JPH0510369Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a surface emitting device in which a plurality of LEDs are arranged in a common housing.

<Prior Art> As a conventional example, FIG. 4 is a front view thereof, and FIG. 5 is a sectional view thereof. As shown in Figure 5, when the printed circuit board is entirely covered with mold resin,
Since stress is generated near the interface between the printed circuit board 3 and the molded resin layer 4 due to thermal stress and hardening of the resin, the LED is designed to reduce the stress.
The structure was such that the department was divided into small sections. In addition, as a mold resin, epoxy resin is better than silicone because it is difficult to mold LED chips and wires (not shown) after curing.
Although it is desirable to use epoxy resin because it is superior in protecting it from external forces, silicone resin has been used to reduce the generation of stress. However, because silicon is flexible, it is easily affected by external forces.
Because this would affect the LEDs, it was necessary to take measures to protect the LEDs, such as attaching an acrylic plate to the front.

<Problems to be Solved by the Invention> The present invention aims to further improve the conventional technology described above. That is, the purpose is to almost eliminate the generation of stress due to heat generation and hardening of the resin, and to improve the forward reflection efficiency.

<Means for Solving the Problems> In the surface emitting device of the present invention, a plurality of through holes each having a polygonal shape of four or more sides are arranged at a predetermined position on the bottom of a reflector having a dish-like shape, and the through holes are In a surface emitting element in which a printed wiring board with a plurality of LED chips arranged at corresponding positions is assembled on the back surface of the reflector, and the plurality of LED chips are molded with resin, the through hole is It is characterized in that it is surrounded by a wall that projects to the periphery and forms a boundary, and that a slope is formed between the ridgeline of the wall and each side around the through hole.

<Function> Due to its structure, the surface emitting device of the present invention is not affected by stress because each small section can be molded with a small amount of epoxy resin. Furthermore, since the slope formed around the LED serves as a reflective surface that reflects light forward, uneven brightness on the light emitting surface is improved. Therefore, surface emitting luminance increases.

<Example> Fig. 1 is a front view of an embodiment of the present invention, Fig. 2 is a cross-sectional view of the embodiment of the present invention in Fig. 1 taken along A-A', and Fig. 3 is a cutaway of the reflector. FIG. Inner surface 1a of outer frame portion of reflector 1
is inclined and forms a reflective surface. Also reflector 1
A plurality of regular octagonal through holes are provided at predetermined positions on the bottom of the holder, and the area occupied by the through holes is 20% to 30% of the bottom. Printed circuit board 3
is fixed to the back surface of the reflector 1 and divided into small sections. The small section has a regular octagon as its bottom corresponding to the through hole at the bottom of the reflector 1, and is surrounded by a wall that protrudes around the bottom to form a boundary, and the ridgeline of the wall and each side of the regular octagon The structure is such that a slope is formed between the two. Further, in the small section, a plurality of LED chips 2 are regularly arranged at respective positions on the bottom corresponding to the through holes, and a molded resin layer 4 made of epoxy resin is formed to cover these LED chips 2.

The light emitted from the LED chip 2 passes through the molded resin layer 4 and is reflected on the inner surface 1a of the outer frame portion of the reflector 1, and is otherwise reflected on the wall portions forming the small sections. These transmitted light and reflected light become surface emitted light and exit to the outside. In the embodiment of the present invention, the forward reflection efficiency is improved by providing a large number of the above-mentioned reflecting surfaces.

Further, with the above structure, the amount of resin filled in each small section is reduced to about half compared to the conventional one, so that almost no thermal stress occurs near the interface between the printed circuit board 3 and the molded resin layer 4. Therefore, the mold resin layer 4 in each section
There is almost no force applied to the LED chip 2 and wire 8. Furthermore, there is almost no attenuation of the amount of light due to the molded resin layer 4.

<Effects of the invention> As explained above, each LED has many slopes around it, which improves forward reflection efficiency, and the amount of molding resin filled in each divided small section is reduced by the structure of the invention. According to this, a smaller amount is required compared to the conventional method. Therefore, there is almost no influence of stress due to the molded resin layer 4 covering the printed circuit board. Furthermore, since the epoxy resin does not undergo elastic deformation even when an external force is applied after curing, the acrylic plate that is the protective plate conventionally provided on the front surface of the surface emitting element becomes unnecessary.

Furthermore, since only the LED section of the printed circuit board occupies the through hole, no components other than the LED can be seen from the surface. Further, there is no need to perform unnecessary processing such as reflective treatment on the printed circuit board, and the manufacturing process thereof is simplified.

Therefore, the surface emitting device according to the present invention has clearer colored light, improved light emission quality, and further improved reliability. In addition, the product value has been significantly improved due to the aesthetic appearance.

[Brief explanation of the drawing]

Figure 1 is a front view of the embodiment of the present invention, Figure 2 is a cross-sectional view of the embodiment of the present invention in Figure 1 taken along line A-A', and Figure 3 is a cross-sectional view of the reflector. be. FIG. 4 is a plan view of the conventional example, and FIG. 5 is a sectional view of the conventional example. 1...Reflector, 2...LED chip, 3...
...Printed circuit board, 4...Mold resin layer, 5...
Boundary wall portion, 6... Through hole, 7... Wire, 8...
Acrylic plate.

Claims (1)

[Scope of utility model registration request] A print in which a plurality of through holes in the shape of a polygon larger than a square are arranged at predetermined positions on the bottom of a reflector having a dish-shaped shape, and a plurality of LED chips are arranged in each position corresponding to the through holes. In a surface emitting device in which a wiring board is assembled on the back surface of the reflector and the plurality of LED chips are resin-molded, the through hole is surrounded by a wall that protrudes to the periphery and forms a boundary; What is claimed is: 1. A surface-emitting device, characterized in that a slope is formed between the ridgeline of the through-hole and each side around the through-hole.