JPH0527688A - Dot matrix led unit - Google Patents

Abstract

PURPOSE:To improve the display performance of a dot matrix LED unit for which a measure is taken to stop a LED lamp side direction light leak without using a case. CONSTITUTION:The unit consists of plural dot matrix type light emitting diode lamps 2a, a black color printed board 3 and a printed board 4 on which parts are mounted. In the outer peripheral of the sealing resin section of the light emitting diode lamp 2a, the region, which includes the position higher than a light emitting diode chip 6 location, is covered by a light opaque type material to make a measure against a light leak in the side direction thus, the display visibility is improved and by changing the height, the maximum field of view angle is adjusted. Furthermore, the forward light radiation efficiency is improved by coating a light reflective material on the inside of a light opaque section 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for improving the performance of a dot matrix light emitting diode (hereinafter referred to as LED) unit capable of displaying a plurality of numbers and characters.

[0002]

2. Description of the Related Art Dot matrix LED units are
The display device has a plurality of LED lamps arranged in a dot matrix and displays numbers and characters depending on the shape of the LED lamps that are turned on.

In this display, when the light of the lighted LED lamp is projected on the non-lighted LED lamp, the non-lighted portion also scatters and emits some light, and the recognition of the display pattern becomes poor. , It may be displayed incorrectly. In recent years, in particular, LED units are often used for information display in bright places such as outdoors or in vehicles. Preventing the above-mentioned erroneous display is for easy-to-read display with a high-density dot matrix arrangement. Has become an important issue.

4A and 4B are a front view and a sectional view of a conventional dot matrix LED unit.
Printed circuit board 3 on which a plurality of LED lamps 2 are mounted
And a printed circuit board 4 on which electronic components such as an integrated circuit (IC) and a capacitor are mounted, has a two-layer structure, and each case 1 has a hole having the outer diameter of each LED lamp 2. It is attached to cover the LED lamp 2,
Light was prevented from leaking to the non-lighted dot portion next to the lighting LED lamp 2.

[0005]

The conventional dot matrix LED unit shown in FIG. 4 has the following problems. That is, (1) Different molds for the case 1 are required depending on the shape of the LED lamp 2 used.
(2) Even if the LED lamps 2 having the same size are used, a different mold for the case 1 is required when changing the viewing angle, which increases the cost. (3) It takes time to insert the case 1. (4) There is a problem in that heat is transmitted through the case 1 due to the heat generated by the LED lamp 2, and the LED lamp 2 is thermally deteriorated.

Further, the above problems can be solved by covering the lower outer circumference of the LED lamp encapsulating resin portion with a light opaque material as a method without using a case. As an LED lamp in which the lower region including the outer peripheral portion is non-transparent, a method of packaging the lead region with a dark member (USP
No. 3,609,475), a method of covering the lower outer periphery of the sealing resin portion with a light-impermeable collar (collar member) (USP 3,86).
3,075).

However, any type of LED lamp
The part below the LED chip is dark plastic,
Or it is only covered with color and there is light emission from the side, and it is not possible to eliminate the influence on the adjacent dots.

In view of the above-mentioned problems, the present invention provides a dot matrix LED unit which does not use a case to prevent lateral light leakage of an LED lamp.

[0009]

The invention according to claim 1 comprises a plurality of light emitting diode lamps arranged in a dot matrix, a black or colored printed circuit board, and a printed circuit board on which components are mounted. In the dot-matrix LED unit, the light emitting diode lamp is characterized in that the outer periphery of the sealing resin portion of the light emitting diode lamp is covered with a light impermeable material in a region including a height higher than the position of the light emitting diode chip. To do.

According to a second aspect of the present invention, in the first aspect, the outer peripheral region of the sealing resin portion of the light emitting diode lamp is covered with a light-impermeable material having a light-reflecting inside and a black or colored outside. It is characterized by

[0011]

[Function] The outer periphery of the lower part of the sealing resin portion of the LED lamp is LE
By adopting a structure that uses an LED lamp that covers a region higher than the position of the D chip with a light opaque material, a dot matrix LED unit with good controllability of the viewing angle that does not require a case for light leakage prevention can be realized. Moreover, since the case is not required, it is possible to prevent heat deterioration due to heat generation of the LED lamps arranged in high density.

Further, by using an LED lamp whose coated inner surface is covered with a light-impermeable material having light reflectivity, LE
The efficiency of light emitted from the D chip can be improved.

[0013]

1 (A) and 1 (B) are a front view and a sectional view of an embodiment of a dot matrix LED unit according to the present invention.

That is, the side surface opaque type LED lamp 2a in which the outer periphery of the lower portion of the sealing resin portion is covered with a light opaque material such as black ink.
A black printed circuit board 3 in which dots are arranged in a dot matrix and a printed circuit board 4 on which electronic components such as an integrated circuit (IC) and a capacitor are mounted are connected and fixed by a lead frame 5 of an LED lamp 2a to form a two-layer structure. It is made as follows.

FIG. 2 shows the structure of the LED lamp 2a of the dot matrix LED unit of the embodiment according to the present invention. The LED chip 6 is mounted on the flat lead frame 5a, and the upper edge of the light opaque portion 7 applied to the outer periphery of the sealing resin portion is above the mounting position, and the difference in height is high. Indicated by L. That is, by changing the height L,
The maximum viewing angle can be changed. Even if the LED lamp 2a has a high directivity, it has a relative emission intensity of about 20% in the direction of the radiation angle of 60 degrees. Therefore, as the pitch of the dots is narrower, L is increased and the LED of the adjacent dot due to light leakage in the lateral direction. The effect on the lamp is suppressed and the viewing angle is adjusted.

As described above, by forming the light opaque portion 7 including the region above the mounting position of the LED chip 6,
Similar to the case where there is a conventional case (shown in FIG. 4) by cutting the light leakage to the sealing resin part of the LED lamp 2a of the adjacent dot and using the black printed circuit board 3 as the mounting printed circuit board. A clear display with good contrast was obtained. In this embodiment, the outer diameter is 5φ.
The LED lamps 2a are arranged in a 16 × 16 dot matrix, and Chinese characters and simple pictures can be displayed.

FIGS. 3A and 3B respectively show the height of the light non-transmissive portion 7 applied to two adjacent LED lamps 2a and the state of projected light when the dot pitch is narrow and wide. It is a schematic cross section shown. That is, when the dot pitch is narrow (A), the maximum viewing angle is defined from the mounting portion of the LED chip 6 by the height of the apex of the sealing resin portion and the radius of the hemisphere of the top portion, which corresponds to the maximum viewing angle. The height of the light opaque portion is set at the position to be set. When the dot pitch is wide (B), it means that the range of the maximum viewing angle that can be adjusted by adjusting the height of the light non-transmissive portion is wide.

An LED lamp in which an LED chip is mounted in a dish-shaped reflecting portion at the tip of a lead frame is well known. However, in this case, since the maximum angle of the viewing angle is substantially determined by the shape of the dish-shaped reflecting portion, changing the viewing angle requires changing the mold of the dish-shaped reflecting portion. On the other hand, according to this example, the tip of the lead frame on which the LED chip 6 is mounted may have a flat plate shape, and by changing the area of the coating portion (light opacity 7) of the light opaque material, the maximum viewing angle Easy to change.

In the LED lamp 2a used in this example, the light non-transmissive portion 7 is first coated with white ink,
By applying the black ink for the second time, the light emitted from the LED chip 6 can be efficiently reflected inside, which is effective in increasing the luminous intensity. Alternatively, the reflection efficiency of the radiated light can be similarly increased by using the metallic luster ink (gold or silver) for the first time and the black ink for the second time. Instead of ink, it may be covered with a resin having the same effect. Further, the same effect can be obtained by using a black tape instead of the ink, a metal gloss tape on the inside, and a black tape on the outside.

As another embodiment according to the present invention, the ink (resin) applied to the printed circuit board is an ink having a color other than black, which has a good contrast with the emission color of the LED lamp (for example, a dark blue color with respect to the emission color of yellow). By applying and applying the same color to the ink applied to the sealing resin part, a fashionable dot matrix LED unit can be realized.

[0021]

In the past, every time the type of lamp used was changed, the cost for producing the mold was high and the cost was high. However, a dot matrix LED using an LED lamp that prevents light leakage from the lateral direction is used. By making it a unit,
Since it is not necessary to make a case die, the cost can be reduced.

Further, the viewing angle can be easily changed by changing the width of the light opaque portion covering the sealing resin portion. That is, L
A larger angle makes the viewing angle narrower, and a smaller value makes the viewing angle wider, which enables simple control.

By applying white ink or metallic luster ink to the sealing resin portion for the first time and covering it with black ink for the second time, the light leaking in the lateral direction is reflected and the radiated light is emitted. Can be radiated forward effectively and a sufficient luminous intensity can be obtained.

[Brief description of drawings]

FIG. 1 is a front view (A) and a sectional view (B) showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structural example of an LED lamp of one embodiment.

FIG. 3 is a schematic cross-sectional view for explaining the relationship between the height of an opaque portion of an LED lamp and the maximum viewing angle.

FIG. 4 is a front view (A) and a sectional view (B) showing a conventional example.

[Explanation of symbols]

2a LED lamp 3 printed circuit boards 4 printed circuit boards 6 LED chip 7 Light opaque part

Claims (2)

[Claims] 1. A dot matrix LED unit comprising a plurality of light emitting diode lamps arranged in a dot matrix, a black or colored printed circuit board, and a printed circuit board on which components are mounted. A dot-matrix LED unit characterized in that a portion of the outer periphery of the sealing resin portion of the lamp, which includes the light emitting diode chip at a height or higher, is covered with a light opaque material. 2. The outer peripheral region of the encapsulating resin portion of a light emitting diode lamp according to claim 1, wherein the inner side is light reflective,
The dot matrix LED unit is characterized in that the outside is covered with a black or colored light-impermeable material.