WO2013046292A1 - Light emitting module and illuminating apparatus - Google Patents

Abstract

According to the embodiment of the present invention, a light emitting module has semiconductor light emitting elements mounted on a substrate surface, and encapsulating members, which respectively encapsulate the semiconductor light emitting elements at intervals on the substrate surface. The surface of each of the encapsulating members respectively having the semiconductor light emitting elements encapsulated therein includes an annular side surface that linearly rises in the direction to be away from the substrate surface, and a top surface continuous from the side surface, said top surface being on the side separated from the substrate surface.

Description

Light emitting module and lighting apparatus

Embodiments of the present invention relate to a light emitting module in which a semiconductor light emitting element such as an LED (light emitting diode) is mounted on a substrate, and a lighting fixture incorporating the light emitting module.

In recent years, a light-emitting module in which an LED is mounted on a substrate and a lighting apparatus incorporating the light-emitting module are becoming popular.

As a light emitting module, a lens type in which a plurality of LEDs arranged side by side on a substrate are individually sealed with a sealing member, a line type in which a plurality of LEDs are arranged in a row and sealed, or a frame surrounding a plurality of LEDs A bank type in which a (bank) is provided and a plurality of LEDs are sealed together is generally known.

Usually, the sealing member that seals the LED to the substrate is a translucent material including phosphor particles that excite and emit light having a complementary color relationship with the emission color of the LED, and light emitted directly from the LED. Mix to emit white light. For example, an LED that emits blue light is sealed with a sealing member that includes a phosphor that is excited by blue light and emits yellow light or red light.

Special table 2011-515848

However, at present, the above-mentioned types of light emitting modules have not yet obtained a sufficiently satisfactory luminous flux. Also, the light extraction efficiency is not fully satisfactory.

Therefore, it is desired to develop a light emitting module and a lighting fixture with high light extraction efficiency.

The light-emitting module according to the embodiment includes a plurality of semiconductor light-emitting elements mounted on the substrate surface, and a sealing member that seals the semiconductor light-emitting elements on the substrate surface at intervals. The surface of the sealing member that individually seals the semiconductor light emitting element includes a side surface that rises linearly in a direction away from the substrate surface, and a top surface that is continuous with the side surface on the side away from the substrate surface.

According to the light emitting module and the lighting fixture according to the embodiment, the light extraction efficiency can be increased.

Drawing 1 is a sectional view of the lighting fixture concerning an embodiment. FIG. 2 is a front view of the lighting apparatus of FIG. 1 as viewed from the light extraction side. FIG. 3 is a perspective view of the light emitting module according to the embodiment as viewed from the light extraction side. 4 is a partially enlarged cross-sectional view of the light emitting module of FIG. FIG. 5 is a cross-sectional view showing a mounted state of the LED chip incorporated in the light emitting module of FIG. FIG. 6 is a cross-sectional view showing a modification of the sealing member in which the LED chip of the light emitting module of FIG. 3 is sealed. FIG. 7 is a cross-sectional view showing another modification of the sealing member in which the LED chip of the light emitting module of FIG. 3 is sealed. FIG. 8 is a perspective view of a conventional bank type light emitting module as seen from the light extraction side. FIG. 9 is a partially enlarged cross-sectional view of the light emitting module of FIG. FIG. 10 is a perspective view of a conventional line type light emitting module as seen from the light extraction side. FIG. 11 is a perspective view of a conventional lens-type light emitting module as seen from the light extraction side. 12 is a partially enlarged cross-sectional view of the light emitting module of FIGS.

Hereinafter, embodiments will be described in detail with reference to the drawings.
Drawing 1 is a sectional view of lighting fixture 20 concerning an embodiment. Moreover, FIG. 2 is the front view which looked at this lighting fixture 20 from the light extraction side.

The lighting fixture 20 is a downlight using a light emitting module 10 described later as a light source, and includes a case 21 to which the light emitting module 10 is attached and a lighting device 22 that lights the light emitting module 10. The case 21 is made of, for example, aluminum die casting and has a cylindrical shape having openings at both ends, and integrally includes a mounting plate 21a for mounting the light emitting module 10 therein.

The light emitting module 10 is attached to the case 21 by fastening the substrate 11 to the attachment plate 21a with screws. At this time, the copper metal member 14 provided on the back surface of the substrate 11 is in close contact with the flat surface of the aluminum mounting plate 21a. As a result, heat generated from each light emitting unit 13 (to be described later) of the light emitting module 10 is efficiently radiated to the mounting plate 21 a through the substrate 11 and the metal member 14.

The reflector 23 is attached to the inside of the case 21 on the surface side of the light emitting module 10. The reflector 23 is made of a white synthetic resin having light resistance, heat resistance and electrical insulation, for example, polybutylene terephthalate (PBT). The reflector 23 has a circular opening 23a that surrounds the plurality of light emitting portions 13, and a so-called “mortar-shaped” reflecting surface 23b that expands from the edge of the opening 23a.

The lighting device 22 includes a lighting circuit and a power supply circuit for lighting the plurality of light emitting units 13 of the light emitting module 10. The lighting device 22 converts an AC voltage of 100 V obtained from a commercial power source into a DC voltage of 24 V, and supplies a constant DC current to each light emitting unit 13. The lighting device 22 is housed inside the case 21.

A power terminal block 24 for supplying power from the commercial power source to the lighting device 22 is provided at the end of the case 21 on the side opposite to the light extraction side.

A decorative frame 25 is attached to the end of the case 21 on the light extraction side. The decorative frame 25 is adjacent to the light emitting area where the plurality of light emitting units 13 are arranged, and is covered with a transparent cover member 25a.

Further, a support 26 for holding the case 21 on the ceiling X is attached to the end of the case 21 on the light extraction side. The support 26 is a leaf spring.

When attaching the luminaire 20 having the above structure to the ceiling X, first, the power line wired in the installation hole H formed in the ceiling X is connected to the power terminal block 24. Then, the support tool 26 is bent inward by hand, and the tip is inserted into the installation hole H together with the case 21, and then the hand is released from the support tool 26. As a result, the support 26 is restored by its own elasticity and pressed against the inner surface of the installation hole H, and the decorative frame 25 is brought into contact with the ceiling X so as to sandwich the ceiling X between the support 26 and the support X. In this state, the edge of the installation hole H is covered with the decorative frame 25.

When the lighting fixture 20 having the above structure is turned on, most of the light emitted from each light emitting unit 13 is reflected directly or by the reflection surface 23b of the reflector 23 and spreads downward and radiated. At this time, part of the light emitted from the light emitting unit 13 is also reflected on the wiring pattern on the substrate surface and the substrate surface. The surface of the wiring pattern is plated with nickel, silver, gold or the like. The substrate 11 is made of white ceramics. For this reason, the light is well reflected on the surface of the wiring pattern and the surface of the substrate 11 so that the entire lighting fixture 20 can maintain a desired light emission amount.

Further, when the lighting fixture 20 is turned on as described above, the LED chip 2 of each light emitting unit 13 generates heat. In order to prevent deterioration over time due to heat of the light emitting unit 13, it is necessary to efficiently dissipate this heat. In the present embodiment, the metal member 14 attached to the back side of the substrate 11 is made of copper having excellent thermal conductivity, the substrate 11 itself is made of ceramics having good thermal conductivity, and the case 21 is also made of Since it is formed of aluminum having excellent thermal conductivity, the heat generated from the light emitting portion 13 is transmitted from the wiring pattern 12 to the metal member 14 through the insulating substrate 11, and further, the heat transfer surface of the mounting plate 21a. Is transmitted to the case 21 via. The heat transmitted to the case 21 is radiated to the outside of the lighting fixture 20. That is, the heat from each light emitting part 13 is effectively radiated to the outside from the side wall of the case 21 having a large surface area.

As described above, the lighting fixture 20 of this embodiment suppresses a decrease in the light conversion efficiency of each light-emitting unit 13 by the above-described heat dissipation action, and performs illumination with bright illuminance. Moreover, the lifetime of the light emission part 13 is also extended by the above-mentioned heat dissipation action.

FIG. 3 is a perspective view of the light emitting module 10 of this embodiment incorporated in the lighting fixture 20 as seen from the light extraction side. FIG. 4 is a partially enlarged cross-sectional view of the light emitting module 10 of FIG. 1 and 2, the light emitting module 10 having 25 light emitting units 13 has been described. However, the number of the light emitting units 13 may be any number, and at least one may be used. Here, 96 light emitting units 13 are provided. The light emitting module 10 having the above will be described.

The light emitting module 10 includes a substrate 11 having a wiring pattern (not shown) on the surface, a plurality of LED chips 2 (semiconductor light emitting elements) mounted on the surface 11a of the substrate 11 and electrically connected to the wiring pattern, And it has the some sealing member 4 which seals each LED chip 2 on the surface 11a of the board | substrate 11 separately at intervals. Each LED chip 2 and the sealing member 4 that seals it constitute the light emitting unit 13 described above.

The substrate 11 is a DCB (Direct Copper Bonding) substrate, DBA (Direct Brazing Aluminum) substrate, AMC (Active Metal Brazed Copper) substrate, DPC (Direct Plated Copper) substrate, metal substrate, ceramic substrate, glass epoxy substrate, or the like. The DCB substrate is formed by directly bonding a copper plate to a ceramic base material. The DBA substrate is formed by brazing an aluminum plate on a ceramic base material. The AMC substrate is formed by brazing a copper plate on a ceramic base material. The DPC board is a ceramic base material plated with copper. Incidentally, it is possible to use as a ceramic _substrate, Al ₂ O 3, AlN, etc. _Si 3 _{N 4.}

A wiring pattern (not shown) is provided on the surface 11 a of the substrate 11. The wiring pattern is formed by etching copper provided on the substrate surface 11a and patterning the gold pattern or silver plating on the copper pattern via nickel plating.

As shown in FIG. 5, the LED chip 2 of this embodiment is of a type that is flip-chip connected to the substrate surface 11a, and the light emitting layer 2a is close to the substrate surface 11a. Each LED chip 2 has a bump 2b for connecting to the wiring pattern. The LED chip 2 is connected to the wiring pattern on the substrate surface 11a by eutectic solder 3, for example. In addition, silver paste or gold bumps may be used. Note that the LED chip 2 of the present embodiment is a blue light emitting diode that emits blue light when energized.

The sealing member 4 is a translucent resin containing a phosphor. In this embodiment, since the LED chip 2 that emits blue light is used, the sealing member 4 including a phosphor that is excited by blue light and emits yellow light and red light is used. The sealing member 4 is provided on the substrate surface 11 a so as to cover the entire surface of the LED chip 2.

The shape of the sealing member 4 is designed such that the surface thereof includes a side surface 4a that rises linearly in a direction away from the substrate surface 11a, and a top surface 4b that is continuous with the side surface 4a on the side away from the substrate surface 11a. Has been. This shape is a so-called bullet shape.

The side surface 4a may be substantially perpendicular to the substrate surface 11a. For example, as shown in FIG. 6, the side surface 4a may be inclined slightly inward toward the substrate surface 11a (downward in the drawing). As shown in FIG. 7, it may be slightly inclined outward toward the substrate surface 11a. That is, the expression “rising up in a straight line” described above includes those in FIGS. 6 and 7. In particular, when the sealing member 4 is formed by resin injection molding, it is desirable to design the sealing member 4 so as to slightly widen the bottom of the sealing member 4 as shown in FIG.

In addition, the top surface 4b is not limited to a spherical surface, and may be any shape as long as it can increase the light emission efficiency, such as a flat surface, a concave surface, or a concave and convex surface. You can choose. For example, when it is desired to reduce the luminous intensity of the central part and spread the light to the peripheral part, it is preferable to use a concave surface, and to increase the degree of color mixing of the light emitted from the sealing member 4, it is preferable to use an uneven surface. However, the shape of the top surface 4b is, for example, a spherical shape that is smoothly continuous with an end portion (upper end in the drawing) of the side surface 4a that is spaced from the substrate surface 11a. preferable.

Here, specific dimensions, shapes, arrangements, and the like of the respective components of the light emitting module 10 of the present embodiment will be described.
The LED chip 2 of the present embodiment has a flat rectangular block shape, is a square having a side length of 1 mm, and a mounting height from the substrate surface 11a is 0.17 mm. In the present embodiment, 96 LED chips 2 are arranged 8 × 12 vertically and horizontally on the substrate surface 11a. At this time, the pitch of each LED chip 2 was set to 3.0 mm in length and 2.5 mm in width.

The sealing member 4 of the present embodiment has the above-mentioned bullet shape, its side surface 4a has a cylindrical shape with a diameter of 1.7 mm and a height of 0.41 mm, and its top surface 4b has a curvature radius of 1.1 mm. It is made spherical. In this case, the height of the sealing member 4 including the top surface 4b from the substrate surface 11a is about 1 mm.

As described above, since the sealing member 4 has the side surface 4a that rises substantially perpendicularly from the substrate surface 11a, in addition to the light directly emitted through the side surface 4a, the light toward the substrate surface 11a and the side surface 4a A large amount of light that is effective for illumination in the light extraction direction, such as light that is reflected on the inside and emitted through the top surface 4b, can be extracted.

In addition, by adopting the above-described bullet-shaped sealing member 4 and designing the pitch between the LED chips 2 to be constant, the light extraction efficiency can be further increased. That is, at a pitch at which light emitted from one light emitting unit 13 through the sealing member 4 is not absorbed by the sealing member 4 of the adjacent light emitting unit 13 and does not cause luminance unevenness. It is desirable to design.

Furthermore, in order to design each part of the light emitting part 13 to a desired dimension, it is desirable to mount the LED chip 2 on the substrate surface 11a as in the present embodiment.

If the face-up type LED chip is wire-bonded to the wiring pattern on the substrate surface, it is necessary to connect the bonding wire by arranging an electrode pad at the end of the chip on the light extraction side, resulting in a decrease in luminous efficiency. At the same time, the diameter of the sealing member is increased.

As described above, when the diameter of the sealing member is increased, the light emitted from the LED chip 2 may be absorbed before exiting the sealing member, and the light emission efficiency may be decreased accordingly. . At the same time, if the pitch between the chips is not changed, the distance between the sealing member surfaces in the adjacent light emitting parts is shortened, and light is reabsorbed by the adjacent light emitting parts, and the luminous efficiency is accordingly increased. descend. Furthermore, when the diameter of the sealing member is increased, the material cost is increased accordingly, and the module is also increased in size.

In order to investigate the characteristics of the light emitting module 10 of the present embodiment described above, a conventional bank type light emitting module 30 as shown in FIGS. The light emitting module 30 has a structure in which a bank 32 surrounding all the LED chips 2 arranged in the vertical and horizontal directions is provided, and a sealing member 34 is filled in the bank 32 to seal all the LED chips 2. Other structures have the same structure as the light emitting module 10 of the above-described embodiment.

Then, the light emitting module 10 of the present embodiment and the conventional light emitting module 30 were respectively lit at If = 350 mA per chip. As a result, the conventional bank type light emitting module 30 emitted light at a correlated color temperature of 5037K, and a light flux of 10900 lm was obtained. On the other hand, the light emitting module 10 using the bullet-shaped sealing member 4 of the present embodiment emitted light with a correlated color temperature of 4967K, and a light flux of 14000 lm was obtained. That is, when the light emitting module 10 of the present embodiment and the conventional light emitting module 30 are lit under the same conditions, the light emitting module 10 using the shell-shaped sealing member 4 of the present embodiment is different from the conventional bank type. The light extraction efficiency of 1.29 times could be obtained.

For comparison, a conventional line type light emitting module 40 as shown in FIG. 10 and a conventional lens type light emitting module 50 as shown in FIG. And turned on under the same conditions. As a result, in the line type light emitting module 40, the luminous flux was 8409lm at the correlated color temperature 5043K, and in the lens type light emitting module 50, the luminous flux was 9423lm at the correlated color temperature 5018K. A cross-sectional view of these conventional light emitting modules 40 and 50 is shown in FIG.

As described above, according to the present embodiment, the light extraction efficiency can be increased and the luminous flux can be increased as compared with the conventional bank type, line type, or lens type light emitting modules 30, 40, and 50. it can. Further, according to the present embodiment, the amount of a relatively expensive sealing member used can be reduced and the material cost can be reduced as compared with the conventional bank type light emitting module 30 and line type light emitting module 40. .

In particular, in the conventional bank-type light emitting module 30, since all the LED chips 2 are sealed with a continuous sealing member, the yellow light emitted by the phosphor being excited by the blue light emitted from each LED chip 2 is emitted. However, it is reabsorbed by the phosphors and banks of the sealing member, and the power efficiency (lm / W) is reduced accordingly. This is also true for the line-type light emitting module 40. On the other hand, in the light emitting module 10 using the bullet-shaped sealing member 4 of the present embodiment, each LED chip 2 can be individually sealed with a space therebetween, and thus such a problem of reabsorption occurs. Absent.

Here, in order to investigate the appropriate value of the height of the side surface 4a of the sealing member 4 that can achieve the effect of the above-described embodiment, the height of the side surface 4a is determined based on the mounting height of the LED chip 2. Various changes were made, and the light emission characteristics of the light emitting module 10 in each case were measured. As a result, when the height t of the side surface 4a of the sealing member 4 is set to a value satisfying 0.4 <t / d <1.5 with respect to the mounting height d of the LED chip 2, good characteristics are obtained. It turns out that it is obtained.

In other words, when t / d is set to 0.4 or less, the lens type is approached, and in order to obtain sufficiently satisfactory light emission characteristics, it is necessary to increase the phosphor concentration, which makes it difficult to manufacture the module. become. Moreover, when t / d is set to 1.5 or more, the light passing through the side surface 4a of the sealing member 4 increases, and the light easily enters the sealing member 4 of the adjacent light emitting portion 13, and the light emission efficiency accordingly. Decreases. In this case, in order to maintain the light emission efficiency, it is necessary to increase the pitch between the adjacent light emitting portions 13, and the light emitting area of the module becomes large. For this reason, it is desirable to set the height t of the side surface 4a of the sealing member 4 to a value satisfying 0.4 <t / d <1.5.

Also, in order to investigate the appropriate pitch of the LED chip 2, the inter-chip pitch was variously changed based on the length of one side of the LED chip 2, and the light emission characteristics of the light emitting module 10 in each case were measured. As a result, it has been found that good characteristics can be obtained when the pitch is set to 2 to 3.5 times the length of one side of the LED chip 2.

That is, when the pitch of the LED chips 2 is set to be twice or less the length of one side of the LED chip 2, the surfaces of the sealing member 4 that seals each LED chip 2 come close to each other, and one light emitting portion The white light and blue light emitted from 13 are reabsorbed by the other light emitting unit 13 adjacent thereto, and the light emission efficiency is reduced accordingly. Further, when the pitch of the LED chips 2 is set to be 3.5 times or more of the length of one side of the LED chip 2, although the light emission efficiency is hardly lowered, the light emitting area of the light emitting module 10 as a whole increases, and the lighting fixture 20 also becomes large. For this reason, it is desirable to set the pitch of the LED chips 2 to be larger than twice the length of one side of the LED chip 2 and smaller than 3.5 times.

Furthermore, in order to investigate the appropriate value of the diameter R of the sealing member 4, the diameter R of the sealing member 4 is variously changed on the basis of the diagonal length L of the LED chip 2, and the light emission of the light emitting module 10 in each case Characteristics were measured. As a result, good characteristics can be obtained when the diameter R of the sealing member 4 is set to a value satisfying 1.13 <R / L <1.5 with respect to the diagonal length L of the LED chip 2. I understood.

That is, when R / L is set to 1.13 or less, the side surface 4a of the sealing member 4 comes close to the corner of the LED chip 2, and the reliability of sealing is lowered and the LED chip 2 is released. The ratio of the emitted blue light that is emitted without exciting the phosphor increases, causing uneven color. In this case, the amount of light reabsorbed by the adjacent light emitting units 13 is increased, and the light emission efficiency is lowered.

On the other hand, when R / L is set to 1.5 or more, the distance between the LED chip 2 and the side surface 4a of the sealing member 4 is increased, and before the light emitted from the LED chip 2 is emitted from the sealing member 4. The ratio of the light absorbed is increased, and the luminous efficiency is reduced accordingly. At the same time, when the pitch between the chips is not changed, the distance between the sealing members 4 between the adjacent light emitting portions 13 is shortened, and light is reabsorbed by the adjacent light emitting portions 13, and the light emission correspondingly. Efficiency is reduced. For this reason, it is desirable to set the diameter R of the sealing member 4 to a value satisfying 1.13 <R / L <1.5 with respect to the diagonal length L of the LED chip 2.

The above-described embodiment is presented as an example, and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope of the present invention and the gist thereof, and are also included in the invention described in the claims and the equivalent scope thereof.

For example, in the above-described embodiment, the case where the present invention is applied to a downlight as an example of a lighting fixture has been described. However, the present invention is not limited thereto, and the present invention may be applied to other lighting fixtures such as a light bulb and a ceiling light. .

In the above-described embodiment, the light emitting module 10 having the flip chip type LED chip 2 has been described. However, the present invention is not limited to this, and the present invention can also be applied to a light emitting module having a face up type LED chip. In this case, as the light emitting layer of the LED chip moves away from the substrate surface 11a, the height of the side surface 4a of the sealing member 4 becomes higher than the height of the light emitting layer of the LED chip.

The light emitting module and the lighting fixture of the embodiment can increase the light extraction efficiency and increase the luminous flux.

2 ... LED chip, 4 ... sealing member, 4a ... side face, 4b ... top face, 10 ... light emitting module, 11 ... substrate, 11a ... substrate surface, 13 ... light emitting part, 20 ... lighting fixture.

Claims (6)

A substrate having a wiring pattern on its surface;
A plurality of semiconductor light emitting devices mounted on the substrate surface and connected to the wiring pattern;
A sealing member that seals the semiconductor light emitting element on the surface of the substrate individually with a gap therebetween,
The surface of the sealing member includes a side surface that rises linearly in a direction away from the substrate surface, and a top surface that is continuous with the side surface on a side away from the substrate surface. The rising height t from the substrate surface of the side surface of the sealing member is, when the mounting height from the substrate surface of the semiconductor light emitting element is d,
0.4 <t / d <1.5
The light emitting module of Claim 1 set to the value which satisfy | fills. The light emitting module according to claim 2, wherein a plurality of the semiconductor light emitting elements are mounted on the substrate surface at a pitch of 2 to 3.5 times the length of one side of the semiconductor light emitting element. The diameter R of the sealing member that individually seals the semiconductor light emitting element is, when the length of the diagonal line of the semiconductor light emitting element is L,
1.13 <R / L <1.5
The light emitting module according to claim 3, wherein the light emitting module is set to a value satisfying The light emitting module according to claim 1, wherein the semiconductor light emitting element is mounted on the substrate surface by flip chip. A lighting fixture incorporating the light emitting module according to any one of claims 1 to 5.

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