JP2000114605A - Led display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED display in which a display image can be prevented from being deteriorated by effectively reducing total reflection without any reflection from the surface even when sunlights or illumination lights or the like are made incident. SOLUTION: LED lamps 2 arranged in a frame-shaped case are sealed by water-proof sealing resin 5 in an LED display. Then, surface cracks constituted of fine recession are formed on the surface of a ground 5a of the sealing resin 5 by a blast treatment so that the gross of the surface of the ground 5a can be prevented, and when external lights are made incident, those external lights can be turned into scattered lights by the surface cracks. Thus, the generation of total reflection can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in which a large number of LED lamps each having a light emitting element sealed with a resin are arranged in a matrix, and more particularly to a display device which reflects reflection of a display surface when exposed to sunlight or illumination light. The present invention relates to an LED display capable of obtaining a clear image while suppressing the same.

[0002]

2. Description of the Related Art Image displays using light-emitting diodes (LEDs) have spread from large displays for, for example, outdoor advertisements and traffic displays, to indicators for various traffic lights, automobiles, and televisions. Such image displays are, for example, R (red), G
A plurality of display devices in which three types of LEDs (green) and B (blue) are grouped and arranged in a matrix with one dot as a dot are arranged and arranged so that a full-color image can be obtained as a whole as a screen.

FIG. 7 is a schematic perspective view showing an example in which four LED displays are arranged. In the LED display, R, G, and B LED lamps 22 are arranged in a frame-shaped case 21 in a uniform pattern together with its wiring board and the like. Is sealed.

In general, a case 21 of an LED display is integrally provided with a hood 21b which is located above the horizontally arranged LED lamps 22 and protrudes forward. The hood 21b can prevent the sunlight or illumination light from directly shining on the LED lamp 22 to some extent. Further, it is important that the resin material of the sealing resin 21a has high waterproofness to the LED lamp 22 and has weather resistance, and has a contrast with a displayed image and a color that does not impair the image. In general, a waterproof resin such as silicone or urethane, which is colored in black, is used.

[0005]

However, a resin such as silicone or urethane has a glossy surface after curing, and the sunlight or illumination light impinging on the surface is reflected as it is. In the case of an LED display, the sealing resin 2
In the LED lamp 22 sealed by 1a, a plurality of combined dots are distributed at intervals as shown in FIG.
The surface of a is a reflection surface. Therefore, LED lamp 2
The reflected light comes to appear in the display image by the two dots, which impairs the display image.

If the portion other than the position where the LED lamp 22 is incorporated and the hood 21b is provided are a uniform flat surface, the surface is totally reflected due to the gloss of the surface depending on the incident angle of sunlight or illumination light. Such total reflection causes the surface of the sealing resin 21a to appear white and shiny even when the sealing resin 21a is black, and significantly lowers the contrast with the image by the LED lamp 22. Therefore, the displayed image is difficult to see, and in the case of a color image, it greatly affects the color.

As described above, in the conventional LED display, the resin material of the sealing resin 21a is limited to a resin material which is preferable in terms of waterproofness and weather resistance and which can enhance the contrast with the displayed image. When a resin such as silicone or urethane that satisfies such conditions and has good moldability is used, there is a problem that the external gloss is reflected by the gloss of the surface to affect the image quality.

The problem to be solved in the present invention is that there is no reflection from the surface even when sunlight or illuminating light enters, so that the total reflection is effectively suppressed and the display image is not degraded.
An ED display is provided.

[0009]

The present invention provides a frame-shaped case, an LED board housed in the case, and an LE.
An LED lamp conductively fixed to a D substrate; and a sealing resin of a waterproof synthetic resin injected into the case and sealing the LED substrate and a base end of a resin head of the LED lamp. It is characterized in that a minute uneven surface is formed on the surface of the resin fabric to reflect incident external light as scattered light.

In such a configuration, even if the surface of the sealing resin of the LED display is irradiated with sunlight or illumination light, it is reflected as scattered light by the minute uneven surface, and total reflection is eliminated. In addition, even if the resin material of the sealing resin has glossiness, the glossiness is eliminated by the minute uneven surface, and reflection with high luminance is suppressed.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 is characterized in that a frame-shaped case, an LED board housed in the case, an LED lamp conductively fixed to the LED board, An LED substrate and a sealing resin of a waterproof synthetic resin for sealing including a base end portion of a resin head of the LED lamp, and reflecting external light incident on a cloth surface of the sealing resin as scattered light. It is an LED display having a minute uneven surface, and has an effect of suppressing total reflection from the surface of the sealing resin even when exposed to external light.

According to a second aspect of the present invention, the uneven surface is
2. The LED display according to claim 1, wherein said LED display is formed by a blast process of forming a concave surface flaw on the surface of said encapsulating resin by colliding fine particles. Has the effect that an uneven surface optimal for irregularly reflecting light can be easily obtained.

According to a third aspect of the present invention, the uneven surface is
2. The LED display according to claim 1, wherein minute glass beads are substantially uniformly dispersed and formed on the surface of the sealing resin, and incident light is irregularly reflected by adjusting the size of the glass beads. Has the effect that an optimum uneven surface can be easily obtained.

According to a fourth aspect of the present invention, there is provided the LED according to the first aspect, wherein the resin material of the sealing resin is a heat-curable type, and the uneven surface is formed by press molding at the time of curing the sealing resin. For example, when using a sheet with a mesh formed by press forming, the roughness of the uneven surface can be adjusted according to the size of the mesh, and the optimum uneven surface for diffusely reflecting incident light can be easily obtained. Having.

Hereinafter, specific examples of the embodiments of the present invention will be described with reference to the drawings. The basic structure of the LED display according to the present invention is almost the same as that of the conventional example shown in FIG. 7 except for the processing on the surface thereof. FIG. 1 schematically shows the steps up to the injection of the sealing resin.

In FIG. 1 (a), an LED lamp 2 is conductively fixed to the front side of an LED substrate 1 which is insulative and has a conductive pattern formed on its surface, and a connector pin 3 penetrating to the back side is integrally formed. Is becoming The LED lamp 2 includes a bifurcated lead frame 2 as conventionally known.
a, a light emitting element mounted thereon, and a resin head 2b for sealing the light emitting element.
The ED substrate 1 is electrically connected to the conductor pattern and is fixed by a mold resin.

The LED board 1 integrally provided with the LED lamp 2 and the connector pins 3 is positioned in a case 4 as shown in FIG. This case 4 is a frame-like body having a peripheral wall and a bottom surface excluding a part of the main body 21 of the LED display shown in the conventional example of FIG. 7 and is manufactured separately from the LED substrate 1 in advance. It is.

Next, as shown in FIG. 1C, a thermosetting sealing resin 5 is injected into the case 4. The sealing resin 5 is made of a black resin such as silicone or urethane, and the lead frame 2 on the front side of the LED substrate 1 is left except for the tip side of the resin head 2b of the LED lamp 2.
a and the entirety of the connector pins 3 are sealed. Then, after the sealing resin 5 is cured, the lower ends of the connector pins 3 are electrically connected to the circuit board 6 as shown in FIG. 1D, whereby an LED display is obtained.

In the case where the surface of the sealing resin 5 is uniformly smooth without being subjected to any special processing in the process from injection of the sealing resin 5 to hardening, as described in the prior art, The gloss of the surface of the resin 5 causes total reflection of sunlight and illumination light.

On the other hand, if minute flaws are formed on the surface of the sealing resin 5, the gloss of the surface can be eliminated, thereby suppressing total reflection. Blasting is one effective means for attaching such minute flaws to the surface of the sealing resin 5.

As shown in FIG. 2, this blasting process is performed by, for example, nylon, walnut powder,
The hard fine particles 11a such as a cone are sprayed on the surface of the cured sealing resin 5. The particle size of the particles 11a used for the blasting process is about 150 to 500 μm, and fine flaws having a size and a depth corresponding to the particle size can be uniformly spread on the surface of the sealing resin 5. Note that the resin head 2b of the LED lamp 2 protrudes from the surface of the cloth 5a of the sealing resin 5 and the particles 11a also hit the resin head 2b. No scratches.

FIG. 3 shows the sealing resin 5 after blasting.
1A is a partial perspective view, and FIG. 2B is an enlarged vertical sectional view of a main part.

Particles 11a from the blast nozzle 11 randomly collide with the surface of the cloth 5a of the sealing resin 5, and countless minute recesses 5b are formed as shown in FIG. It becomes a flaw, and a pattern due to the dent 5b appears as shown in FIG. By forming the countless dents 5b on the surface in this way, the surface of the fabric 5a has countless minute uneven surface flaws, and the surface has no gloss.

Therefore, first, the surface of the cloth 5a of the sealing resin 5 loses its luster, so that even if light is applied, a curved portion such as the base of the hood 21b in the conventional example has a linear shape. It will not look shiny. Also, due to the distribution of minute irregularities on the entire surface of the cloth 5a, light incident on the surface is reflected as scattered light from the surface of the recess 5b as shown by the arrow in FIG. 3B. That is, when the surface of the cloth 5a is smooth and glossy, the light is totally reflected and shines whitish, but the total reflection can be eliminated by scattering the reflected light.

As described above, by forming the fine dents 5b as surface flaws on the surface of the cloth 5a of the sealing resin 5 by blasting, total reflection does not occur even when exposed to sunlight or illumination light, and the gloss of the cloth 5a is reduced. Since it is erased from the surface, there is no partial reflection of high brightness. Therefore, high image quality is maintained without the reflected light interfering with the display image generated by the emission of the LED lamp 2, and the contrast between the display image and the black surface color of the sealing resin 5 of the LED display is also impaired. Never be.

FIG. 4 shows an example in which glass beads are mixed into the sealing resin 5 and the glass beads are exposed on the surface of the cloth 5a to have irregularities on the surface and reflect as scattered light. FIG.

In FIG. 4A, a heat-curable resin material 7 such as silicone or urethane prepared as a material is poured into a container 12 and white glass or the like having a particle size of about 0.3 mm. An appropriate amount of the beads 8 is charged, and the glass beads 8 are uniformly distributed in the resin material 7 by the stirring blade 12a. The glass beads 8 are applied, for example, for use as a section of a road surface, and are used to reflect light from a vehicle light so that the section can be easily recognized. In the present invention, silicone or urethane is used. Any resin may be used as long as the specific gravity is smaller than that of the resin.

Next, the resin material 7 and the glass beads 8 are mixed and defoamed, cut out from the container 12, poured into the case 4, and left at room temperature for a certain period of time. During this standing, the specific gravity of the glass beads 8 is smaller,
As shown in (b) of FIG.
Rises to the liquid side of the Then, the resin material 7 is heated and cured in the case 4 in a state where most of the glass beads 8 are collected on the liquid surface.

When the resin material 7 is hardened in the case 4 to form the sealing resin 5, the glass beads 8 appear as fine clusters on the surface of the cloth 5a of the sealing resin 5 as shown in FIG. Some of these glass beads 8 are exposed from the surface of the fabric 5a.

As described above, when the fine glass beads 8 are distributed on the surface of the cloth 5a of the sealing resin 5, minute irregularities are formed by the surface of the cloth 5a and the glass beads 8 which are slightly protruded or depressed from the surface. A pattern appears. Therefore, as in the case of the blast processing shown in FIG. 3, the incident light is reflected as scattered light due to the unevenness of the surface, and total reflection does not occur. Although the glass beads 8 themselves seem to reflect light when they receive the light, the amount of reflection increases instead. However, the particle size of the glass beads 8 is small, the amount of reflected light is small, and the reflection amount is smaller than the surface gloss of the resin. Light is kept low.

FIG. 5 shows still another example. Before the resin material of the sealing resin 5 is poured into the case 4 and cured, a sheet for forming an uneven surface is placed on the surface of the resin material, and the resin surface is glossed. FIG. 4 is a schematic view of a process of obtaining fine irregularities while eliminating the.

FIG. 5A shows a sheet 13 for forming an uneven surface.
It is a schematic perspective view of. This sheet 13 is made of, for example, a net material made of synthetic resin. A fine mesh-like mesh 13a is formed on the entire surface, and an opening 13b for passing the resin head 2b of the LED lamp 2 is opened at a predetermined position. Things.

On the other hand, as in the previous example, a heat-curable resin material 9 is poured into the case 4 and, before the resin material 9 is cured, the sheet 13 is covered and gently pressed against the surface of the resin material 9. . Thereby, the mesh 13a of the sheet 13
A pattern corresponding to the mesh of the mesh is made on the surface of the resin material 9,
The resin material 9 is cured while the mesh pattern is formed. Then, after the resin material 9 is cured, the resin material 9 is integrated with the case 4 to become the sealing resin 5 as shown in (c) of the same figure. One in which the mesh-like unevenness 5c is uniformly transferred is obtained.

As described above, the mesh-like unevenness 5 is formed on the surface of the cloth 5a.
By transferring c, gloss can be eliminated from the surface of the cloth 5a of the sealing resin 5, as in the case of the blast processing of the previous example, and the shining of reflected light is suppressed and total reflection does not occur.

FIG. 6 shows an example in which a fine uneven pattern can be formed on the surface of the cloth 5a of the sealing resin 5 by using the molding die 14 which is the upper die for the case 4.

In FIG. 6, the molding die 14 has L
A concave portion 14a for receiving the resin head 2b of the ED lamp 2 is formed, and the entire lower end surface excluding the concave portion 14a is a minute uneven surface 14b. Then, similarly to the formation of the mesh-like unevenness 5c using the sheet 13 of FIG. 5, the molding die 14 is put on the surface of the resin material and cured before the resin material cures, thereby coping with the uneven surface 14b. Fine irregularities can be formed on the surface of the sealing resin 5.

[0037]

According to the present invention, a minute light is applied to the surface of an encapsulating resin of an LED display device made of a waterproof synthetic resin so that when external light is applied, the light is irregularly reflected and reflected as scattered light. Because of the uneven surface, there is no reflection due to surface gloss, and total reflection can be suppressed even when exposed to sunlight or illumination light. Therefore, the display image does not become difficult to see or the contrast does not decrease due to the reflected light. Further, since the reflected light is not emitted in the form of a spot from the display image, the reflected light does not interfere with the display image, and a high-quality image is maintained.

[Brief description of the drawings]

FIG. 1 is a schematic view sequentially showing a process in which an LED lamp held on an LED substrate is housed in a case and sealed with a sealing resin.

FIG. 2 is a schematic view of an example in which particles are applied to the surface of a sealing resin and blasting is performed.

3A is a schematic perspective view showing the surface of a cloth of a sealing resin obtained by the blast processing of FIG. 2; FIG. 3B is an enlarged cross-sectional view of the cloth surface;

FIG. 4 is a schematic view sequentially showing steps of an example in which glass beads are mixed into a resin to give irregularities to the surface of a cloth.

FIG. 5 is a schematic view sequentially showing steps of an example in which a mesh surface of a sealing resin is used to provide mesh-like irregularities using a mesh of a sheet.

FIG. 6 is a schematic view showing an example in which minute irregularities are formed on the cloth surface of the sealing resin by the irregular surface of the mold.

FIG. 7 shows a conventional LE having no surface treatment of a sealing resin.
A perspective view showing an example in which four D displays are combined.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED board 2 LED lamp 2a Lead frame 2b Resin head 3 Connector pin 4 Case 5 Sealing resin 5a Fabric 5b Depression 5c Mesh-like unevenness 6 Circuit board 7 Resin material 8 Glass beads 9 Resin material 11 Nozzle 11a Particle 12 Container 12a Stirrer blade 13 Sheet 13a Mesh 13b Opening 14 Mold 14a Recess 14b Uneven surface

Claims (4)

[Claims] 1. A frame-shaped case, an LED board housed in the case, and an LE conductively fixed to the LED board.
D lamp, comprising a sealing resin of a waterproof synthetic resin that is injected into the case and seals the LED substrate and the base end of the resin head of the LED lamp, and on a cloth surface of the sealing resin, An LED display having a minute uneven surface that reflects incident external light as scattered light. 2. The LED display according to claim 1, wherein the uneven surface is formed by a blast process of forming a concave surface flaw on the surface of the sealing resin by colliding fine particles. 3. The LED display according to claim 1, wherein the uneven surface is formed by dispersing minute glass beads almost uniformly on the surface of the sealing resin. 4. The LED display according to claim 1, wherein the resin material of the sealing resin is a heat-curable resin material, and the uneven surface is formed by press molding when the sealing resin is cured.