JP2002335020A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stable light emitting device wherein change of size is easy and strength is high to the stress from the outside. SOLUTION: This light emitting device is equipped with a substrate 2 having an upper surface and a lower surface, a light emitting element 1 arranged on the upper surface of the substrate, and a sealing member 5 covering at least a part of the light emitting element. The substrate has a through hole 9 having apertures on the upper surface and the lower surface. At least the aperture of the upper surface of the through hole is formed separately from an end portion of the substrate. The sealing member is formed continuously to reach the lower surface of the substrate from at least the side surface of the light emitting element, via the through hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device whose size can be easily changed and which is stable against external force.
An object of the present invention is to provide a light-emitting device in which light emitted from a side surface of a light-emitting element can be stably and efficiently emitted from an upper surface to improve luminous efficiency.

[0002]

2. Description of the Related Art Chip type light emitting diodes (hereinafter, referred to as LED)
As shown in FIG. 11, a light emitting device is die-bonded with a resin or the like to a concave portion of a resin package in which lead electrodes are embedded. FIG.
1 is mounted face down, and in this case, the electrode of the light emitting element and the lead electrode are bonded with a conductive die bond material. In the case of face-up mounting, the lead electrode and each electrode of the light emitting element are electrically connected by a wire or the like. Further, a translucent mold resin is sealed in the concave portion of the resin package so as to protect the light emitting element. Since the recess is formed in the package, it flows before the mold resin cures,
D elements and wires can be easily sealed without being exposed. Resins that do not cure after encapsulation can be used if they are covered with, for example, glass.

Further, the resin package does not need to have a concave portion, and may be a flat substrate made of a resin provided with lead electrodes as shown in FIG. By arranging the light emitting element on this substrate and covering it with a translucent resin,
It can be a chip type LED. In this case, since there is no concave portion, the molding resin can be easily molded by molding with a mold or by potting a resin having high viscosity and curing with light or heat.

However, when the resin package having the concave portion is used as described above, it is easy to enclose the resin, but the size of the resin package becomes the size of the LED, so that it is not easy to change the size. . In particular, when the size of the resin package is reduced, it becomes difficult to control the shape. For example, when the angle of the wall surface of the concave portion changes, the directivity of light also changes. FIG.
In the case of using a flat substrate having no concave portion as in 2, the size can be easily changed. However, since there is no wall for protecting the mold resin as compared with the case where the concave portion is provided, the substrate is weak against external stress. There is a problem that the mold resin is easily peeled off.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned problems, and provides a stable light emitting device which can be easily changed in size and has high strength against external stress.

[0006]

In order to solve the above-mentioned problems, the present invention provides a substrate having an upper surface and a lower surface, a light emitting element disposed on the upper surface of the substrate, and covering at least a part of the light emitting element. A light-emitting device comprising:
The substrate has a through hole having openings on the upper and lower surfaces,
The through hole is formed such that at least an opening on the upper surface is formed away from an end of the substrate, and the sealing member is provided continuously from at least a side surface of the light emitting element to the lower surface of the substrate via the through hole. It is characterized by. With such a structure, it is possible to provide a light-emitting device in which the size can be easily changed and the sealing member does not easily peel off.

In the light emitting device of the present invention, a sealing member including a light reflecting member for reflecting light from the light emitting element can be used. Thus, light can be prevented from being emitted from the side surface of the light emitting element, and light emission luminance from the front (upper surface) is improved.

In the light-emitting device of the present invention, a sealing member made of a light-transmitting member that transmits light from the light-emitting element can be used. When a light-transmitting member is used, the upper surface of the light-emitting element can be used. Through the through-hole to reach the lower surface of the substrate. Thereby, the light emitting element can be more firmly fixed to the substrate.

Further, in the light emitting device of the present invention, the sealing member may include a light reflecting member and a light transmitting member, and the light reflecting member may be provided on at least a side surface of the light emitting element. Accordingly, it is possible to efficiently prevent light from being emitted from the side surface of the light emitting element and to strengthen the adhesive force with the substrate.

Further, in the light emitting device of the present invention, the opening of the through hole on the upper surface of the substrate is formed between the end of the substrate and the element installation portion where the light emitting element is provided. Thereby, the sealing member can be easily injected into the through hole.

Further, the light emitting device of the present invention has a conductive member continuous from the upper surface to the lower surface of the substrate, and the conductive member is formed continuously from the upper surface to the lower surface of the substrate via a through hole. Thereby, a light emitting device in which the conductive member is not exposed on the side surface can be obtained.

Further, in the light emitting device of the present invention, the light emitting element may be arranged on the conductive member. Thereby, conduction can be achieved without using a wire.

Further, as the light reflecting member of the present invention, a member containing at least one selected from the group consisting of silicon oxide, barium titanate, titanium oxide and aluminum oxide can be used.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a light emitting device according to an embodiment of the present invention will be described with reference to the drawings. The light emitting device according to the embodiment of the present invention has a through hole in a substrate as shown in FIG. 1, and a sealing member covering at least a part of a light emitting element reaches from a side surface of the element to a lower surface of the substrate. It is provided continuously. As described above, by providing the sealing member having a function of protecting the light emitting element and fixing the light emitting element to the substrate so as to be continuous not only on the upper surface of the substrate but also in the through hole, the contact area with the substrate is increased. Therefore, the adhesive strength between the light emitting element and the sealing member and the substrate is improved, and the sealing member, the light emitting element, and the like can be prevented from being peeled off by an external force. By allowing the sealing member that has reached the lower surface to expand in the horizontal direction, the resin is further stably fixed to the substrate. By using the through-holes and the sealing member in this manner, it is possible to obtain a light emitting device in which the sealing member is not easily peeled off without using a resin package having a side wall as shown in FIG. Further, since the side wall does not need to be formed, the size of the substrate can be easily changed, and a light emitting device having a shape and a size suitable for the purpose can be obtained.

(Through Hole) The through hole formed in the substrate is formed so as to have openings on the upper surface and the lower surface of the substrate on which the light emitting element is installed, and the opening on the upper surface is provided with the light emitting element. It is formed so as to be between the position and the end face of the substrate. In FIG. 1, the through hole has the same shape from the upper surface to the lower surface, and is formed substantially directly below. Such a shape is preferable because it is easy to form. However, the present invention is not limited to such a shape, and the shape of the opening, the angle of the side surface, and the like need not be particularly limited, and may be inclined, for example, as shown in FIG. Further, when the sealing member is formed so as to become larger as approaching the lower surface as shown in FIG. 10, the sealing member becomes caught on the substrate when it is cured, so that the sealing member is more stable and hardly peels off. Moreover, with such a shape, the sealing resin does not have to reach the lower surface of the substrate, and a strong adhesive force can be efficiently obtained with a small amount of the sealing member. Further, the opening on the upper surface of the through-hole may be separated from the side surface of the substrate. The opening on the lower surface may be formed only on the lower surface of the substrate, or may extend to the side surface.

Since the opening on the upper surface of the through hole is formed between the position where the light emitting element is arranged and the end face of the substrate, the sealing member is easily filled after the light emitting element is mounted. Further, as shown in FIG. 6, the light-emitting element can be provided at a position where the light-emitting element is arranged. In this case, however, it is necessary to make the opening smaller than the light-emitting element. In order to provide them, it is necessary to consider a forming method such as providing a sealing member in advance and mounting a light emitting element thereon.

The number of the through holes may be only one, or two or more. When only one light emitting element is provided, the light emitting element may be provided at a position where the light emitting element is arranged as shown in FIG.
Alternatively, as shown in FIG. 9, it may be provided between the position where the light emitting element is arranged and the end face of the substrate. Even with only one light-emitting element, the effect of preventing the light-emitting element and the sealing member covering the light-emitting element from peeling off from the substrate can be obtained. In addition, when providing a plurality,
When a conductive member to be described later is continuous from the upper surface to the lower surface via the through hole, it is preferable to use separate through holes because a short circuit between the electrodes can be prevented. In the case of providing a plurality, it is easy to form each of them in the same shape, but there is no problem even if the shapes are different. Further, it may be formed at a position where the pair is left-right symmetric or vertically symmetrical, or may be formed at an arbitrary position. As a forming method, it can be opened using a drill or can be provided by a laser. Further, it can also be formed by punching.

(Substrate) As the substrate provided with the through hole, any material can be used as long as it is a material which is easy to process and has durability. As a specific material of such a substrate, various materials such as a glass epoxy resin in which a conductive member described later is formed on the upper surface and the lower surface in advance, or copper, aluminum, various alloys, and ceramics can be used. If a conductive material is used, S
After forming an insulating film such as iO ₂ or SiN _x, copper, gold, an alloy containing a thin film pattern and these metals such as silver, preferably utilized to what was formed by CVD or sputtering, such as a multilayer film including these metals Can be.

(Sealing Member) The sealing member covering at least a part of the light emitting element protects the light emitting element,
It also has a function as an adhesive for fixing the light emitting element to the substrate. Although the light emitting element and the substrate can be adhered to each other with only the die bonding agent, if stronger adhesiveness is required, the adhesiveness can be improved by providing a sealing member to cover the light emitting element and its periphery. Can be. However, the larger the volume, the easier it is to apply an external force. Therefore, as shown in FIG. 12, if it is formed so as to be in contact with only the upper surface of the substrate, it is easier to peel off. By being formed so as to be continuous, the area in contact with the substrate is increased, and furthermore, since the contact can be made three-dimensionally, a strong adhesive force can be obtained.

As the material used as the sealing member, a material including a light reflecting member for reflecting light from the light emitting element or a light transmitting member capable of transmitting light can be used. For example, a curable resin can be used. When a sealing member including a light reflecting member is used, the sealing member may not be provided on the upper surface of the light emitting element, and may be provided so as to be continuous from the side surface of the element to the through hole. By providing the sealing member including the light reflecting member on the side surface of the light emitting element, light can be emitted only from the top surface of the light emitting element. Since the resin used as the sealing member may be easily deteriorated depending on the wavelength of light emitted from the light-emitting element, the deterioration can be suppressed by using the sealing member including the light reflecting member only on the side surface. . When the resin is deteriorated and colored, the light is absorbed, and the light emission efficiency is reduced. However, such a problem can be avoided by suppressing the deterioration.

In the case where a sealing member including a light reflecting member is used, light can be prevented from being emitted to the substrate side by providing the sealing member not only on the side surface but also on the bottom surface of the light emitting element.
A die bonding material is provided between the substrate and the light emitting element. If there is a gap, it is preferable to provide a light reflecting member so as to fill the gap. Since the distance between the bottom surface of the light emitting element and the substrate is short, when light is emitted from the bottom of the light emitting element, the resin is likely to be repeatedly reflected and the resin is likely to deteriorate. Such deterioration can be prevented. In this case, the sealing member including the light reflecting member is provided so as to be continuous from the side surface of the light emitting element, and further provided so as to be continuous to the through-hole, thereby having adhesiveness to the substrate and improving light extraction efficiency. be able to. Further, even if the light emitting element is provided so as to be continuous from the bottom to the through hole, the light extraction efficiency can be improved.

As the light reflecting member, it is preferable to use at least one selected from the group consisting of silicon oxide, barium titanate, titanium oxide and aluminum oxide.
Particles made of these members can be used as a light reflecting member mixed in a sealing member.

When a light-transmitting member is used, it can be provided continuously from the upper surface of the light emitting element to the through hole, so that a stronger adhesive force can be obtained. Then, using a sealing member having both the light reflecting member and the light transmitting member as described above, for example, as shown in FIGS. The member may be formed so as to reach the through hole from the upper surface of the light emitting element. Further, as shown in FIG. 5, a sealing member including a light reflecting member may be provided so as to reach the through hole from the side surface of the light emitting element, and a light transmitting member may be formed on the upper surface of the light emitting element. As described above, the through-hole may be filled with a light-transmissive member or a light-reflective member. If the light-emitting element is provided continuously from at least the side surface, the effect of improving the adhesive strength is obtained. Is obtained.

When a translucent member is used, a light diffusing material for diffusing light may be mixed. Thereby, light dispersibility is improved and a uniform light emitting device can be obtained. Alternatively, a fluorescent substance which can be excited by light from the light emitting element and emit light having a wavelength longer than that wavelength may be mixed. Accordingly, mixed color light of light from the light emitting element and light from the fluorescent substance can be emitted, so that a light emitting device having various emission wavelengths can be obtained.

It is preferable that the sealing member is provided so as to completely fill the inside of the through hole. In particular, it is more preferable to reach the lower surface of the substrate, because the bonding area becomes larger. However, it is only necessary that the light emitting element is continuous from at least the side surface to the through hole. Even when the light emitting element is continuous to the lower surface, the light emitting element may be formed so as to be continuous through a part of the side surface of the through hole. Such a sealing member can be provided by potting, or can be provided by a method such as printing and coating after protecting the upper surface of the light emitting element with a mask or the like.

(Conductive Member) The conductive member is provided on the substrate so as to conduct with the element electrode provided on the light emitting element. The conductive member is provided on the substrate from the upper surface (the surface on which the light emitting element is arranged). It is provided so as to be continuous up to the lower surface. FIG.
And may be provided so as to be exposed on the side surface (end surface) of the substrate, or may be provided via a through hole as shown in FIG. In the case where the light emitting element is provided via the through hole, the light emitting element may be provided on all the openings of the through hole as shown in FIG. 1 or only on the side where the light emitting element is arranged as shown in FIG. If it is provided at the position where the light emitting element is arranged, it can be mounted face down. Further, as shown in FIG. 7, it is possible not to provide the light emitting element at the position where the light emitting element is arranged. In this case, since the distance between the electrodes can be increased, a short circuit can be prevented, and the face-up can be prevented. It can be used when mounting with. In such a case, both the positive and negative electrodes may be provided in the same through-hole, but it is preferable to form them through different through-holes because short-circuiting is likely to occur. In addition, the position is further reduced by short-circuiting through the through holes formed apart from each other.

When the conductive member is provided through the through hole, it is preferable that the sealing member is formed on the conductive member. Even if the sealing member is not directly in contact with the through hole, that is, the substrate material, if the sealing member is provided continuously from the side surface of the light emitting element to the through hole, the adhesion area with the substrate (the substrate via the conductive member) is reduced. It's still going to grow.

As a material used for the conductive member, a high heat conductive material is preferable in order to efficiently extract heat from the light emitting element to the outside, and Au, Cu, Al, an alloy thereof, or the like can be suitably used. In particular, copper and aluminum can be suitably used because of ease of processing. Further, plating with a metal or alloy having high reflectivity can also be performed. Gold, silver, copper, nickel and various alloys can be suitably used as such a metal.

(Light Emitting Element) As the light emitting element used in the present invention, various semiconductor light emitting elements can be used. As a specific semiconductor light emitting device, a device in which an n-type nitride semiconductor and a p-type nitride semiconductor are stacked on a substrate of sapphire, SiC, spinel, GaN, or the like using MOCVD or the like is preferably used. it can. GaN, GaAl
N, InGaN, AlN, InN, InGaAlN, G
InGaP, as well as nitride semiconductors such as aInBN
GaP, GaAs, GaAlAs, AlP, AlAs,
A light-emitting element using various semiconductors such as ZnS, ZnSe, and SiC for a light-emitting layer can be suitably used. When a conductive material is used for the substrate, the support member may be die-bonded with an Ag paste, solder, or the like so as to be electrically connected, or an insulating layer may be interposed therebetween.

Hereinafter, specific embodiments of the present invention will be described in detail, but it is needless to say that the present invention is not limited to these embodiments.

[0031]

(Embodiment 1) A flat plate made of glass epoxy resin is used as a substrate. A copper thin film as a conductive member is formed on the upper and lower surfaces of the substrate by bonding or laminating. Next, a film is applied to the substrate with a root applied thereto, and the film is exposed and removed by chemical etching or the like, thereby forming a copper thin film pattern as shown by a hatched portion in FIG. Using a drill, etching, laser, or the like, a plurality of through holes are formed on the copper thin film forming substrate in the X direction and the Y direction as shown in FIG. Next, as shown in the cross-sectional view of FIG. 13C, the copper thin film is formed through the through holes so as to be continuous from the upper surface to the lower surface through the through holes. Thereby, the through holes arranged in the X direction are provided so as to be continuous, but the through holes arranged in the Y direction are
As shown in (c), a copper thin film is formed such that the substrate is exposed on the upper surface and the lower surface apart from each other. That is, the copper thin films of the four through holes arranged in the X direction are continuous, and the copper thin films of the two through holes arranged in the Y direction are formed so as not to be in contact with each other.

Next, as shown in FIG. 13D, the light emitting elements are arranged between the through holes arranged in the Y direction and in contact with both the copper thin films formed separately. At this time, 1
The positive and negative electrodes of the two light emitting elements are arranged so as to be in contact with the copper thin films formed separately from each other. Solder is previously formed on a copper thin film, and is adhered thereon.

Next, a resin containing TiO ₂ is potted on the through hole as a light reflecting member as shown in FIG. At this time, it is necessary to control the amount of the resin so that the TiO ₂ -containing resin does not cover the upper surface of the light emitting element. Ti
After curing the O ₂ containing resin, a translucent resin is coated on the entire surface of the substrate, it is cured. After curing, the substrate is cut along the broken line in FIG. 13 (f) to obtain the light emitting device of the present invention as shown in FIG. 13 (g). This cutting position can be changed arbitrarily.

[0034]

According to the present invention, a through hole is provided in a substrate on which a light emitting element is arranged, and a sealing member is continuously provided from the side surface of the light emitting element to the inside of the through hole, so that the adhesive force between the substrate and the sealing member is reduced. Can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a light emitting device of the present invention.

FIG. 2 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 3 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 4 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 5 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 6 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 7 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 8 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 9 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 10 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 11 is a schematic cross-sectional view showing a light emitting device shown for comparison with the present invention.

FIG. 12 is a schematic sectional view showing another light emitting device shown for comparison with the present invention.

FIG. 13 is a process chart showing a step of forming the light emitting device of the present invention. (A) Schematic diagram of a substrate on which a conductive member is formed. (B) Schematic diagram of a substrate on which a through hole is formed. (C) Cross-sectional diagram of FIG. 13B. (D) Schematic diagram of a substrate on which a light emitting element is arranged. (E) Sectional view of FIG. 13 (d) (f) Schematic view of substrate on which light reflecting member is formed (g) Sectional view of FIG. 13 (f)

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light-emitting element 2 ... Substrate 3 ... Conductive member 4 ... Die bonding material 5 ... Sealing member (containing a light reflecting member) 6 ... Sealing member (light transmitting) 7 ... wire 8 ... resin package 9 ... through hole

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[Procedure amendment]

[Submission date] May 24, 2001 (2001.5.2)
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

[0031]

(Embodiment 1) A flat plate made of glass epoxy resin is used as a substrate. A copper thin film as a conductive member is formed on the upper and lower surfaces of the substrate by bonding or laminating. Next, a negative film is attached to the substrate, exposed, and removed by chemical etching or the like, thereby forming a copper thin film pattern as shown by a hatched portion in FIG. Using a drill, etching, laser, or the like, a plurality of through holes are formed on the copper thin film forming substrate in the X direction and the Y direction as shown in FIG. Next, as shown in the cross-sectional view of FIG. 13C, the copper thin film is formed through the through holes so as to be continuous from the upper surface to the lower surface through the through holes. Thereby, the through holes arranged in the X direction are provided so as to be continuous, but the through holes arranged in the Y direction are
As shown in (c), a copper thin film is formed such that the substrate is exposed on the upper surface and the lower surface apart from each other. That is, the copper thin films of the four through holes arranged in the X direction are continuous, and the copper thin films of the two through holes arranged in the Y direction are formed so as not to be in contact with each other.

Continued on front page F-term (reference) 4M109 AA01 AA02 BA03 DB15 DB16 EB18 EC11 EC12 GA01 5F041 CA40 CA46 DA02 DA04 DA07 DA09 DA12 DA20 DA43 DA46 DA57 DB09

Claims (9)

[Claims] 1. A light emitting device comprising: a substrate having an upper surface and a lower surface; a light emitting element disposed on the upper surface of the substrate; and a sealing member covering at least a part of the light emitting element. The substrate has a through-hole having an opening on an upper surface and a lower surface, and the through-hole is formed such that at least an opening on the upper surface is separated from an end of the substrate, and the sealing member is at least a side surface of the light emitting element. A light-emitting device which is provided continuously from the lower surface of the substrate through the through hole. 2. The light emitting device according to claim 1, wherein the sealing member includes a light reflecting member that reflects light from the light emitting element. 3. The light emitting device according to claim 1, wherein the sealing member is made of a light transmitting member that transmits light from the light emitting element. 4. The light emitting device according to claim 3, wherein the translucent member is provided continuously from the upper surface of the light emitting element to the lower surface of the substrate via the through hole. 5. The light emitting device according to claim 1, wherein the sealing member includes a light reflecting member and a light transmitting member, and the light reflecting member is provided on at least a side surface of the light emitting element. 6. The light emitting device according to claim 1, wherein the through hole has an opening on the upper surface of the substrate formed between an end of the substrate and an element installation portion on which the light emitting element is provided. apparatus. 7. The substrate has a conductive member continuous from the upper surface to the lower surface, and the conductive member is formed continuously from the upper surface to the lower surface of the substrate via the through hole. Or the light emitting device according to claim 6. 8. The light emitting device according to claim 1, wherein said light emitting element is disposed on said conductive member. 9. The light emitting device according to claim 1, wherein the light reflecting member includes at least one selected from the group consisting of silicon oxide, barium titanate, titanium oxide, and aluminum oxide.