JP4091233B2 - Dot matrix display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dot matrix display device in which light emitting elements are arranged in a matrix and each light emitting element is displayed as one dot. More specifically, even when a light emitting element is mounted with a chip-type LED or a bare LED chip that does not have a reflecting wall around it, the light is condensed on the front side of the display panel and has a particularly strong directivity on the front side. The present invention relates to a dot matrix display device having a structure capable of providing a display device with high luminance.
[0002]
[Prior art]
In the conventional dot matrix display device, for example, a cross-sectional explanatory diagram of an example thereof is shown in FIG. 3A, for example, chip-type light emitting elements (hereinafter referred to as LEDs) 52 are arranged in a matrix on the surface side of the display panel substrate 51. A drive circuit (not shown), a power supply terminal for each LED 52, and the like are provided on the back surface of the display panel substrate 51. By selectively turning on and off the LEDs 52 arranged in a matrix, desired characters and It is configured to display graphics. In addition, a lens case 54 having a semicircular or oval cross-sectional shape may be provided on the front surface side of the LED 52, so that light may be concentrated on the front side to improve luminance. Many display devices are arranged vertically and horizontally and used as a large display board in a public bulletin board or the like.
[0003]
The lens case 54 has a flat bottom surface and can be placed on the LEDs 52 arranged side by side. However, as shown in FIG. 3 (b), a rectangular cavity surrounding the LEDs 52 is formed. There is also a case.
[0004]
[Problems to be solved by the invention]
If the LED 52 used in the above-described dot matrix display device is a chip-type LED having a reflection wall 57 around as shown in FIG. 3A, the light traveling laterally from the LED chip 52a is also reflected. Since the light is reflected upward by the wall 57, the light is condensed by the lens case 54 provided on the upper portion of the wall 57, and strong directivity is obtained. However, when the LED 52 is a chip-type light emitting element that does not have the reflective case 57 or a bare chip with only a chip, the light traveling in the lateral or oblique direction is about 30 to 40% of the total light emission amount, but these lights are Do not enter the convex part of the lens case 54, attenuate it by total reflection, or proceed to the next dot (LED 52), brighten the dot that should not emit light and obstruct the original dot. It does not contribute to the brightness of. Therefore, there is a problem that the luminance cannot be improved sufficiently.
[0005]
Further, as shown in FIG. 3B, even when the LED 52 is covered with the lens case 54, the structure of the cavity around the LED 52 is a combination of vertical surfaces such as a quadrangle, so that the light is sufficiently lensed. Even if it cannot be taken into the case 54 and is taken into the lens case 54, it can only go through the lens case 54 toward the next dot and cannot be fully utilized.
[0006]
The present invention was made to solve such a problem, and even when using a chip-type light emitting element having no reflecting wall or a bare chip LED as it is, it collects as much light as possible on the front side, An object of the present invention is to provide a dot matrix display device that has high brightness on the front side and is less likely to leak light to adjacent dots and is easy to recognize and excellent in display quality.
[0007]
[Means for Solving the Problems]
The dot matrix display device according to the present invention includes a display panel substrate, a plurality of light emitting elements arranged in a matrix on the display panel substrate, and a convex portion formed in correspondence with each of the light emitting elements. A lens case provided on the surface side of the element, and the lens case has a rectangular cavity with a bottom shape capable of enclosing the light emitting element inside the convex part, and on the outer periphery from the cavity. A void portion having a flat inclined surface that reflects light emitted from the light emitting portion in a lateral direction toward the convex portion is formed in a lattice shape at a boundary portion of the plurality of light emitting elements , and the cavity portion The side wall is provided in close contact with the display panel substrate so as to completely cover the periphery of each light emitting element, and the inclined surface is formed to extend from the display panel substrate surface. Parts are in plan view, while larger are formed overlap with so that at least a portion of the inclined surface, and the convex portions for adjacent light-emitting elements are formed so as not connected by the convex portions.
[0008]
With this structure, the lens case covers the light emitting element, the light traveling in the lateral direction is also taken into the lens case, and an inclined surface that reflects the light traveling in the lateral direction in the direction of the convex portion is formed around the lens case. Since the gap portion is formed, the light traveling in the lateral direction can be efficiently reflected to the front side. The gap can be easily formed without increasing the number of steps only by changing the shape of the mold when forming the light-convex convex portion. Therefore, without using an expensive light-emitting element having a reflecting wall as the light-emitting element, the light from the light-emitting element can be used effectively by simply forming a reflective gap in the condensing lens case. Therefore, the light mixed into the adjacent dots can be greatly reduced, and a dot matrix type display device having excellent visual recognition characteristics can be obtained.
[0009]
It is preferable that the side wall of the cavity is formed to be a curved surface or an inclined surface inclined toward the center with respect to the vertical surface of the substrate, so that light from the light emitting element can be easily taken into the lens case.
[0010]
The top surface of the hollow portion is formed to have a curvature larger than the curvature of the flat surface or the convex portion of the lens case, so that light can be easily taken into the lens case and light is emitted from the lens case to the front side. It is preferable because it is easy to do.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, the dot matrix display device of the present invention will be described with reference to the drawings. In the dot matrix display device according to the present invention, as shown in FIGS. 1 (a) to 1 (c), a perspective view and a partial cross-sectional explanatory view of the embodiment, and a view seen from the bottom side of the lens case, A lens case 4 in which the light emitting elements 2 are arranged in a matrix on the display panel substrate 1 and a convex portion 41 is formed so as to coincide with each of the light emitting elements 2 is provided on the surface side of the light emitting element 2. ing. The lens case 4 has a cavity 42 that can enclose the light emitting element 2 inside the convex part 41, and the light emitted from the light emitting element 2 in the lateral direction to the outer periphery from the cavity 42. A gap 44 having an inclined surface 43 to be reflected toward the convex portion 41 is formed. In FIG. 1, reference numeral 5 denotes a mounting plate made of, for example, aluminum.
[0012]
The display panel substrate 1 is made of, for example, an aluminum core substrate, and a wiring pattern (not shown) is formed on the surface thereof. The display panel substrate 1 is connected to each electrode of the light emitting element 2 mounted on the surface. Note that a control circuit for controlling on / off of each light emitting element and a resistance of a driving circuit for driving the light emitting element 2 are provided on the back surface of the display panel substrate 1, but are omitted in the drawing.
[0013]
The light emitting element 2 is provided with terminal electrodes 22 and 23 from both ends of the surface of the insulating substrate 21 to the side surface and the back surface, as shown in FIG. The LED chip 24 is die-bonded on the top. The other electrode of the LED chip 24 and the second terminal electrode 23 are electrically connected by a wire 25 such as a gold wire. Then, the periphery is covered with a transparent epoxy resin or the like, and a package 26 having a flat surface is formed. As shown in this example, the light-emitting element 2 has a chip-type light-emitting element that does not have a reflecting wall or a bare chip that has only an LED chip in a lateral direction than a chip-type light-emitting element that has a reflecting wall or a lamp-type light-emitting element. The effect is great because there is a lot of light traveling and the light can be used effectively. The light emitting element 2 has terminal electrodes 22 and 23 at both ends thereof electrically connected and fixed on the wiring pattern of the display panel substrate 1 by soldering or the like.
[0014]
As shown in FIG. 1A, for example, 16 × 16 or 24 × 24 light emitting elements 2 are attached to one unit. And, for example, when configuring a large display board used for a station destination display or a public bulletin board, a large number of these units are arranged in one column or a plurality of columns, one character is displayed by one unit, A large-sized display board is configured by sequentially changing and displaying a continuous character string, scrolling, or arranging a large number of units vertically and horizontally in a matrix.
[0015]
As shown in the cross-sectional explanatory diagram of FIG. 1B, the lens case 4 has a convex portion 41 at a portion corresponding to the position of the light emitting element 2 on one side of a plate-like body made of, for example, acrylic or polycarbonate. The cavity 42 is formed so that the light emitting element 2 can be included therein. Further, a gap 44 is formed on the outer peripheral side of the cavity 42.
[0016]
The shape of the convex portion 41 is, for example, a spherical shape so as to cover and cover each of the light emitting elements 2, but even if it is not a perfect spherical shape, it is long in the side and elliptical in cross section that is small in the vertical direction. The structure may be sufficient as long as it is substantially symmetrical with respect to the central axis. The convex portion 41 has a function of condensing light to some extent. However, the light is not incident as parallel light, and particularly on the surface of the light emitting element 2 that does not have a reflecting wall, with wide directivity in all directions. Light is radiated, and light entering the convex portion 41 also enters in all directions. Therefore, the light emitted from the convex portion 41 does not completely converge on the central axis and exits in all directions, but does not spread too much outward due to the convex lens effect. Even when observing from above, it is possible to see well.
[0017]
As described above, the cavity 42 is formed on the surface opposite to the surface on which the convex portion 41 of the lens case 4 is formed. The hollow portion 42 includes the light emitting element 2 and has a side wall formed so that light from the light emitting element 2 can be taken in and refracted to the front side as much as possible. That is, since the lens case 4 is refracted when the refractive index of the lens case 4 is about 1.59 and larger than the refractive index 1 of air, the curved surface has a large curvature or is inclined to the center side so as to be easily refracted to the front side. Is formed. As shown in FIG. 1B, the top surface of the cavity 42 may be formed in a substantially planar shape. Further, the shape of the bottom surface may be a structure that can enclose the light emitting element 2, and is formed in a polygon or a circle of four or more squares. FIG. 2 shows an example of the shape of the cavity 42 having a quadrangular bottom surface and a curved side wall. T is the top surface, S is the side wall, and B is the bottom surface.
[0018]
The gap 44 provided around the cavity 42 is emitted from the light emitting element 2 in the lateral direction by utilizing the fact that the refractive index of the lens case 4 is about 1.59 and larger than 1 as described above. The light taken into the lens case 4 is totally reflected and directed toward the front side, and is formed on the front side so as to form an inclined surface 43 that can be easily totally reflected. That is, by forming the inclined surface 43 and the substrate 1 so that the angle θ is, for example, about θ = 60 ° or less, the light incident in the lateral direction can be totally reflected and directed to the front side. it can. The gap 44 is formed between adjacent dots, and a partial bottom view of the lens case 4 when the bottom shape of the cavity 42 is a quadrangular shape is shown in FIG. Gaps 44 are formed in a lattice shape. In FIG. 1C, M indicates the top of the gap, and T, S, and B indicate the same parts as in FIG.
[0019]
Since the lens case 4 can be easily manufactured by pouring acrylic, polycarbonate resin, or the like into a mold, even a complicated shape can be easily manufactured once the mold is manufactured. The lens case 4 may be fixed to the display panel substrate 1 with an adhesive, or a lens case 4 having a structure in which a hook is provided on the lens case 4 to be fixed to the display panel substrate 1 or a cover case provided with a caulking pin (not shown). It is also possible to adopt a structure that is held down from above the case 4 and fixed with caulking pins.
[0020]
According to the dot matrix display device of the present invention, since the gap that reflects the light traveling in the lateral direction to the front side is formed integrally with the lens case that collects the light on the front side, the light emitting element is the reflection wall. In a chip-type light emitting device or bare chip LED that does not have light, the light traveling in the lateral direction is also reflected by the inclined surface that is the boundary surface with the gap, and as shown by the arrow in FIG. Gathers light. As a result, light can be collected on the front side very effectively, and the output efficiency is greatly improved. In addition, since the lens case is integrally molded with a mold, the cost is not increased compared to the conventional lens case, and the dot matrix display has a high luminance while using an inexpensive light emitting element that does not have a reflecting wall. A device is obtained.
[0021]
【The invention's effect】
According to the present invention, it is possible to obtain a dot matrix display device that has a high brightness on the front side and has no light interference between adjacent dots while using a light-emitting element having a simple structure. As a result, it is an inexpensive display device that can firmly recognize public displays such as station destination displays and electric news from a distance.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an embodiment of a dot matrix display device according to the present invention.
FIG. 2 is an explanatory diagram showing an example of a hollow portion of the lens case shown in FIG.
FIG. 3 is a diagram illustrating an example of a conventional dot matrix display device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Display panel board | substrate 2 Light emitting element 4 Lens case 41 Convex part 42 Cavity part 43 Inclined surface 44 Cavity part

Claims (3)

A display panel substrate, a plurality of light emitting elements arranged in a matrix on the display panel substrate, and a lens case provided with a convex portion corresponding to each of the light emitting elements and provided on the surface side of the light emitting element The lens case has a hollow portion having a quadrangular bottom shape capable of enclosing the light emitting element inside the convex portion, and emits laterally from the light emitting portion to the outer periphery from the hollow portion. A gap having a flat inclined surface that reflects light toward the convex portion is formed in a lattice shape at the boundary between the plurality of light emitting elements, and the side wall of the cavity is surrounded by each light emitting element. Is provided in close contact with the display panel substrate so as to completely cover, and the inclined surface is formed to extend from the surface of the display panel substrate . less of the inclined surface While the larger the overlap with so that a part, a dot matrix display device are formed so as not connected by the convex portions and the convex portions for adjacent light-emitting element. The display device according to claim 1, wherein the side wall surface of the hollow portion is formed to be a curved surface or an inclined surface inclined toward the center side with respect to a vertical surface of the substrate. The display device according to claim 1, wherein a top surface of the hollow portion is formed to have a curvature larger than that of a flat surface or the convex portion of the lens case.

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