JPH10161569A - Led dot matrix light emitting display body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of display clarity and to improve the heat radiation by arranging the masking plate, in which the opening hole having a radius that is slightly larger than the lamp radius of LED lamps and a space is provided in the lower section peripheral of the hole, on a wiring substrate. SOLUTION: A masking plate 3 is mounted on a wiring substrate 2. The plate 3 is a plastic plate having the size approximately equal to the size of the substrate 2 and has an optically no reflection color (a black color system). Opening holes 3a are formed at the arranged positions of LED lamps 1 on the substrate 2. Each of the holes 3a is a through-hole having the radius which is slightly larger than the radius of the lamps 1. When the plate 3 is mounted on the plate 2, the bottom surfaces of mounting protrusions 3b and positioning protrusions 3c are abutted against the surface of the substrate 2 and the plate 3 itself is arranged with a gap between the substrate 2. Note that a space 5 is provided between the substrate 2 and the plate 3 having the size which is equivalent to the length of the protrusions 3b and 3c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED dot matrix light emitting display in which a large number of LED lamps are mounted on a wiring board both vertically and horizontally.

[0002]

2. Description of the Related Art As shown in FIG.
An LED chip 1b is arranged and wired on the upper ends of two lead frames 1a, 1a, and the periphery of the LED chip 1b is molded and sealed with a translucent epoxy resin 1c. The LED lamp 1 may constitute a light emitting display surface of an LED dot matrix light emitting display by mounting a large number of LED lamps 1 vertically and horizontally on a wiring board (for example, mounting 16 × 16 LEDs). This LED dot matrix light emitting display is connected to a driving device (driver) not shown,
The lighting control device selectively controls the lighting of the LED lamp to display desired characters, figures, and the like, and is mainly used for a signboard or the like in a bright outdoor place. As for such a conventional LED dot matrix light emitting display, each LED lamp 1 is already LE except for a high-density type (one having a dot aperture ratio exceeding 30%) which emphasizes display expression.
Since the D chip 1b is resin-sealed, these LED lamps 1 are simply mounted on a wiring substrate whose surface has a non-reflective color of light (black).

One of the factors that determine the display contrast of the light emitting display surface of the LED dot matrix light emitting display is a dot aperture ratio. This dot aperture ratio is
It is defined by the ratio of the total area of each light emitting region to the total area of the light emitting display surface. In the case of the light emitting display as shown in FIG. 8, the area of the lamp diameter (light emitting area R) of each LED lamp 1 mounted on the wiring board 2 emits light as a light emitting dot and emits light. The black area C between these LED lamps 1 is an area separating each light emitting dot. Since the dot pitch of the light emitting display is (R + C) both vertically and horizontally, the dot aperture ratio is represented by the following equation (1).

(Equation 1)

At this time, the outer peripheral portion (that is, the light emitting area) of each LED lamp reflects light incident from the outer surface and causes a reduction in display contrast of the light emitting display surface. As the dot aperture ratio increases, the amount of external light reflection increases, causing a reduction in display contrast. That is, the smaller the dot aperture ratio, the larger the black region C with respect to the light emitting region R on the light emitting display surface, so that the contrast of the light emitting display surface display is improved and the display clarity is improved. In addition, this tendency becomes more remarkable in a brighter place.

[0005]

However, the light emitting region R corresponds to the lamp diameter of the LED lamp 1 and the black region C
Corresponds to the distance between each LED lamp 1 is the LED
When the dot matrix light-emitting display body is viewed from the front, as shown in FIG. 9, when the light-emitting display body is viewed from an oblique direction (viewing angle θ), the area between the LED lamps 1 is reduced. Most are hidden behind the LED lamp 1 on the near side, so that the black area Cs is extremely narrow. Moreover, since the LED lamp 1 generally has a vertically long shape, the black area Cs is further narrowed. In addition, LED
When the lamp 1 has such a vertically long shape, the LED lamp 1 can be seen to the side surface when the viewing angle θ is oblique, so that the light emitting region Rs is widened.

For this reason, the conventional LED dot matrix light emitting display has a black area Cs when viewed from an oblique direction.
And the light emitting region Rs is widened, so that the apparent dot aperture ratio is increased, and the contrast of the light emitting display surface is deteriorated, and the display clarity is reduced.

In view of the above circumstances, the present invention can prevent a decrease in display clarity of a light emitting display surface when viewed from an oblique direction by disposing a mask plate on a wiring board on which an LED lamp is mounted. LED with good heat dissipation
An object is to provide a dot matrix light emitting display.

[0008]

In order to solve the above-mentioned problems, the present invention is directed to an LED dot matrix light-emitting display device in which a large number of LED lamps are mounted vertically and horizontally on a wiring board to form a light-emitting display surface. The surface of the LED lamp has a black non-reflective color, and at the mounting position of each LED lamp, an opening having a diameter slightly larger than the lamp diameter of the LED lamp is provided, and at least a space is provided around a lower portion of the opening. The obtained mask plate is arranged on a wiring board.

According to the first aspect of the present invention, since the surface of the mask plate disposed at a position higher than the surface of the wiring board in the non-reflective color is a black region separating light emitting dots, the mask plate is viewed from an oblique direction. In this case, the shaded portion of the LED lamp on the near side is reduced. In addition, since the side surfaces of the LED lamps are accommodated in the opening holes of the mask plate, the light emitting region hardly expands when viewed from an oblique direction. Therefore, since the apparent dot aperture ratio does not become too large, the display contrast of the light emitting display surface does not deteriorate. In addition, a space is provided around the lower part of each opening of the mask plate, and convection ventilation with the outside air is sufficiently performed, so that heat of each LED lamp can be effectively released.

According to a second aspect of the present invention, the mask plate is mounted on the wiring board via a projection projecting from the back surface, and a space corresponding to the length of the projection is provided between the mask plate and the wiring board. It is characterized by having been done.

According to the second aspect of the present invention, since a wide space is formed between the mask plate and the wiring board below the opening, the heat radiation of each LED lamp can be more effectively performed. become.

According to a third aspect of the present invention, there is provided a method as described above, wherein the surface of the mask plate is moved up and down with respect to the top of the LED lamp mounted on the wiring board by a height of less than half the lamp diameter of the LED lamp. It is characterized by being arranged in.

According to the third aspect of the present invention, since the surface of the mask plate is at substantially the same height as the top of the LED lamp mounted on the wiring board, the light emission display is performed because the surface of the mask plate is too low. Deterioration of the display contrast on the surface cannot be effectively prevented, and the display becomes difficult to see from an oblique direction because the surface of the mask plate is too high.

According to a fourth aspect of the present invention, the dot aperture ratio of the light emitting display surface is set to 10% or less.

According to the fourth aspect of the present invention, it is most suitable for use in installation in bright surroundings such as outdoors during the daytime, and the light emission by the lamp diameter of the LED lamp is smaller than the black area on the surface of the mask plate. The area is extremely narrow, and therefore, it is very easy to ensure a relative luminance difference between the emission luminance of the invention area and the surrounding brightness, and the display contrast of the light emitting display surface particularly in a bright surrounding area by the use of the mask plate. Can be effectively and effectively prevented from deteriorating.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 6 show an embodiment of the present invention. FIG. 1 is a partial longitudinal sectional view of a light emitting display taken along line AA in FIG. 3, and FIG. 2 is a wiring board and a mask plate. FIG. 3 is a partial plan view of a light emitting display body, FIG. 4 is a partially enlarged longitudinal sectional view showing a relationship between a top of an LED lamp and a height position of a surface of a mask plate, and FIG. FIG. 6 is a partially enlarged longitudinal sectional view showing another example of the mask plate, and FIG. 6 is a partially enlarged longitudinal sectional view showing still another example of the mask plate. In addition, FIG.
Components having functions similar to those of the conventional example shown in FIG. 9 are denoted by the same reference numerals.

As shown in FIG. 2, the LED dot matrix light emitting display of the present embodiment has a large number of LED lamps 1.
Are mounted on the wiring board 2 by arranging them vertically and horizontally. That is, as shown in FIG. 1, each LED lamp 1 has two lead frames 1a, 1
a, and these lead frames 1a, 1a
Are arranged and wired by soldering. Also, each L
As shown in FIG. 3, the ED lamps 1 are arranged in a matrix at the same dot pitch in the vertical and horizontal directions, are connected to a driving device (driver) (not shown), and selectively control the lighting of the LED lamps 1 by the lighting control device. , Desired characters and figures are displayed. In this embodiment, the lamp diameter of the LED lamp 1 is φ3 mm, and the dot pitch is 15 m.
The case where the dot aperture ratio is 3.14% is shown as m.

A mask plate 3 is mounted on the wiring board 2. The mask plate 3 is a light non-reflective (black) plastic plate having substantially the same size as the wiring board 2, and has openings 3 a at the positions where the LED lamps 1 are arranged on the wiring board 2. . Each opening 3 a is a through hole having a diameter slightly larger than the lamp diameter of the LED lamp 1. On the back surface of the mask plate 3, a pipe-shaped mounting protrusion 3b and a rod-shaped positioning protrusion 3c having the same length are fixed downward at appropriate positions between the opening holes 3a. These mounting projections 3b
Alternatively, the sum of the lengths of the positioning projections 3c is made to match the height of the LED lamp 1. Therefore, when the mask plate 3 is placed on the wiring board 2, the mounting projections 3
b and the bottom surface of the positioning protrusion 3 c abut on the surface of the wiring board 2, and the mask plate 3 itself is arranged with a gap between itself and the wiring board 2. The upper part of each LED lamp 1 is fitted into the opening 3a of the mask plate 3, and the top is
At the same height as the surface. A screw hole 2a is previously opened in the wiring board 2 at a contact portion of the mounting projection 3b. Thereby, the mask plate 3 is attached and fixed on the wiring board 2.

With the above configuration, as shown in FIG.
Since the surface of the black mask plate 3 at the same height as the top of the D lamp 1 becomes a black area C separating each light emitting dot, a black area Cs when the light emitting display is viewed from an oblique direction.
However, it is no longer possible to become narrow behind the LED lamp 1 on the near side. Further, only the upper part of the LED lamp 1 that can be seen through the opening 3a of the mask plate 3 is a light emitting region R, and the side surface of the LED lamp 1 is shielded by the mask plate 3, so that the light emitting region Rs when viewed from an oblique direction. Will not spread. In addition, between the wiring board 2 and the mask plate 3, the mounting projection 3b and the positioning projection 3
Since there is a space 5 for the length of c, since the structure is such that air convection (ventilation) with the outside air is sufficiently performed, heat radiation from the side surface of each LED lamp 1 to the outside air is not obstructed. Thus, overheating of these LED lamps 1 can be prevented.

Therefore, according to the LED dot matrix light emitting display of the present embodiment, the ratio of the black area Cs to the light emitting area Rs when viewed from the oblique direction is different from the black area C and the light emitting area R when viewed from the front. , So that the apparent dot aperture ratio when viewed from an oblique direction is hardly increased, the contrast of the light-emitting display surface is kept good from any viewing position, and the deterioration of display clarity is prevented. be able to. In addition, the heat generated when the LED lamps 1 are turned on causes sufficient air convection (ventilation) with the outside air in the peripheral side surface of each LED lamp 1 and in the space 5 between the wiring board 2 and the mask plate 3. Because of this structure, heat radiation is extremely good, and there is no danger that heat will be trapped in the opening 3a of the mask plate 3 and overheated.

In the above embodiment, the surface of the mask plate 3 is L
Although the case where the height is the same as the top of the ED lamp 1 has been described, as shown in FIG.
The lamp 1 may be arranged at a position slightly higher and lower than the top. However, if the surface of the mask plate 3 is too low,
The protrusion of the LED lamp 1 is too high, and the black area Cs
Becomes narrower and the light emitting region Rs becomes wider, so that deterioration of contrast cannot be effectively prevented. Also, the mask plate 3
If the surface of the LED lamp 1 is too high, the LED lamp 1
Since only the light emitting region Rs is narrowed due to being retracted into a, it is difficult to see from an oblique direction. Therefore, this mask plate 3
When the displacement from the height of the top of the LED lamp 1 is ± L and the lamp diameter of the LED lamp 1 is D,
L <D / 2, preferably L <D
Those in the range of about / 3 are practical. The height position of the surface of the mask plate 3 can be easily adjusted by the length of the mounting projection 3b and the positioning projection 3c according to a desired viewing angle.

In the embodiment, as a preferable example,
By mounting the mask plate 3 by floating it from the wiring board 2 by the mounting projections 3b and the positioning projections 3c,
A space 5 is formed between the wiring board 2 and the mask plate 3,
The heat generated by the LED lamp 1 is effectively released into the outside air. However, at least the opening 3a of the mask plate 3
If a space 5 is provided around the lower portion of the LED lamp 1, heat can be radiated to the outside air by air convection in the peripheral portion of each LED lamp 1, so that the thick mask plate 3 is directly fixed on the wiring board 2, For example, as shown in FIG. 5, the space 3 is provided in the lower part by making the opening 3a into an inverted mortar shape having a larger diameter toward the lower side, or the diameter below the opening 3a is made larger as shown in FIG. By doing so, the space 5 may be provided in the lower part.

In the above embodiment, an LED dot matrix light emitting display having a dot aperture ratio of 3.14% has been described. However, if the dot aperture ratio is too large, the original black area C becomes narrower, so As a result, the amount of external light reflected on the light-emitting display surface increases, and the display contrast deteriorates, so that it is difficult to sufficiently exert the effects of the present invention. In particular, this tendency increases when it is installed and used in a bright place such as outdoors. Therefore, the dot aperture ratio is suitably 10% or less, and preferably about 6 to 2.5% is practical. That is, by reducing the dot aperture ratio, it is easy to increase the light emission luminance in each light emitting region, and it is possible to reduce the amount of external light reflected on the light emitting display surface. It is less affected by brightness. On the other hand, if the dot aperture ratio is too small (2.5% or less), the display expression deteriorates. For example, as a specific example, when the lamp diameter of the LED lamp 1 is φ3 mm, if the dot pitch is about 10 to 20 mm, the dot aperture ratio is 7.1 to 1.8%, and the lamp diameter is φ5 m.
In the case of m, if the dot pitch is about 15 to 30 mm, the dot aperture ratio is 8.7 to 2.2%.

In this embodiment, the mask plate 3 is formed of a black plastic plate. However, it is sufficient that at least the surface of the mask plate 3 does not reflect light as much as possible. Can be used after being subjected to black coating or surface treatment.

Further, in the present embodiment, the case where one LED lamp 1 is mounted for each dot with the same vertical and horizontal dot pitch has been exemplified, but the case where the dot pitch differs in the vertical and horizontal directions may be used. It goes without saying that a plurality of LED lamps 1 having different emission colors may be mounted to form emission dots.

[0027]

As is evident from the above description, according to the LED dot matrix light emitting display of the present invention, the black area separating the light emitting dots greatly depends on the viewing position, such as when viewed from an oblique direction. Since the light-emitting area does not become narrow and does not greatly expand, the display contrast of the light-emitting display surface can be maintained satisfactorily without being affected by the viewing position, and a decrease in display clarity can be prevented. Moreover, each L
In the ED lamp, convection (ventilation) with the outside air is sufficiently performed by the space around the lower part of the opening, and heat can be effectively radiated into the outside air. There is no fear. Further, by setting the dot aperture ratio to 10% or less, the display contrast can be kept good regardless of the surrounding brightness, and the display clarity can be kept.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and FIG.
FIG. 2 is a partial vertical cross-sectional view of the light emitting display body taken along line AA of FIG.

FIG. 2, showing an embodiment of the present invention, is a perspective view illustrating a state before a wiring board and a mask plate are attached.

FIG. 3, showing an embodiment of the present invention, is a partial plan view of a light emitting display.

FIG. 4 illustrates an embodiment of the present invention, wherein LE is
FIG. 4 is a partially enlarged longitudinal sectional view illustrating a relationship between a top portion of a D lamp and a height position of a surface of a mask plate.

FIG. 5, showing an embodiment of the present invention, is a partially enlarged longitudinal sectional view showing another example of a mask plate.

FIG. 6 shows an embodiment of the present invention, and is a partially enlarged longitudinal sectional view showing still another example of the mask plate.

FIG. 7 is a longitudinal sectional view showing the structure of the LED lamp.

FIG. 8 shows a conventional example, and is a partial longitudinal sectional view of a light emitting display.

FIG. 9 shows a conventional example, and is a partial vertical cross-sectional view of a light emitting display when viewed obliquely.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED lamp 2 Wiring board 3 Mask board 3a Opening hole 5 Space

Claims (4)

[Claims] 1. An LED dot matrix light-emitting display device comprising a plurality of LED lamps mounted on a wiring board vertically and horizontally to form a light-emitting display surface, wherein the surface is a black non-reflective color, and the mounting position of each LED lamp An LED dot matrix having an opening having a diameter slightly larger than the lamp diameter of the LED lamp, and a mask plate provided with a space at least around a lower portion of the opening on a wiring board. Luminescent display. 2. The method according to claim 1, wherein the mask plate is mounted on a wiring board via a projection protruding from a rear surface, and a space corresponding to the length of the projection is provided between the mask plate and the wiring board. The LED dot matrix light emitting display according to claim 1, wherein: 3. The mask plate according to claim 1, wherein the surface of the mask plate is disposed at a position lower and higher than the top of the LED lamp mounted on the wiring board by a height of less than half the lamp diameter of the LED lamp. The LED dot matrix light emitting display according to claim 1 or 2, wherein: 4. The LED dot matrix light emitting display according to claim 1, wherein a dot aperture ratio of said light emitting display surface is 10% or less.