JPH01103885A - Led surface illuminating device - Google Patents

Abstract

PURPOSE:To position a white color reflecting section very accurately so as to obtain an excellent reflectance by a method wherein the white color reflecting section which is to be positioned above a LED chip is made to be previously formed with the LED chip in one piece. CONSTITUTION:A white color reflecting section 13e which is to be arranged above a LED chip is made to be previously formed with the LED chip 13 in one piece. The white color reflecting section 13e can be very accurately positioned without making the position alignment of the section 13e with the LED chip 13 over again, and nothing prevents a transparent resin from flowing when a resin molding is performed, so that the transparent resin is made to flow freely within a required range. As the inside face of a frame-like ramp house 14 has not a stepped section that a conventional one has and is formed as a reflective surface, so that the inside face is extremely excellent in reflectance, a transparent sheet can be dispensed with, and manufacturing processes can be decreased in number and cost is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an LED surface light source device that provides uniform back illumination using LEDs.

[Conventional technology and problems]

Conventionally, this type of LED surface light source device is configured as shown in FIG. 3, for example. That is, this LED surface light source device 1
First, on the top surface 2a of a plate material 2 such as a printed circuit board whose top surface 2a is made white by printing or the like, a plurality of (two in the drawing) LED elements 3 are placed at an appropriate interval, for example, an interval of about 1011. It is mounted by attaching and wire bonding with gold wire at 3 degrees. Next, plate material 2
A frame-shaped lamp house 4 is attached along the periphery of the upper surface 2a with adhesive or the like. This frame-shaped lamp house 4 has an upwardly directed step portion 4a at the middle height of its inner surface.
It is provided with a tapered portion 4b that expands upwardly on the upper side. Subsequently, a transparent sheet 5 made of acrylic resin, polycarbonate, polyester, etc. is placed horizontally on the stepped portion 4a within the lamp house 4. This transparent sheet 5 is provided with a white reflective part 6 formed by printing such as silk printing in front at a position corresponding to the LED element 3 on its surface, and is not further provided with the white reflective part 6. A plurality of through holes 7 are provided in the portion.

Next, a transparent resin is filled in the inner space of the lamp house 4 up to the upper part of the transparent sheet 5 so as to leave a space S above it, and is hardened to form a transparent resin layer 8. At this time, the transparent resin layer 8 has through holes 7 provided in the transparent sheet 5.
It also enters below the transparent sheet 5 through the transparent resin layer 8, whereby the transparent sheet 5 is integrally molded into the transparent resin layer 8. Finally, the LED surface light source device 1 is completed by pasting the light diffusing plate 9 on the lamp house 4 so as to cover the entire lamp house 4.

However, in the LED surface light source device 1 configured as described above, it is not easy to align the white reflective portion 6 provided on the transparent sheet 5 and the LED elements 3, and the transparent resin layer 8 is 5 through the through holes 7 of the transparent sheet 5, and the lamp house 4 becomes difficult to flow downward through the transparent sheet 5.
Since the inner surface of the lamp house 4 is provided with a stepped portion 4a for receiving the transparent sheet 5, the reflection efficiency by the inner surface of the lamp house 4 is not very good. Due to the presence of the element 3, there were drawbacks such as poor workability when placing the transparent sheet 5 on the stepped portion 4a.

[Purpose of the invention]

In view of the above points, the present invention allows easy alignment of the LED element and the white reflector to be placed above it,
Another object of the present invention is to provide an LED surface light source device in which the transparent resin flows easily to all the places to be filled, the reflection efficiency of the lamp house is improved, and the structure and assembly are simple.

[Means and actions for solving the problem] The above purpose is:
According to the present invention, a plate material such as a printed circuit board whose upper surface is white by printing or the like, and an LED chip is arranged on the upper surface of this plate material at an appropriate interval and is made of transparent resin by placing LED chips on the chip substrate in advance. A plurality of LED elements each having a white reflective part formed on the upper surface of a resin-molded chip LED, a frame-shaped lamp house attached along the periphery of the upper surface of the plate, and an inner space of the lamp house. A transparent resin layer that is filled and hardened so as to leave a space above it,
This is achieved by an LED surface light source device including a light diffusing plate attached to the lamp house so as to cover the entire lamp house.

According to this invention, since the white reflective part to be disposed above the LED chip is formed integrally with the LED chip in advance, the white reflective part does not need to be repositioned with respect to the LED chip. Because the positioning is extremely accurate and there is nothing that impedes the flow of the transparent resin during resin molding, the transparent resin can flow well within the predetermined range, and the inner surface of the frame-shaped lamp house is Since it does not have a step and is formed only as a reflective surface, this inner surface provides extremely good reflection efficiency, and also eliminates the need for a transparent sheet as in the conventional case. This reduces the number of manufacturing steps and reduces costs.

〔Example〕

The present invention will be further explained below based on an embodiment shown in the drawings.

FIG. 1 is a sectional view of an LED surface light source device according to the present invention, and this LED surface light source device 11 is manufactured, for example, as described below.

That is, first, on the upper surface 12a of a plate material 12 such as a printed circuit board whose upper surface 12a is made white by printing or the like, a plurality of (two in FIG. An LED element 13 is arranged. Here, the LED element 13 is mounted on a chip substrate 13a in advance.
The LED chip 13b is mounted on top and mounted by wire bonding with a gold wire 13c, and then the chip L is molded with a transparent resin 13d.
ED13' and finally this chip LED13"
A white reflecting portion 13e having light diffusing properties is formed by printing such as silk printing on the flat upper surface of the mirror.

Next, the frame-shaped lamp house 14 is attached along the periphery of the upper surface 12a of the plate material 12 using an adhesive or the like. In this example, the frame-shaped lamp house 14 includes a tapered portion 14a that expands upward on its inner surface.

Next, a transparent resin is filled into the inner space of the lamp house 14 so as to leave a space S above it, and is cured.
A transparent resin layer 15 is formed. At that time 1, transparent resin layer 15
also extends around the sides of the LED element 13, whereby the LED element 13 is integrally molded in the transparent resin layer 15. Finally, by pasting the light diffusing plate 16 on the lamp house 14 so as to cover the entire lamp house 14, the LED
The surface light source device 11 is completed.

The LED surface light source device according to the present invention is constructed as described above, and the light emitted from the LED elements 13 in this LED surface light source device 11 is diffused as shown in FIG. 2.

That is, LED element 13. The light beam emitted from the LED chip 13b passes through the transparent resin 13d and reaches the white reflective part 13e formed on the top surface, where it is reflected and diffused, and the reflected light is reflected and diffused by the top surface 12a of the plate material 12. The light passes through the transparent resin layer 15 to reach the light diffusing plate 16, and illuminates the light diffusing plate 16 from the back side. Also, LED
The light ray L2 emitted from the LED chip 13b of the element 131 passes through the transparent resin layer 15, is mostly reflected on the surface of the transparent resin layer 15, is reflected and diffused on the surface 12a of the plate material 12, and is reflected again on the transparent resin layer. 15 to reach the light diffusing plate 16, and the light diffusing plate 16 is illuminated. moreover,
LED element 13. The light ray L emitted from the LED chip 13b of
3 passes through the transparent resin layer 15, is totally reflected on its surface because it exceeds a critical angle, is reflected and diffused by the white reflective part 13e formed on the top surface of the LED element 13, and is transmitted through the transparent resin layer 15. The light then reaches the light diffusing plate 16, and in this case as well, the light diffusing plate 16 is illuminated. Such illumination of the light diffusing plate 16 is performed by each LED element 13, and thus substantially uniform illumination of the light diffusing plate 16 is obtained.

〔Effect of the invention〕

As described above, according to the present invention, a plate material such as a printed circuit board whose upper surface is colored white by printing or the like, and a L
A plurality of LED elements configured by forming a white reflective part on the upper surface of the chip LED in which ED chips are arranged and molded with transparent resin, and a frame-shaped lamp house attached along the periphery of the upper surface of the plate material. , a transparent resin layer filled and cured so as to leave a space above the inner space of the lamp house, and a light diffusing plate stuck on the lamp house so as to cover the entirety of the LED. Since the surface light source device has been constructed, the white reflective part that should be placed above the LED chip is formed integrally with the front plate, so the white reflective part must be repositioned with respect to the LED chip. In addition, since there is nothing that obstructs the flow of the transparent resin during tsukusou molding, the transparent resin can flow well within the predetermined range, and the inner surface of the frame-shaped lamp house. Since the inner surface does not have a stepped portion as in the conventional case and is formed only as a reflective surface, the inner surface can provide extremely good reflection efficiency.

Further, according to the present invention, since a transparent sheet is not required as in the conventional case, the manufacturing process is simplified and costs are reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an embodiment of an LED surface light source device according to the present invention, and FIG. 2 is an enlarged sectional view showing a part of the embodiment of FIG. 1. FIG. 3 is a sectional view showing an example of a conventional LED surface light source device. 1l---LED surface light source device; 12-plate material; 13-LED element; 13a-chip substrate; 13b-LED chip; 13c--solid gold wire;
13d - Transparent resin part; 13e - White reflective part; 1
4- Frame lamp house; 15- Transparent resin layer; 16
− Light diffuser. Patent applicant: Stanley Electric Co., Ltd. Representative: Patent attorney Hirayama - Office

Claims (1)

[Claims] A board material such as a printed circuit board whose upper surface is white by printing etc., and a chip LED which is arranged on the upper surface of the board material at an appropriate interval, and in which LED chips are placed on the chip board in advance and resin molded with transparent resin. a plurality of LED elements each having a white reflective portion formed on the top surface; a frame-shaped lamp house attached along the periphery of the top surface of the plate;
A transparent resin layer filled and cured so as to leave a space above the inner space of the lamp house, and a light diffusing plate attached to the lamp house so as to cover the entire lamp house. An LED surface light source device characterized by: