JP2002280617A - Illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminating device capable of taking out uniform parallel light by uniformly mixing the light having respective colors emitted from a plurality of light emitting diode elements. SOLUTION: The illumination device is constructed in such a manner that two or more transparent light diffusing members each entirely made of a projected curved surface is provided for one light emitting diode so as to cover a plurality of light emitting diodes arranged on a substrate, and that the light emitting diodes and the light diffusing member are molded with a resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device using a light emitting diode.

[0002]

2. Description of the Related Art In recent years, blue and white light emitting diode elements have been put into practical use and their efficiency has been improved, so that illumination using light emitting diodes is expected to have higher efficiency and longer life. I'm taking a bath. At present, since the light output of a single light emitting diode element is low, it is necessary to integrate a plurality of light emitting diode elements for use in lighting applications. Further, the light emitted from the light emitting diode is
Since it has directivity as its characteristic, the brightness is high when viewed from the front and dazzling when viewed directly. This may have an adverse effect on the user's eyes. For use in lighting applications, use a diffuser or arrange a spherical lens on the surface of the light emitting diode as described in JP-A-11-266036. Therefore, it was necessary to extract uniform light.

[0003] In order to realize a white lighting device using a light emitting diode, a method using a white light emitting diode element and a light emitting diode element of three or more colors such as red, green and blue are mixed to obtain a white light. There is a way to get The former is an InGaN-based blue light emitting diode that excites a YAG phosphor that emits yellow light, and a white light emitting diode that obtains white by mixing blue and yellow has already been put into practical use.
Since the one-chip system is used, there is an advantage that the design of the driving circuit is easy. On the other hand, the latter multi-chip method is suitable for lighting applications requiring high color rendering properties and variable colors.

[0004]

In the prior art using a spherical lens, one spherical lens is arranged for each light emitting element, so that color unevenness caused by light mixing of three or more colors cannot be eliminated. . In addition, the size of the bare chip of the main light emitting diode at present is about 200 μm to 40 μm.
Although it is 0 μm, it is difficult to arrange a spherical lens in consideration of parallel light emission in accordance with each light emitting element, because high precision mounting is required and manufacturing is difficult.

As another solution, it is conceivable to reduce the interval between the light emitting diode elements and increase the integration density. However, at the same time, the amount of heat generated also increases, and the efficiency of the light emitting diode elements decreases and the life is shortened. Invite. If the distance between the irradiation surface and the illuminating device is increased, the color unevenness decreases, but the illuminance also decreases. In addition, when a diffusion plate is used, there is a problem in that when the light emitted from the light emitting diode element passes through the diffusion plate, the brightness is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an illuminating device capable of uniformly mixing light of each color emitted from a plurality of light emitting diode elements and extracting uniform parallel light.

[0007]

In order to solve the above-mentioned problems, a lighting device according to the present invention comprises a transparent light-scattering member having a convex curved surface as a whole so as to cover a plurality of light emitting diodes arranged on a substrate. In addition, two or more light emitting diodes are provided for one light emitting diode, and the light emitting diode and the light dispersion member are resin-molded.

Thus, the light emitted from the plurality of light emitting diode elements can be mixed without unevenness, and white light or a desired emission color with high color rendering properties and no color unevenness can be obtained. Light can be extracted. Also, it can be easily manufactured as compared with the prior art.

Further, in the lighting device of the present invention, it is preferable that the plurality of light emitting diodes are arranged at least in proximity to each of the basic colors of red, green and blue.

By arranging light emitting diodes close to each other for each basic color, when the same number of light dispersing members are used, uneven light mixing is further reduced. And the thickness can be further reduced.

In the lighting device of the present invention, it is preferable that the light dispersion member is a transparent spherical or substantially spherical glass or resin.

By using transparent beads or the like as the light dispersing member, light of each color emitted from the light emitting diode element having a plurality of light emitting colors can be mixed without unevenness, and high parallelism or uniform parallel of variable colors can be obtained. Since light can be extracted and the transmittance is high, a higher light output can be obtained.

In the lighting device of the present invention, it is preferable that powder having a light diffusion effect is mixed in the resin mold.

Thus, when the same number of light dispersion members are used, uneven light mixing is further reduced, and when light mixing unevenness is of the same level, the number of light scattering members can be further reduced, and the thickness can be further reduced. Becomes

Further, in the lighting device of the present invention, it is preferable that the resin mold is in contact with a component of the lighting device made of resin, ceramics or metal.

This makes it possible to dissipate the heat generated by the light emitting diode element through the components of the lighting device, thereby solving the problems of reduced light emission efficiency and shortened life of the element due to heat generated during high density integration of the element. it can.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) A first embodiment of the present invention shown in FIGS. 1 and 2 is to cover a bare chip of a light emitting diode.
This is a lighting device having a structure in which glass beads are resin-molded as a light dispersion member.

The bare chip mounting portion 1 of the light emitting diode lighting device of the present invention shown in FIG. 1 has a heat dissipation multilayer substrate 2 and four colors of red (R), green (G), blue (B) and yellow (Y). , Light emitting diode bare chips 3 to 6, glass beads 7, and a transparent epoxy resin mold 8. As shown in FIG. 2, the red, green, blue, and yellow 4
A total of four bare chips 3 to 6 are arranged one by one to form one bare chip unit 9. At least two glass beads 7 as a light dispersion member are arranged so as to cover the bare chips 3 to 6 with respect to at least one bare chip, and are integrally formed of epoxy resin so as to fix them. In the present embodiment, an example using four-color light-emitting diodes has been described, but three primary colors of light, red, green, and blue, and other combinations of a plurality of colors are also possible.

Generally, in a lighting device using a plurality of light emitting diode elements, unless the light is diffused by a diffusion plate or the like,
Color unevenness corresponding to each light emitting diode element occurs on the irradiation surface. In the light-emitting diode illuminating device having the structure of the present embodiment, light of each color emitted from the light-emitting diode is mixed with each other while reflecting in a plurality of glass beads, and is uniformly parallel without external color unevenness. It can be extracted as light. According to this configuration, color unevenness does not occur even when the irradiation surface and the light emitting surface of the lighting device are close to each other. In addition, unlike the diffusion plate, since there is no metal fine particles such as alumina fine particles as a disturbing body, there is almost no decrease in luminance.

(Embodiment 2) A second embodiment of the present invention shown in FIGS. 3 and 4 is a lighting device having a structure in which a mold resin is brought into contact with a lamp housing.

A light emitting diode lighting device 10 of the present invention shown in FIG. 3 includes a heat radiation multilayer substrate 2, a light emitting diode bare chip 3 of four colors of red (R), green (G), blue (B) and yellow (Y).
6, a glass bead 7, a transparent epoxy resin mold 8, an aluminum lamp housing 11, a lighting circuit 12, and an E26 base 13. On the surface of the heat radiation multilayer substrate 2,
The bare chips 3 to 6 are mounted, and the lighting circuit 12 is arranged on the back surface. The heat dissipating multilayer substrate 2 is arranged in the lamp housing 11 and is fixed by fixing parts (not shown) in the lamp housing 11. In addition, bare chips 3-6
On the upper surface, glass beads 7 are arranged, and a mold resin 8 is provided.
Is sealed by. The end surface of the mold resin 8 is in close contact with the lamp housing 11. Therefore, bare chips 3 to
The heat generated from 6 is made uniform by the mold resin 8, and the heat can be released from the end face to the outside through the lamp housing 11 and the base 13.

FIG. 4 is a front view of the lighting device according to the present embodiment as viewed from the lamp irradiation surface. The lamp housing 11 has a circular shape with an outer diameter of 90 mm and an outer diameter of a light emitting surface of 50 mm, and a square heat-radiating multilayer substrate 2 with a side of 35 mm is disposed on the upper surface thereof. Further, on the upper surface thereof, a light emitting diode bare chip unit 9 having a square shape of about 1.1 mm on a side.
But 16 units vertically and horizontally at intervals of about 1.1 mm, for a total of 256
Units are arranged. Each bare chip unit 9
As in Embodiment 1, as shown in FIG. 2, each of the color light emitting diode bare chips 3 to 6 each having a square shape with a side length of 360 μm is arranged close to four by one. Have been. Therefore, 256 bare chip units and 1024 light emitting diode bare chips 3 to 6 in total for each color are mounted on this substrate. On the upper surface of the heat dissipating multilayer substrate 2 on which the light emitting diode bare chips 3 to 6 are mounted, a total of 3000 glass beads, each having a diameter of 200 μm, are scattered on each of the bare chips 3 to 6 for a total of 3000 particles, and the thickness is 2 mm. Is sealed by a transparent mold resin 8.

The light-dispersing member used in the present invention is not particularly limited as long as it is a transparent member having a convex curved surface as a whole. Preferably, the glass or resin is substantially spherical. The type of the resin is not particularly limited, but a resin having excellent heat resistance is preferably used. As a specific example of the light dispersion member, for example, a diameter of 100 μm to
1.0 mm glass beads and the like.

As the resin for molding, for example, a transparent epoxy resin, acrylic resin, silicone resin or the like is used. In order to further reduce uneven light mixing, it is preferable that powder having a light diffusion effect is mixed in the mold resin in a volume ratio of 5 to 30 with respect to the mold resin 100. As the powder having a light diffusion effect, inorganic or organic fine particles having an average particle diameter of 10 μm to 1.0 mm can be used. For example, silica, a mixture of methacrylic acid ester and silica, quartz, transparent quartz such as amorphous quartz, etc. Examples include fine particles and spherical glass beads.

In the present invention, two or more light dispersion members described above are provided for each bare chip of a light emitting diode.
It is preferable to provide zero. The light emitting diodes are arranged at least for each of the basic colors of red, green and blue. Therefore, when there are four basic colors, for example, red, green,
One unit is formed by disposing one bare chip of each color of blue and yellow, and the arrangement interval (distance) is shorter than the distance between each unit.

In the present invention, a ceramic or metal lamp housing or the like is used as a component of the lighting device to be brought into contact with the mold resin.

Hereinafter, the present invention will be described more specifically with reference to examples.

[0028]

EXAMPLES (Example 1) In order to confirm how much the color unevenness is reduced in the lighting device of Embodiment 2,
The chromaticity distribution of the irradiated surface was measured. Using the lighting device of the present embodiment, the chromaticity distribution of the illuminated surface illuminated by the present lighting device was measured using a color luminance meter (BM-7, manufactured by TOPCON) for the case where there was no glass bead 7 and for the case where there was no glass bead 7. Measured. The result is shown in FIG. The difference between the maximum value and the minimum value of the chromaticity x and y is represented by Δx and Δy, respectively.

As is clear from FIG. 5, the glass beads 7
Without, Δx and Δy are 0.484 and 0.4, respectively.
It was 69, but when the glass beads 7 of this example were present, they were 0.145 and 0.150, respectively, indicating that the color unevenness was reduced by about 70%.

(Embodiment 2) In the embodiment 1, the case where one side of the bare chips 3 to 6 is 360 μm and the diameter of the glass beads 7 is 200 μm is shown.
The measurement was similarly performed when the diameter of the sample was 100 μm to 1.0 mm. As a result, it was found that the color unevenness was reduced by about 70% as compared with the case without the glass beads.

[0031]

As described above, according to the present invention,
In a lighting device using a light emitting diode bare chip having a plurality of emission colors, a transparent light dispersion member such as two or more glass beads is molded with resin on the upper surface of one bare chip. Are dispersed and mixed when passing through glass beads, and uneven light mixing can be eliminated. For this reason, it is possible to obtain not only white light without color unevenness but also a desired emission color without color unevenness. Further, the heat generated by the integration of the bare chip is diffused by the mold resin and is further brought into contact with components of the lighting device such as a lamp housing, so that heat can be radiated to the outside. As a result, it is possible to avoid a decrease in luminous efficiency and a shortened life due to a rise in temperature.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lighting device according to a first embodiment of the present invention.

FIG. 2 is a layout diagram of bare chips of the lighting device according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a lighting device according to a second embodiment of the present invention.

FIG. 4 is a front view of a lighting device according to a second embodiment of the present invention.

FIG. 5 is a chromaticity unevenness comparison diagram of the illumination device according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting diode bare chip mounting part 2 Heat dissipation multilayer board 3 Light emitting diode bare chip (red) 4 Light emitting diode bare chip (green) 5 Light emitting diode bare chip (blue) 6 Light emitting diode bare chip (yellow) 7 Glass beads 8 Mold resin 9 Bare chip unit 10 Light emitting diode Lighting device 11 Lamp housing 12 Lighting circuit 13 Base

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsushi Tamura 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Terms (reference) 5F041 AA11 AA14 DA14 DA20 DA44 DA46 DB08 DC82 EE25

Claims (5)

[Claims] 1. A plurality of transparent light dispersing members each having a convex curved surface are provided for each of the light emitting diodes so as to cover a plurality of light emitting diodes arranged on a substrate,
A lighting device, wherein the light emitting diode and the light dispersion member are resin-molded. 2. The lighting device according to claim 1, wherein the plurality of light emitting diodes are arranged in proximity to at least each of the basic colors of red, green, and blue. 3. The lighting device according to claim 1, wherein the light dispersion member is a transparent spherical or substantially spherical glass or resin. 4. The resin mold according to claim 1, wherein a powder having a light diffusion effect is mixed in said resin mold.
The lighting device according to any one of the above. 5. The lighting device according to claim 1, wherein the resin mold is in contact with a component of the lighting device made of resin, ceramics, or metal.