JP2008053571A - Light emitting device and planar light emitting device using the same - Google Patents

Abstract

An object of the present invention is to provide a thinner light-emitting device by reducing torsional stress and warpage received from a substrate, thereby preventing peeling of a sealing resin and electrical disconnection.
A rectangular first substrate 101, a plurality of light emitting elements 103 arranged in a longitudinal direction of the upper surface of the first substrate 101, and a plurality of convex seals covering the plurality of light emitting elements 103. A stop resin 105 and a lower surface of the first substrate 101, which is disposed in a portion corresponding to the convex sealing resin 105, and is longer than the convex sealing resin 105. A plurality of second substrates 107 which are long in the direction and whose end portions are located between the convex sealing resin 105 and another convex sealing resin 105.
[Selection] Figure 1

Description

  The present invention relates to a light emitting device and a planar light emitting device using the same.

  Patent Document 1 discloses a technique in which a plurality of light emitting elements are arranged in the longitudinal direction of a rectangular mounting substrate as a light emitting device, and the plurality of light emitting elements are individually sealed with a sealing resin. .

Japanese Utility Model Publication No. 05-38627.

  However, in this configuration, when the mounting board is twisted, the entire board is subjected to torsional stress, and a physical force is applied to the light emitting element, causing problems such as peeling from the mounting board and electrical disconnection. . Furthermore, problems such as peeling of the sealing resin also occur.

  In order to solve the above problems, a light-emitting device according to the present invention includes a rectangular first substrate, a plurality of light-emitting elements arranged in the longitudinal direction of the upper surface of the first substrate, and the plurality of light-emitting elements. A plurality of convex sealing resins covering the first substrate, the first substrate being disposed on a lower surface of the first substrate corresponding to the convex sealing resin, and the first substrate more than the convex sealing resin A plurality of second substrates that are long in the longitudinal direction and whose end portions are located between the convex sealing resin and another convex sealing resin.

  As a result, the first substrate on which the second substrate is arranged has a higher physical strength, and thus is less likely to be deformed than a portion that does not have the second substrate. That is, the portion that does not have the second substrate has a low physical strength and is easily deformed. Then, when a twisting force is applied to the light emitting device, the portion without the second substrate is preferentially twisted. Furthermore, even if a torsional stress is applied to the convex sealing resin by making the second substrate longer than the convex sealing resin in the longitudinal direction of the first substrate, no stress is applied to the convex sealing resin. . Since the portion having the convex sealing resin is not twisted, the problem of peeling of the sealing resin can be solved. Further, since the portion having the light emitting element is not twisted, the problem of peeling of the light emitting element from the mounting substrate and electrical disconnection can be solved.

  In addition, since the second substrate is partially formed and arranged with respect to the first substrate, stress generated at the interface can be reduced, so that problems such as warping do not occur.

  In the light emitting device according to the present invention, a space between the adjacent convex sealing resins has a flat sealing resin.

  As a result, the physical strength of the portion that does not have the second substrate is improved, so that the occurrence of twist itself can be prevented. With the flat sealing resin, light from the light emitting element can be guided at this portion. Accordingly, when a planar light emitting device is optically connected to the light guide plate, it is possible to suppress the occurrence of a fire phenomenon. Thereby, the effective light emitting part of the light guide plate can be enlarged.

  Furthermore, since the bonding area with the first substrate is increased by the flat sealing resin, the adhesion between the sealing resin and the first substrate is improved, and the problem of peeling of the sealing resin is further reduced. Is possible.

  The light emitting device according to the present invention has a semi-cylindrical shape in which the convex sealing resin extends in the short direction.

  As a result, the thickness can be further reduced, and the problem of twist becomes more conspicuous as the thickness is reduced. Therefore, the present invention is more effective.

In the light emitting device according to the present invention, a phosphor layer is arranged for each of the plurality of light emitting elements.
Here, in the present specification, the phosphor layer includes at least phosphor powder and a translucent resin, and those containing a diffusing material.

The phosphor layer exhibits a bonding capability with respect to the first substrate at the portion of the translucent resin that is the resin portion, and the phosphor powder portion does not exhibit the bonding capability. Therefore, by having the phosphor layer, the adhesion with the first substrate is weakened, and the twisting problem becomes remarkable, so that the configuration of the present application becomes more effective.
Further, the chromaticity unevenness generated in each phosphor layer is also averaged by the flat sealing resin, and the occurrence of chromaticity unevenness can be suppressed.

  In the light emitting device according to the present invention, the plurality of light emitting elements have different wavelengths. Even for light emitting elements having different wavelengths, color mixing is promoted by the flat sealing resin. When used in a planar light emitting device, chromaticity unevenness hardly occurs and the effective light emitting area of the light guide plate can be increased.

  Moreover, the planar light-emitting device concerning this invention is equipped with the light-guide plate which has a light-incidence part, and the light-emitting device of any one of Claims 1 thru | or 5 optically connected to this light-guide plate. It is characterized by.

  In the planar light emitting device according to the present invention, the light incident portion of the light guide plate has a concave portion, and the concave portion and the sealing resin are engaged with each other. Thereby, alignment of a light-emitting device and a light-guide plate becomes easy.

  Furthermore, in the planar light emitting device according to the present invention, the concave portion has a semi-cylindrical shape. As a result, optical loss can be reduced.

  According to the present invention, even if the mounting substrate is twisted, the light emitting device is prevented from being damaged by twisting only an arbitrary portion. Furthermore, the light-emitting device is prevented from being damaged by preventing twisting.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below illustrates the light emitting device and the planar light emitting device for embodying the technical idea of the present invention, and the present invention limits the light emitting device and the planar light emitting device to the following. is not. Further, the size and positional relationship of the members shown in the drawings are exaggerated for clarity of explanation.

<First Embodiment>
1 to 4 show a light-emitting device according to the first embodiment. (A) is a front view and (b) shows a corresponding perspective view. (A) is shown in a state where the light-transmitting part is seen through, and the internal structure of the light-emitting element and the like is clarified. (B) shows the translucent part in an opaque state to clarify the outer shape of the light emitting device.

  Reference numeral 101 denotes a rectangular first substrate. Reference numeral 103 denotes a plurality of light emitting elements arranged in the longitudinal direction on the first substrate. Reference numeral 105 denotes a plurality of convex sealing resins covering the plurality of light emitting elements. Reference numeral 107 denotes a plurality of second substrates disposed below the first substrate and corresponding to the convex sealing resin. The second substrate is longer than the convex sealing resin than the longitudinal direction of the first substrate.

  The longitudinal direction of the rectangular first substrate is the x direction, the short direction is the z direction, and the thickness direction is the y direction. As described above, since the longitudinal direction of the rectangular first substrate is defined as the x direction, the entire light emitting device has a configuration extending in the x direction. Therefore, torsional stress is likely to occur on the yz plane formed by the y-axis and the z-axis. When twisting stress is applied to the light-emitting device, the light-emitting element is peeled off, electrically disconnected, or mechanically broken, but the part reinforced by partial reinforcement with the second substrate is A portion that is not deformed and not reinforced is preferentially twisted. By removing the preferentially twisted portion from the mounting portion of the light emitting element, it is possible to reduce adverse effects on the light emitting element.

  Furthermore, by having a plurality of light emitting elements in one light emitting device, when applied to a planar light emitting device, a plurality of light emitting devices are not necessary, and there is no need to consider mounting misalignment between the light emitting devices.

  1, 2, 3, and 4 are variations of the convex sealing resin. Arbitrary light distribution characteristics can be obtained by changing the shape of the sealing resin. Each shows (a) a front view and (b) a corresponding perspective view. A symmetrical convex sealing resin as shown in FIGS. 1 to 3 may be arranged, or an asymmetric convex sealing resin may be arranged as shown in FIG. When a planar light emitting device is optically connected to the light guide plate using an asymmetric convex sealing resin, the light incident on the side of the light guide plate is emitted to the outside of the light guide plate, resulting in an optical loss. Can be prevented.

Below, each structural member is described.
(First substrate)
As a structure of the first substrate, it is only necessary that the mounting surface has a rectangular shape and an electrode capable of supplying electricity to the light emitting element to be mounted. Examples of the substrate include a ceramic substrate, a glass epoxy substrate, an aluminum base substrate, a copper base substrate, a printed substrate, and a flexible substrate.

(Light emitting element)
A light-emitting element is a device in which a semiconductor such as GaAlN, ZnO, ZnSe, SiC, GaP, GaAlAs, AlN, InN, AlInGaP, InGaN, GaN, or AlInGaN is formed on a substrate as a light-emitting layer.

(Convex sealing resin)
As the translucent resin, silicone resin, epoxy resin, acrylic resin, or the like is used. Preferably, gelled silicone is used. This is because there is little deterioration and the wire can be protected from mechanical shock. The shape of the convex sealing resin is not particularly limited, but the shape in front view is most preferably a semi-cylindrical shape. A versatile light source can be obtained by making it a semi-cylindrical shape.

(Second substrate)
Examples of the second substrate include a ceramic substrate, a glass epoxy substrate, an aluminum base substrate, a copper base substrate, a printed substrate, and a flexible substrate. The type may be the same as or different from the first substrate. Since it is necessary to prevent the light emitting device from being twisted as a property of the second substrate, a substrate having high hardness is preferable.

A method for manufacturing the light emitting device will be described below.
As a manufacturing method, a case where an insulating substrate is used as the first substrate will be described. For example, a case where a glass epoxy substrate is used will be described. A copper foil for electrical conduction is formed on the entire upper surface (light emitting element mounting surface) and lower surface (second substrate mounting surface) side of the glass epoxy substrate. A through hole (through hole) is provided at a predetermined position. In order to electrically connect the upper surface and the lower surface, copper plating is applied to the wall surface in the through hole. Filling the through hole with copper is preferable in terms of electrical and thermal characteristics, but it is only necessary to obtain sidewall conduction from the viewpoint of time and cost. In that case, in order to improve heat dissipation, it is preferable to fill a material having high thermal conductivity. As a material having high thermal conductivity, solder paste, silver paste, epoxy resin containing metal powder, or the like is preferably used. Thereafter, a copper foil is formed by copper plating on the portion where the material having high thermal conductivity is formed. Thereafter, both surfaces of the first substrate are patterned into a predetermined electrode shape with a photoresist.
Next, the second substrate will be described. As in the case of the first substrate, a case where an insulating substrate is used will be described. For example, when a glass epoxy substrate is used like the first substrate, no copper foil is provided on the upper surface side with respect to the upper surface side (first mounting substrate side) and the lower surface side. If copper foil is provided in advance, it is removed. Similar to the first substrate, the lower surface side is patterned into a predetermined electrode shape with a predetermined photoresist. The obtained 1st board | substrate and 2nd board | substrate are joined via an adhesive sheet. Thereafter, a copper foil is formed on the first substrate and the second substrate by copper plating and electrically connected.

  Further, a light-emitting element is mounted on the first substrate and electrically connected to the first substrate or the second substrate by wire bonding or the like. Furthermore, a phosphor layer is formed on the light emitting element as necessary. The phosphor layer will be described later. The phosphor layer is formed by printing or potting.

Thereafter, a convex sealing resin is formed by compression molding or transfer molding.
Furthermore, it is diced to a predetermined size to form a chip, thereby obtaining a light emitting device.

<Second Embodiment>
5 to 9 show a light emitting device according to the second embodiment. A flat sealing resin is provided between the convex sealing resins. The flat sealing resin may be formed simultaneously with the convex sealing resin, or may be formed separately. The material may be the same as or different from the convex sealing resin. By having a flat sealing resin, it is possible to obtain effects such as prevention of twisting, suppression of firefly phenomenon, and improvement in adhesion to the first substrate. Which effect is strongly expressed? The material is selected as appropriate. For example, a highly advanced material is preferable in order to strongly express the prevention of twisting. In order to suppress the occurrence of the firefly phenomenon, it is preferable to align the material with the convex sealing resin. This is to suppress reflection at the interface between the convex sealing resin and the flat sealing resin. Furthermore, a material having high elasticity is preferable in order to strongly improve the adhesion with the first substrate.

  Further, FIG. 9 illustrates a state in which a phosphor layer is formed for each light emitting element. The phosphor layer includes at least a phosphor powder and a translucent resin, and includes a diffusing material.

  The phosphor layer exhibits a bonding capability with respect to the first substrate at the portion of the translucent resin that is the resin portion, and the phosphor powder portion does not exhibit the bonding capability. Therefore, by having the phosphor layer, the adhesiveness with the first substrate is weakened, and the twisting problem and the adhesiveness problem become remarkable, so that the configuration of the present application becomes more effective. Further, the chromaticity unevenness generated in each phosphor layer is also averaged by the flat sealing resin, and the occurrence of chromaticity unevenness can be suppressed.

Furthermore, for example, when a plurality of light emitting elements have different wavelengths, the emitted light from each other is guided through the flat sealing resin, and color mixing can be promoted.
The phosphor layer will be described below.

(Phosphor layer)
As the phosphor layer, a mixture of a translucent resin and a phosphor is used. More preferably, a diffusing material is contained. As the phosphor, a phosphor containing a phosphor that emits light having different wavelengths by absorbing at least a part of light from the light emitting element. In particular, it is more efficient to convert light from the light emitting element into a longer wavelength. When the light from the light-emitting element is short-wavelength visible light with high energy, YAG: Ce, which is a kind of aluminum oxide phosphor, is preferably used. In particular, the YAG: Ce phosphor emits yellow light that is partially complementary to the blue light emitted from the light emitting element depending on the content thereof. The device can be formed relatively easily.
As the translucent resin, silicone resin, epoxy resin, acrylic resin, or the like is used. Preferably, gelled silicone is used. This is because there is little deterioration and the wire can be protected from mechanical shock.

  Examples of the diffusing material include barium titanate, titanium oxide, aluminum oxide, silicon oxide, silicon dioxide, heavy calcium carbonate, light calcium carbonate, and a mixture containing at least one of these.

<Third Embodiment>
FIG. 10 shows a planar light emitting device 10000 according to the third embodiment. Reference numeral 1011 denotes a light guide plate. Reference numeral 9000 denotes a light emitting device. It is preferable that the light guide plate has a concave portion in the light incident portion in accordance with the shape of the convex sealing resin of the light emitting device. By making each other fit, optical loss can be prevented. In this case, the convex sealing resin is preferably an elastic resin. By using elastic sealing resin, even if the shape of the convex sealing resin and the concave shape of the light guide plate do not completely match, it is possible to eliminate the gap by pressing them against each other. It becomes possible to prevent optical loss. In this case, it is desirable that the convex sealing resin has a semi-cylindrical shape, and the concave portion of the light guide plate is a semi-cylindrical concave portion whose radius of curvature is slightly larger than that of the convex portion of the sealing resin. This is because the air layer can be pushed out in the process of mechanically pushing.

(Light guide plate)
Examples of the material of the light guide plate include acrylic resin, polycarbonate resin, amorphous polyolefin resin, polystyrene resin, norbornene resin, and cycloolefin polymer (COP).

According to the present invention, it is possible to realize a light-emitting device and a planar light-emitting device using the light-emitting device at low cost by using a light-emitting element that is a point light source.

It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the light-emitting device which concerns on this invention. It is a figure which shows one Embodiment of the planar light-emitting device concerning this invention.

Explanation of symbols

101,201,301,401,501,601,701,801,901 ... first substrate
103,203,303,403,503,603,703,803,903 ・ ・ ・ Light emitting element
105,205,305,405,505,605,705,805,905 ・ ・ ・ Convex sealing resin
107,207,307,407,507,607,707,807,907 ... second substrate
509,609,709,809,909 ・ ・ ・ Flat sealing resin
1011 ・ ・ ・ Light guide plate
1000,2000,3000,4000,5000,6000,7000,80000,9000 ・ ・ ・ Light emitting device
10000 ... planar light emitting device

Claims (8)

A rectangular first substrate;
A plurality of light emitting elements arranged in the longitudinal direction of the upper surface of the first substrate;
A plurality of convex sealing resins covering each of the plurality of light emitting elements;
The lower surface of the first substrate, which is disposed in a portion corresponding to the convex sealing resin, is longer in the longitudinal direction of the first substrate than the convex sealing resin, and has a convex end portion A plurality of second substrates positioned between the sealing resin and another convex sealing resin;
A light emitting device.
The light emitting device according to claim 1, wherein a flat sealing resin is provided between the adjacent convex sealing resins.
The light emitting device according to claim 1, wherein the convex sealing resin has a semi-cylindrical shape extending in a short direction.
The light emitting device according to any one of claims 1 to 3, wherein a phosphor layer is disposed for each of the plurality of light emitting elements.
The light emitting device according to claim 2 or 3, wherein the plurality of light emitting elements have different wavelengths.
A light guide plate having a light incident portion;
The light emitting device according to any one of claims 1 to 5, optically connected to the light guide plate,
A planar light emitting device comprising:
The planar light-emitting device according to claim 6, wherein the light incident portion of the light guide plate has a concave portion, and the concave portion and the sealing resin are fitted together.
The planar light-emitting device according to claim 7, wherein the concave portion has a semi-cylindrical shape.

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