure is formed on the inner side than the end of the LED substrate in the LED chip, and the semiconductor multilayer structure is not in contact even when the LED chips are brought into close contact with each other. However, it is not limited to such a structure. That is, it is only necessary that a plurality of LED chips are brought into close contact with each other so as not to be in electrical contact with the adjacent semiconductor laminated structure. For example, an insulating layer may be provided around the semiconductor stacked structure.

  In the above embodiment, the face-up type LED chip is described as an example, but a face-down type LED chip may be used.

  In the above-described embodiment, an example in which 18 LED chips are brought into close contact with each other has been shown.

DESCRIPTION OF SYMBOLS 1 Package substrate 2 LED chip 3 Sealing resin 4 Phosphor layer 5 Light scattering resin 6 Light scattering resin 7 Light scattering resin 8 Planarization layer 101-105 LED package 20 Semiconductor laminated structure 21 LED substrate

Claims (5)

A package substrate;
A plurality of LED chips mounted on the package substrate and having a semiconductor laminated structure;
A resin for sealing the plurality of LED chips,
The plurality of LED chips are closely adhered to each other to form one aggregate,
LED package characterized by the above.   The LED package according to claim 1, further comprising a light scattering resin containing a light scattering agent in a peripheral portion of the assembly.   The LED package according to claim 1, wherein a light scattering resin containing a light scattering agent is further provided in a gap formed between adjacent semiconductor laminated structures.   The LED package according to any one of claims 1 to 3, wherein irregularities are formed on an outer peripheral portion of an LED substrate constituting the LED chip. A planarization layer provided in a gap formed between a peripheral portion of the aggregate and an adjacent semiconductor laminated structure, and forming a flat surface on the surface of the aggregate;
A phosphor layer formed on the planarizing layer;
The LED package according to claim 1, further comprising:

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