JPH0566718A - Light emitting diode display element - Google Patents

Abstract

PURPOSE:To surely turn OFF an LED lamp when an AC power source is turned ON and a three-pole bi-directional thyristor is turned OFF by connecting resistors in parallel at the input side of a diode bridge circuit rectifying an alternative current to a direct current. CONSTITUTION:A light emitting diode LED display element 31 is connected with a series circuit connected, for example, four LED lamps 33 in series via a current-limiting resistor 36 at the input side of the diode bridge circuit 35, while a shunt resistor 37 is connected at the input side of the diode bridge circuit 35 in parallel. When both an AC power source 41 and a triac 42 are turned ON, an AC current is made to flow through the diode bridge circuit 35 and is made to rectify and then each LED lamp 33 is turned ON with a current value properly controlled with the current-limiting resistor 36. On the other hand, when the AC power source 41 is turned ON and the triac 42 is turned OFF, a portion of a minute leakage current leaking from the triac 42 flows in the shunt resistor 37 and a minute current flowing in the diode bridge circuit 35 is decreased and each LED lamp 33 is turned OFF.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode display device suitable as a display device incorporated in a large number of road information boards.

[0002]

2. Description of the Related Art Conventionally, there is a road display panel of this type in which an incandescent lamp is incorporated as a display element. However, since the life of filaments in incandescent bulbs is not necessarily long with this, a large number of incandescent bulbs are regularly replaced, and the cost of incandescent bulbs at the time of replacement and the cost of replacement work are high. There is a problem of being bulky.

Therefore, only such an incandescent light bulb is a light emitting diode (hereinafter referred to as LED) having a long life and low power consumption.
It is conceivable to replace the LED display element with a built-in lamp with another one, such as an AC power source or a control panel.

As such an LED display element, for example, those shown in FIGS. 7A and 7B are conceivable.
The display element 1 has, for example, a plurality of LED lamps 3, 3 ... Built-in in the front opening of a cylindrical lamp case 2, and further is filled and fixed with an appropriate amount of a filling material 4 such as silicon. I am trying.

These LED lamps 3, 3 ... Are planted on one surface of a disk-shaped printed circuit board 5 in a matrix, for example, and a diode bridge rectifier circuit 6 and a current limiting resistor 7 are connected to the rear surface of the printed circuit board 5. A pair of contacts 9 and 10 of the base 8 are electrically connected to the rectifying circuit 6 and the current limiting resistor 7.

The electric circuit of the LED display element 1 is constructed as shown in FIG. 8. By mounting the base 8 in a socket of a display panel body (not shown), a pair of contacts 9 and 10 of the base 8 are connected to an AC power source. 11 and a triac 12, which is a three-pole bidirectional thyristor for controlling the on / off of the triac, are electrically connected, and each L is controlled by the on / off control of the triac 12.
The lighting of the ED lamp 3 is on / off controlled. The AC power supply 11 and the triac 12 are of the same standard as those for incandescent lamps.

Therefore, the LED display element 1 has a low impedance because the filament of the incandescent lamp is made of a conductor, whereas the rectifier circuit 6 made of a semiconductor and the LED are used.
Since it has the lamp 3, it has a feature of high impedance.

However, since the LED display element 1 is also connected to the AC power supply 11 of the same standard as that for lighting an incandescent light bulb of low impedance and the triac 12, the AC power supply 11 is turned on to turn on the triac 12. When turned off and in standby, the power supply voltage of the AC power supply 11 is divided by the triac 12 and the series circuit of the LED lamps 3 due to the high impedance of each LED lamp 3, and a minute current leaks from the triac 12.

Therefore, there is a problem that the leak current flows into the rectifier circuit 6 and the LED lamps 3 are turned on even when the triac 12 is turned off.

Further, in such an LED display element 1, a moisture-proof,
Since there is no standard for confirming the level for filling an appropriate amount of the filler 4 having a heat dissipation effect, there is a problem in that the filler 4 becomes excessive or insufficient.

Such a problem is shown in FIGS.
It also occurs in the LED display element 21 shown in (B).

The LED display element 21 has a plurality of LED lamps 23, 23 ... Built in a front opening of a prismatic lamp case 22, for example, and is filled with a filling material 24 to be fixed, and at the same time, moisture-proof and heat-radiating. I am trying to achieve the effect.

A lead wire 27 to which a connector 26 is connected is connected to a printed circuit board 25 on which the LED lamps 23 are arranged in a matrix.

However, this LED display element 21 is also shown in FIG.
As shown in (A) and (B), a step portion 28 for positioning and fixing the printed circuit board 25 is formed on the inner surface of the lamp case 22, and it is necessary to confirm whether or not an appropriate amount of the filling material 24 is filled. Since there is no standard for this, there is an excess or deficiency in the filling amount.

That is, as shown in FIGS. 11A and 11B, when the amount of the filling material 24 in the lamp case 22 is too small, both the moisture proof and the heat radiation effect are lowered, so that the weather resistance is lowered and the erosion is caused. Occurs, shortening the product life.

Further, as shown in FIGS. 12 (A) and 12 (B), when the filling material 24 is excessive, the area covering each LED lamp 23 increases and the light emitting area thereof decreases, so that the luminous intensity is reduced. This leads to a decrease in the viewing angle.

[0017]

As described above, in the LED display element 1 shown in FIG. 7, even when the AC power supply 11 is on and the triac 12 is off, the LED lamp 3 is turned on by the leak current from the triac 12. However, there is a problem that the display accuracy is reduced.

The LED display element 1 is shown in FIGS.
Similar to the LED display element 21 shown in, there is a problem that the filling materials 4 and 24 become excessive and deficient, the luminous intensity and the viewing angle are reduced, and the moisture-proof heat radiation effect is reduced.

Therefore, the present invention has been made in consideration of such circumstances, and an object thereof is to prevent the LED lamp from lighting even when the AC power supply is on and the triac is off, so that the LED lamp is surely turned off, and the display accuracy is improved. Another object of the present invention is to provide a light emitting diode display device capable of increasing the light emission.

Another object of the present invention is to provide a light emitting diode display element capable of easily and surely filling an appropriate amount with a filling material in a lamp case.

[0021]

The invention of the present application is configured as follows in order to solve the above problems.

The invention according to claim 1 of the present application (hereinafter, referred to as the first invention) includes a diode bridge circuit for rectifying alternating current from a three-pole bidirectional thyristor for controlling on / off of an alternating current power source to direct current, and this bridge circuit. In a light emitting diode display device having a light emitting diode lamp that is turned on by direct current, a resistor is connected in parallel to the input side of the diode bridge circuit.

The invention according to claim 2 of the present application (hereinafter referred to as the second invention) is a light-emitting diode display device in which a plurality of light-emitting diode lamps are built in a lamp case and filled with a filling material. The lamp case is characterized in that a step portion is formed to indicate a level at which the filling material should be filled in an appropriate amount.

Further, the invention according to claim 3 of the present application (hereinafter referred to as the third invention) is a light emitting diode display device having a plurality of light emitting diode lamps in a lamp case, wherein the plurality of light emitting diode lamps are provided. It is characterized by the provision of heat sinks for partitioning each.

The invention according to claim 4 of the present application (hereinafter referred to as the fourth invention) is characterized in that the heat dissipation plate is coated with a reflector on its side surface.

[0026]

[Action]

<First Invention> When the AC power supply is on and the three-pole bidirectional thyristor is off, the AC power supply voltage is divided by the thyristor and the high-impedance LED lamp, and a minute current leaks from the thyristor.

Since this leak current is shunted to the resistors connected in parallel to the input side of the diode bridge circuit, L
The current flowing into the ED lamp is significantly reduced and its lighting is prevented. Therefore, according to the present invention, the LED lamp can be surely turned off when the AC power supply is on and the three-pole bidirectional thyristor is off, so that the display accuracy of the display panel incorporating this LED display element can be improved.

<Second Invention> Since the lamp case has a step portion indicating a level at which an appropriate amount of the filling material should be filled, the filling material can be easily filled in the lamp case by filling the filling material up to this step portion. It is possible to reliably fill an appropriate amount and prevent the excess and deficiency.

Therefore, according to the present invention, it is possible to prevent the decrease of the luminous intensity and the viewing angle, the prevention of moisture, the decrease of the heat radiation effect and the shortening of the life of the LED lamp due to the excess and deficiency of the filler.

<Third Invention> Each LED display element generates heat when it is turned on, but since heat dissipation is promoted by the heat dissipation partition plate, the temperature rise of the LED lamp can be suppressed. Therefore, the life of the LED lamp can be prevented from being shortened due to the temperature rise, and the life of the LED lamp can be extended.

<Fourth Invention> Since the light emitted from each LED lamp is reflected and diffused by the reflector of the heat dissipation partition plate around each LED lamp, the viewing angle can be widened and the visibility can be enhanced.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the first to fourth inventions of the present application will be described below with reference to FIG.
~ It demonstrates based on FIG.

2 (A) and 2 (B) are a front view and a side sectional view of an embodiment of the first invention of the present application.
The display element 31, for example, has a plurality of LED lamps 33, 33 ... Built-in in the front opening of a cylindrical lamp case 32, and is further filled with a filler 34 having a moisture-proof and heat-dissipating effect so that each LED lamp 33 is enclosed in the lamp case. It is fixed inside 32 to prevent moisture and dissipate heat.

These LED lamps 33 are planted in a matrix on one surface of a disk-shaped printed board 34a, and a diode bridge rectifying circuit 35 composed of a plurality of diodes 35A is provided on the back surface of the printed board 34a.
The current limiting resistor 36 and the current dividing resistor 37 are connected to each other.

The rectifier circuit 35 has its pair of input ends electrically connected to a pair of contacts 39, 40 of a base 38 fitted and fixed to the rear portion of the lamp case 32.

The base 38 is attached to the socket of the display panel body (not shown) so that the AC power source 4 can be connected as shown in FIG.
1 and a triac 42, which is a three-pole bidirectional thyristor that controls the on / off of the AC power supply 41. Since the AC power supply 41 and the triac 42 have the same standard as those for lighting an incandescent light bulb, a display device incorporating an incandescent light bulb as a display element can be shared by the LED display element 31.

As shown in FIG. 1, the LED display element 31 has four LED lamps 33, 33 on the output side of the diode bridge circuit 35 via a current limiting resistor 36.
.. are connected in series, while a shunt resistor 37 is connected in parallel to the input side of the diode bridge circuit 35.

This is because when the AC power supply 41 is on and the triac 42 is off, part of the minute leak current leaking from the triac 42 is shunted to the shunt resistor 37, and the minute current flowing into the diode bridge circuit 35 is further increased. This is to reduce it.

Next, the operation of this embodiment will be described.

In FIG. 1, when both the AC power supply 41 and the triac 42 are turned on, an AC current is given to the diode bridge rectifier circuit 35, where it is rectified into a direct current, and then an appropriate current value is set by the current limiting resistor 36. And is given to each LED lamp 33 to light them.

Here, when only the triac 42 is turned off while the AC power supply 41 is on, the power supply voltage of the AC power supply 41 is high impedance with the triac 42.
The voltage is divided by the series circuit of the D lamp 33 and the triac 4
A minute current leaks from 2.

A part of the leak current is shunted to the shunt resistor 37, and a part of the leak current shunted to the rectifier circuit 35 is further significantly reduced, so that the LED lamps 33 are turned off.

That is, according to this embodiment, the AC power source 41
Is ON and each LE is surely off when the TRIAC 42 is off.
The D lamp 33 can be turned off. Therefore, the LED lamp 33 is controlled by the on / off control of the triac 42.
Since it is possible to reliably turn on / off the lighting of, the display accuracy of the display element incorporating the LED display element 31 can be improved.

FIGS. 3 (A) and 3 (B) are a front view and a side sectional view of an embodiment of the second invention of the present application.
The display element 51 has a plurality of LED lamps 53, 53 ...
Further, an appropriate amount of filler 54 having a moisture-proof and heat-radiating effect is filled and fixed in the lamp case 52, and moisture-proof and heat-radiation are also achieved.

A lead wire 57 having a connector 56 is connected to a printed circuit board 55 on which the LED lamps 53 are arranged in a matrix.

The LED display element 51 has a step 58 for positioning for fixing the printed circuit board 55 in the lamp case 52 on the inner surface of the lamp case 52, and an appropriate amount of filler 54 in the front opening of the lamp case 52. Is formed with a level display step portion 59 for indicating the level for filling.

Therefore, by filling the leveling step portion 59 with the filling material 54, it is possible to always simply and reliably fill an appropriate amount, and prevent the excess or deficiency.

Therefore, it is possible to prevent a decrease in luminous intensity and a visual angle, a decrease in moisture-proof and heat-radiating effects, and a decrease in life due to an excess or deficiency of the filler 54.

FIG. 5A is a front view of an embodiment of the third invention of the present application, and FIG. 5B is a sectional view taken along the line BB of this front view. In the figure, the LED display element 61 is shown. In the front opening of the LED display element 51 shown in FIG. 3, a heat-dissipation partition plate 62 having a grid-shaped partition plate for partitioning the plurality of LED lamps 53, 53 ... 5 is characterized in that a plurality of fitting grooves 63, 63 for fitting and fixing the protruding outer end portions of 62 are respectively formed. Other than that, the LED display element 51 has substantially the same structure, and therefore FIG. In FIGS. 3A and 3B, the same parts as those shown in FIGS. 3A and 3B are designated by the same reference numerals, and the description of the overlapping parts is omitted.

That is, as shown in FIG. 6 (A), the heat radiating partition plate 62 is formed by forming a rectangular thin vertical plate 62a and a horizontal plate 62b of, for example, an aluminum plate having good heat conduction, at each of opposite ends. Make a notch in the length and make a lattice matching groove 62a1,
62b1 are formed at a required pitch.

Then, the lattice-matching grooves 62a1 and 62b1 of the vertical and horizontal plates 62a and 62b are fitted into each other at right angles to assemble them in a lattice form as shown in FIG. 6B.

Therefore, according to this embodiment, each LE is
When the D lamp 53 generates heat when it is turned on, the heat generated is radiated by the filler 54 and the heat radiating partition plate 62, respectively, so that the heat radiating effect is improved. Therefore, the temperature of each LED lamp 53 rises to a high temperature, the forward current decreases, and the luminous intensity decreases.
It is possible to prevent the life of each LED lamp 53 from becoming short.

A reflecting film (not shown), which is a reflector, may be attached to each side surface of the heat radiating partition plate 62. According to this, the light emitted from each LED lamp 53 is emitted by the reflecting film. By reflecting and diffusing the light, the diffusion effect can be enhanced, the viewing angle can be expanded, and the visibility can be enhanced.

[0054]

As described above, the first invention of the present application is
When the AC power supply is on and the three-pole bidirectional thyristor is off, part of the minute leak current leaking from this thyristor can be shunted by the resistance on the input side of the diode bridge circuit.
The minute leak current flowing into the D lamp can be further reduced to prevent the LED lamp from lighting.
In other words, L is controlled by the on / off control of the 3-pole bidirectional thyristor.
Since the lighting of the ED lamp can be reliably controlled to be turned on and off, the display accuracy of a display device incorporating these LED lamps can be improved.

Further, according to the second aspect of the present invention, by filling the lamp case up to the step portion showing the level at which an appropriate amount of the filling material should be filled, the filling material can be filled easily and surely.

Therefore, it is possible to prevent a decrease in luminous intensity and a viewing angle, a decrease in moisture-proof and heat-radiating effects, and a decrease in life due to an excess or deficiency of the filling amount of the filler.

Further, according to the third invention of the present application, the heat generated when the LED lamp is turned on can be radiated by the heat radiating partition plate and the heat radiating effect can be enhanced, so that the LED lamp can be prevented from being heated to a high temperature. Therefore, it is possible to prevent the lamp from being heated to a high temperature and shorten the life thereof, and to extend the life thereof.

Further, in the fourth invention of the present application, since a reflector is applied to the heat dissipation partition plate of the third invention, light from each LED lamp is reflected by the heat dissipation partition plate reflector to diffuse light. The effect can be enhanced, the viewing angle can be expanded, and the visibility can be enhanced.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of the LED display element shown in FIG.

FIG. 2A is a front view of a light emitting diode display element according to the first invention of the present application, and FIG. 2B is a side sectional view of FIG.

FIG. 3A is a front view of an embodiment of the second invention of the present application,
(B) is a side sectional view of the (A).

4A is a front view of the lamp case shown in FIGS. 3A and 3B, and FIG. 4B is a side sectional view of FIG.

5A is a front view of an embodiment of a light emitting diode display device according to the third invention of the present application, and FIG. 5B is B of this FIG.
-B line sectional view.

6A is an exploded perspective view of the heat dissipation partition plate shown in FIG. 5,
FIG. 6B is a perspective view of the heat dissipation partition plate shown in FIG. 5 in an assembled state.

FIG. 7A is a front view of a conventional LED display element,
(B) is a side sectional view of the (A).

8 is an electric circuit diagram of the LED display element shown in FIG.

FIG. 9A is a front view of another conventional LED display element,
(B) is a side view of this (A), and (C) is a longitudinal sectional view of this (B).

10A is a front view of the lamp case shown in FIG. 9,
(B) is a side sectional view of this (A).

11A is a front view when the filling amount of the filling material of the LED display element shown in FIG. 10 is too small, and FIG.
FIG.

12A is a front view showing a state where the filling amount of the filling material of the LED display element shown in FIG. 9 is excessive, and FIG. 12B is a side sectional view of FIG.

[Explanation of symbols]

 31, 51, 61 LED display element 32, 52, 62 Lamp case 23, 33, 53 LED lamp 34 Filler 37 Dividing resistance 59 Level display step

Claims (4)

[Claims] 1. A light emitting diode display device comprising: a diode bridge circuit for rectifying alternating current from a three-pole bidirectional thyristor for controlling on / off of an alternating current power supply to direct current; and a light emitting diode lamp lit by direct current from the bridge circuit. A light emitting diode display device, wherein a resistor is connected in parallel to the input side of the diode bridge circuit. 2. In a light emitting diode display device in which a plurality of light emitting diode lamps are built in a lamp case and filled with a filling material, a step portion indicating a level at which the filling material should be filled in an appropriate amount is formed in the lamp case. A light emitting diode display device characterized by the above. 3. A light emitting diode display device having a plurality of light emitting diode lamps in a lamp case,
A light emitting diode display device comprising a heat dissipation plate for partitioning the plurality of light emitting diode lamps. 4. The light emitting diode display device according to claim 3, wherein the heat radiating plate has a reflector on its side surface.