JP2011018704A - Method of forming fine irregularities on surface of sealing member surrounding led chip, and method of manufacturing led lamp including the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of well forming fine irregularities on a surface of a sealing member which surrounds an LED chip.SOLUTION: The method of forming the fine irregularities on the surface of the sealing member which surrounds a semiconductor chip includes steps of making a sheet having the fine irregularities interpose on a sealing member shaping surface of a die in molding the sealing member, and transferring the fine irregularities of the sheet to the surface of the sealing member.

Description

  The present invention relates to an improvement in a method for forming fine irregularities on the surface of a sealing member surrounding an LED chip.

  Conventionally, in an LED lamp in which an LED chip is resin-sealed, the light of the LED chip is totally reflected on the surface of the sealing member, and the light extraction efficiency may be reduced. In order to prevent this, various studies have been conducted on the molding of the sealing member surface. For example, Patent Document 1 discloses an LED lamp in which irregularities are formed on a top surface of a sealing member by a mold or the like when the sealing member is molded. Patent Document 2 discloses an LED lamp in which an uneven film having an uneven pattern is provided on the surface of a sealing member. Patent Document 3 discloses an LED lamp in which a concavo-convex shape is formed on the side surface in addition to the upper surface of the sealing member. Patent Document 4 discloses an LED lamp that is not a sealing member, but includes a fluorescent plate having an uneven surface on the light emission side of the LED chip.

JP 2003-234509 A JP 2008-227456 A JP 2008-300580 A JP 2005-268323 A

In the LED lamps of Patent Documents 1 to 3, the uneven shape on the surface of the sealing member is formed by molding using a mold having an uneven shape on the surface with the sealing member, for example. In this method, as the uneven shape becomes finer, higher releasability is required between the sealing member and the mold, so that it is difficult to form a fine uneven shape favorably. Further, this method is disadvantageous in terms of cost because it is necessary to change the shape of the mold itself in order to change the uneven shape. On the other hand, fine irregularities can be provided by surface-treating the sealing member cured after sealing, but this is not preferable because the number of manufacturing steps increases. Further, it is not preferable to provide a fluorescent plate or the like having fine irregularities after sealing as in the LED lamp of Patent Document 4 because the number of parts increases as the number of manufacturing steps increases.
Therefore, an object of the present invention is to provide a method for satisfactorily forming fine irregularities on the surface of a sealing member surrounding an LED chip. Another object of the present invention is to provide a method for forming a fine unevenness on the surface of a sealing member that surrounds an LED chip, which is easy to change the uneven shape and is advantageous in terms of cost.

In order to achieve the above object, a first aspect of the present invention has the following configuration. That is,
A method of forming fine irregularities on the surface of a sealing member surrounding an LED chip,
When molding the sealing member, a sheet having fine irregularities is interposed between the molding member-equipped surface of the mold and the sealing member, and the fine irregularities of the sheet are formed on the surface of the sealing member. The method of forming fine irregularities on the surface of the sealing member, characterized in that

  According to the method of the first aspect of the present invention, when the sealing member is molded, a sheet having fine irregularities is interposed between the sealing member-attached surface of the mold and the sealing member. The sealing member does not contact the mold. As a result, the releasability between the sealing member and the mold is good, and fine unevenness of the sealing member is well formed. In addition, since the fine irregularities are formed on the surface of the sealing member simultaneously with the molding of the sealing member, the manufacturing process is simplified. Furthermore, since a desired fine uneven shape can be formed by using a sheet having a desired fine uneven shape, it is easy to change the fine uneven shape and the mold itself needs to be changed. This is advantageous in terms of cost.

FIG. 1 is a flowchart of an LED lamp manufacturing method 1 according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the manufacturing method 1. FIG. 3 is a partially enlarged perspective view of the upper surface 20 a of the sheet 20. FIG. 4 is an enlarged partial cross-sectional view of the surface of the sealing member 41 of the LED lamp 50. FIG. 5 is a flowchart of an LED lamp manufacturing method 100 according to another embodiment of the present invention. FIG. 6 is a diagram for explaining the manufacturing method 100. FIG. 7 is a diagram for explaining the manufacturing method 100. FIG. 8 is an enlarged partial cross-sectional view of the first sealing layer 401 and the second sealing layer 403 of the LED lamp 500. 9A is a cross-sectional view of the LED lamp 500a, and FIG. 9B is a cross-sectional view of 500b.

  Hereinafter, a method for forming fine irregularities on the surface of the sealing member surrounding the LED chip of the present invention will be described in detail. In the method of the present invention, when the sealing member is molded, a sheet having fine irregularities is interposed between the molding member-equipped surface of the mold and the sealing member. The material of the sheet is preferably a material having a high releasability with respect to the mold in a high temperature state. For example, ETFE (ethylene-tetrafluoroethylene resin), PTFE (tetrafluoroethylene resin) or the like is adopted as the sheet material. be able to. The fine irregularities of the sheet are provided on the surface facing the sealing member (hereinafter also referred to as “sealing member facing surface”) in the region between the sealing member-shaped surface of the mold and the sealing member. . The shape of the fine unevenness is, for example, an unevenness in which convex portions such as a conical shape, a cylindrical shape, a triangular pyramid shape, a triangular prism shape, a quadrangular pyramid shape, a quadrangular prism shape, a hemispherical shape, or a combination of these shapes are arranged at predetermined intervals. The shape, the cross-sectional shape may be triangular, quadrangular, semi-circular or a combination of these shapes, such as a concavo-convex shape in which linear grooves are arranged at predetermined intervals, an irregular concavo-convex shape made of satin, etc. it can.

  The depth of the concave portion or the height of the convex portion in the fine unevenness is, for example, about 1.0 μm to about 50 μm, preferably about 5.0 μm to about 20 μm, more preferably about 7.5 μm to 15 μm, and most preferably about 10 μm. It is. The interval between the concave or convex portions in the fine irregularities is about 1.0 μm to about 100 μm, preferably about 5.0 μm to about 50 μm, more preferably about 7.5 μm to 30 μm, and most preferably about 20 μm.

  The fine unevenness of the sheet may be provided in the entire region of the sealing member facing surface, or may be provided only in a partial region of the sealing member facing surface. Further, the shape of the fine unevenness, the depth of the concave portion, the height of the convex portion, the interval between the concave portion and the convex portion may be uniform over the entire area of the sealing member facing surface, or a part of the sealing member facing surface. The area may be different from other areas.

The shape of the surface with the sealing member in the mold can be determined in consideration of the type of LED chip to be surrounded, the shape of the LED chip, the required light distribution, and the like. For example, a hemispherical shape, a partial ellipse shape, a partial paraboloid shape with the center of the surrounding LED chip as a focal position, or a rectangular parallelepiped shape formed by combining surfaces parallel to the wall surface of the surrounding LED chip can be used.
The mold preferably has a plurality of surfaces with sealing members, and the sheet has fine irregularities so as to correspond to the plurality of surfaces with sealing members of the mold. This is because a plurality of sealing members can be formed simultaneously.

  The type of mold forming for forming the sealing member is not particularly limited, and an appropriate one can be adopted from known mold forming such as compression molding and injection molding. Among these, it is preferable to employ compression molding. Instead of the release sheet used in the conventional compression molding, the number of steps of the LED lamp manufacturing method including the method of the present invention is reduced by using the above-described sheet having fine irregularities. It is because it can be equivalent.

  When forming the sealing member by compression molding, it is preferable that the sheet having fine light projections is adsorbed by negative pressure to the surface of the mold with the sealing member at the time of compression molding. This is because the sheet and the molding member-equipped surface of the mold come into close contact with each other, and the sealing member can be satisfactorily formed by the molding member-equipped surface of the mold.

  The sealing member may have a multilayer structure. When the sealing member has a multilayer structure, fine irregularities are formed on the surface (interface) of at least one layer. For example, when the sealing member includes a first sealing layer that directly surrounds the LED chip and a second sealing layer that surrounds the first sealing layer, the first sealing layer and the second sealing layer The first fine unevenness may be formed on the interface with the stop layer, and the second fine unevenness may be formed on the surface of the second sealing layer, or the first fine unevenness or the second fine unevenness may be formed. Only one of the fine irregularities may be formed. The first fine unevenness and the second fine unevenness may be the same in the shape of the fine unevenness, the depth of the concave portion, the height of the convex portion, and the interval between the concave portion and the convex portion. One may be different.

In the multilayer sealing member, when the refractive index of the sealing layer located on the inner side (side close to the LED chip) is higher than the refractive index of the sealing layer located on the outer side between two adjacent sealing layers When the fine unevenness is provided at the interface between the inner sealing layer and the outer sealing layer, the light from the LED chip is prevented from being totally reflected at the interface between the inner sealing layer and the outer sealing layer, and the light is extracted. Efficiency is improved.
On the other hand, when the refractive index of the sealing layer located on the inner side (side closer to the LED chip) is lower than the refractive index of the sealing layer located on the outer side of the two adjacent sealing layers, the inner sealing is performed. If fine irregularities are provided at the interface between the outer sealing layer and the outer sealing layer, light is dispersed from the inner sealing layer to the outer sealing layer at the interface, which promotes the mixing of the light from the LED chip and provides a good brightness balance. It becomes. For example, the inner sealing layer can be made of silicone, and the outer sealing layer can be made of epoxy resin or glass having a higher refractive index than silicone. In the multilayer sealing member, it is preferable to provide fine irregularities on the outermost surface of the sealing layer (interface with the air layer). Since the refractive index of the outermost sealing layer is larger than the refractive index of the air layer, total reflection may occur on the surface, but the total reflection is prevented by the fine unevenness and the light extraction efficiency is improved. is there.

2nd aspect of this invention is a manufacturing method of an LED lamp containing the method of the above-mentioned 1st aspect.
A third aspect of the present invention is an LED lamp manufacturing method in which an LED chip is sequentially surrounded by a first sealing member and a second sealing member, and the surface of the first sealing member and / or A method for manufacturing an LED lamp, characterized in that fine irregularities are formed on the surface of a second sealing member by the method of the first aspect described above. Furthermore, in addition to the first sealing member and the second sealing member, the LED chip may be provided by a third sealing member. The third sealing member can be formed in the same manner as the first sealing member or the second sealing member.
Examples of the present invention will be described in detail below.

  FIG. 1 shows a flowchart of a manufacturing method 1 of an LED lamp that is an embodiment of the present invention. FIG. 2 shows a diagram for explaining the manufacturing method 1. As shown in FIG. 2A, first, a mold 10 and a sheet 20 are prepared (step 1 in FIG. 1). The mold 10 includes a lower mold 10a and an upper mold 10b. A hemispherical recess 11 is formed on the surface of the lower mold 10a facing the upper mold 10a, and the wall surface of the recess 11 serves as a sealing member-formed surface 11a. In the vicinity of the recess 11, two suction ports 12 that open to the surface facing the upper mold 10 b are provided. The suction port 12 is connected to a suction machine (not shown). Further, as will be described later, a resin material supply machine (not shown) for injecting a resin material into the concave portion 11 to which the sheet 20 is in close contact is provided in the lower mold 10a.

  The upper mold 10b is substantially flat. The upper mold 10b includes two first suction ports 13 and two second suction ports 14 that open on the surface facing the lower mold 10a. The first and second suction ports 13 and 14 are each connected to a suction machine (not shown). An O-ring 15 is provided on the surface facing the lower mold 10a of the upper mold 10b so as to surround the first and second suction ports 13 and 14 collectively.

  The sheet 20 is disposed between the lower mold 10a and the upper mold 10b. The sheet 20 is a thin film made of ETFE, and fine unevenness is formed on a surface 20a (hereinafter also referred to as “upper surface 20a”) on the upper mold 10b side. A partially enlarged perspective view of the upper surface 20a of the sheet 20 is shown in FIG. As shown in FIG. 3, a plurality of triangular ridges 21 having a triangular cross section are formed over substantially the entire upper surface 20a. The shape of the triangular ridge 21 is a triangular ridge having a top angle θ of about 90 °, a height h of about 10 μm, and a width w corresponding to the bottom of the triangle of about 20 μm. A plurality of triangular ridges 21 are formed in parallel at intervals of about 20 μm. The thickness d of the base portion 20b of the sheet 20 is about 40 μm.

  Next, as shown in FIG. 2B, the substrate 30 is sucked and placed on the surface of the upper mold 10b on the lower mold 10b side by suction from the first suction port 13 of the upper mold 10b. Step 2) in FIG. An LED chip 31 is mounted on the substrate 30, and the substrate 30 is adsorbed so that the LED chip 31 is positioned on the central axis 11 b of the recess 11 of the lower mold 10 a.

  Then, as shown in FIG. 2C, the sheet 20 is sucked from the suction port 12 of the lower mold 10a and adsorbed on the surface of the lower mold 10a on the upper mold 10b side by negative pressure (Step 3 in FIG. 1). ). The sheet 20 is in close contact with the lower mold 10a along the sealing member-equipped surface 11a of the recess 11 of the lower mold 10a.

  Thereafter, as shown in FIG. 2D, the resin material 40 is injected onto the sheet 20 in the recess 11 (step 4 in FIG. 1). The resin material 40 is made of colorless and transparent silicone, and is in a molten state at a high temperature.

  Next, as shown in FIG. 2E, the upper die 10b is lowered to the lower die 10a side, and the LED chip 31 is embedded in the resin material 40 (step 5 in FIG. 1). At this time, the O-ring 15 comes into contact with the lower mold 10a, and the space between the upper mold 10b and the lower mold 10a surrounded by the O-ring 15 is in an airtight state. And it attracts | sucks from the 2nd suction port 13 of the upper metal mold | die 10b, and the space between the upper metal mold | die 10b and the lower metal mold | die 10a is made into a vacuum state (step 6 in FIG. 1). As a result, the resin material 40 reaches the gap between the resin material 40 and the LED chip 31, or the resin material 40 and the LED chip 31 are in close contact with each other. And it cools in this state, the resin material 40 is solidified, the sealing member 41 is formed, and the metal mold | die 10 and the sheet | seat 20 are removed (step 6 in FIG. 1). Thereby, the LED lamp 50 is manufactured.

  FIG. 4 shows an enlarged partial cross-sectional view of the surface of the sealing member 41 of the LED lamp 50. As shown in FIG. 4, the surface 41 a of the sealing member 41 has a fine uneven shape by transferring the fine unevenness of the upper surface 20 a of the sheet 20. As a result, the light of the LED chip 31 that has reached the surface 41a of the sealing member 41 is prevented from being totally reflected by the surface 41a and is emitted to the outside (see symbol P in FIG. 4). Thus, the LED lamp 50 manufactured by the manufacturing method 1 improves the light extraction efficiency.

  According to the manufacturing method 1 of the present embodiment, since the sheet 20 interposed between the mold 10 and the sealing member 41 has fine unevenness, the shape of the fine unevenness is excellent on the surface of the sealing member 41. The fine irregularities can be formed on the surface 41 a of the sealing member 41 by being transferred. In addition, since the sheet 20 also functions as a release sheet, the mold 10 and the sealing member 41 have a good releasability, and fine irregularities are favorably formed on the surface 41 a of the sealing member 41. In addition, since the sheet 20 can be used instead of the release sheet used in the conventional compression molding, the number of steps is not changed from that in the conventional compression molding, and the production efficiency is not lowered.

  In addition, since the molding surface 11a with the sealing member of the lower mold 10a is not provided with fine irregularities and the sheet 20 has fine irregularities, the sheet 20 can be obtained by simply replacing the sheet 20 with a sheet having desired fine irregularities. The fine irregularities can be formed on the surface 41a of the sealing member 41, and it is easy to change the fine irregularities. Furthermore, the versatility of the mold 10 is increased, which is advantageous in terms of cost.

  FIG. 5 shows a flow chart of an LED lamp manufacturing method 100 according to another embodiment of the present invention, and FIGS. 6 and 7 are diagrams for explaining the manufacturing method 100. In addition, the same code | symbol is attached | subjected to the process same as the manufacturing method 1 of an LED lamp, and an equivalent member, and the description is abbreviate | omitted. First, as shown in FIGS. 6A ′ to E ′, the first sealing layer 401 is formed by the same process as Step 1 to Step 6 of the manufacturing method 1. However, the first lower mold 100a is used instead of the lower mold 10a. As shown in FIG. 6A, since the first lower mold 100a has a rectangular parallelepiped recess 110 larger than the outer shape of the LED chip 31, the first sealing layer 401 is a rectangular parallelepiped. The sealing resin 400 forming the first sealing layer 401 is made of colorless and transparent silicone. After step 6 (see FIG. 1), as shown in FIG. 6F ′, the first lower mold 100a and the sheet 20 are removed with the substrate 30 adsorbed to the upper mold 10b (see FIG. 5). Step 7 ').

Next, as shown in FIG. 7G, a second lower mold 101a is prepared (step 8 in FIG. 5). The second lower mold 101 a includes a hemispherical recess 111 that is larger than the outer shape of the first sealing layer 401.
Then, as shown in FIG. 7H, the sheet 200 is sucked from the suction port 12 of the second lower mold 101a and brought into close contact with the recess 111 of the second lower mold 101a by the negative pressure (step in FIG. 5). 9). The sheet 200 is a thin film made of ETFE, and the surface thereof is a smooth surface.

Thereafter, as shown in FIG. 7I, a resin material 402 is injected onto the sheet 200 in the recess 111 (step 10 in FIG. 5). The resin material 402 is made of colorless and transparent epoxy.
Then, as shown in FIG. 7J, the upper mold 10b is lowered to the second lower mold 101a side, and the first sealing layer 401 is embedded in the resin material 402 (step 11 in FIG. 5). ). The space between the upper mold 10b and the lower mold 101a is evacuated by suction from the second suction port 113 of the upper mold 10b (step 12 in FIG. 5). Thereafter, as shown in FIG. 7K, the resin material 403 is solidified to form the second sealing layer 403, and the upper mold 10b, the second lower mold 101a, and the sheet 200 are removed (step in FIG. 5). 13). Thereby, the LED lamp 500 is manufactured.

  FIG. 8 shows an enlarged partial cross-sectional view of the first sealing layer 401 and the second sealing layer 403 of the LED lamp 500. Since the first sealing layer 401 is made of silicone and the second sealing layer 402 is made of epoxy, the refractive index of the first sealing layer 401 located on the inner side is higher than that on the outer side. It is smaller than the refractive index of the second sealing layer 403. The fine unevenness of the upper surface 20a of the sheet 20 is transferred to the interface 401a between the first sealing layer 401 and the second sealing layer 403 having such a refractive index relationship, and the interface 401a becomes a fine uneven surface. ing. As a result, the light from the LED chip 31 is scattered from the first sealing layer 401 to the second sealing layer 403 side at the interface 401 a between the first sealing layer 401 and the second sealing layer 403. The mixing of the light from the LED chip 31 is promoted, and the luminance balance is improved. (See symbol Q in FIG. 8).

  9A and 9B show LED lamps 500a and 500b, which are modifications of the LED lamp 500 manufactured by the manufacturing method 100, respectively. The LED lamp 500a shown in FIG. 9A is formed by the same method as the manufacturing method 100, but uses a sheet 200 that does not have fine irregularities in place of the sheet 20 used when forming the first sealing layer 401. Then, the sheet 20 having fine irregularities is used instead of the sheet 200 used when forming the second sealing layer 403. As a result, as shown in FIG. 9A, in the LED lamp 500a, the interface 401b between the first sealing layer 401 and the second sealing layer 403 is a flat surface having no fine unevenness, and the second sealing The surface 403b of the layer 403 has fine unevenness. Thereby, the light of the LED chip 31 that has reached the surface 403b of the second sealing layer 403 is prevented from being totally reflected by the surface 403b, and thus the light extraction efficiency is improved.

  On the other hand, the LED lamp 500b shown in FIG. 9B is formed by the same method as the manufacturing method 100, but uses the sheet 20 having fine irregularities instead of the sheet 200 used when forming the second sealing layer 403. To do. Accordingly, as shown in FIG. 9B, in the LED lamp 500b, the interface 401a between the first sealing layer 401 and the second sealing layer 403 and the surface 403b of the second sealing layer 403 both have fine irregularities. It will be. As a result, the light from the LED chip 31 is dispersed at the interface 401a, and total reflection is prevented at the surface 403b. Therefore, the luminance balance is improved and the light extraction efficiency is improved.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 1,100 Manufacturing method 10 Mold 10a, 100a, 101a Lower mold 10b Upper mold 11, 110, 111 Recessed part 11a, 110a, 111a Shaped surface with sealing member 12 Suction port 13 First suction port 14 Second suction Port 15 O-ring 20, 200 Sheet 21 Triangular protrusion 30 Substrate 31 LED chip 40, 400, 402 Resin material 41 Sealing member 401 First sealing layer 401 a, 402 b Interface 403 Second sealing layer 403 a, 403 b Surface 50, 500 LED lamp

Claims (4)

A method of forming fine irregularities on the surface of a sealing member surrounding an LED chip,
When molding the sealing member, a sheet having fine irregularities is interposed between the molding member-equipped surface of the mold and the sealing member, and the fine irregularities of the sheet are formed on the surface of the sealing member. A method of forming fine irregularities on the surface of a sealing member, characterized in that:   The method according to claim 1, wherein the sheet is adsorbed by a negative pressure to the molding member-equipped surface of the mold.   A method for manufacturing an LED lamp, comprising the method according to claim 1.   An LED lamp manufacturing method in which the LED chip is sequentially surrounded by a first sealing member and a second sealing member, the surface of the first sealing member and / or the second sealing member. A method for producing an LED lamp, wherein fine irregularities are formed on the surface of the substrate by the method according to claim 1.

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