JP2023155014A - LED device - Google Patents

Abstract

To provide an LED device capable of easily being downsized and allowing a plurality of LED elements connected in series to emit light even when one LED element of the plurality of LED elements goes down.SOLUTION: An LED device (1) comprises a light-emitting unit (50) composed of a first series light-emitting circuit (C1) connecting in series a first LED element (8), a second LED element, and a third LED element and a second series light-emitting circuit (C2) arranged in parallel to the first series light-emitting circuit and connecting in series a fourth LED element (8), a fifth LED element, and a sixth LED element. The LED device also comprises a first wiring (L1) connected between the first LED element and the second LED element and between the fourth LED element and the fifth LED element, a second wiring (L2) connected between the second LED element and the third LED element and between the fifth LED element and the sixth LED element, and a first Zener diode (7) arranged between the first wiring and the second wiring.SELECTED DRAWING: Figure 3

Description

The present invention relates to an LED device including a plurality of LED (Light Emitting Diode) elements connected in series and in parallel, and a Zener diode electrically connected to the plurality of LED elements.

LED devices are becoming widely used in backlights of display devices, lighting equipment, and the like. At ball game fields, ski resorts, golf courses, and the like, a plurality of LEDs are often arranged in a matrix to illuminate a wide area. For example, Patent Document 1 and Patent Document 2 disclose a matrix-like LED device in which a plurality of LED elements arranged in series are arranged in parallel.

In general, LED elements are prone to failure due to noise such as surge voltage and electrostatic discharge. That is, the LED element has a property of having a low reverse breakdown voltage. As a countermeasure against this problem, a technique has been disclosed in which a Zener diode is arranged in parallel with the LED element.

JP 2017-5185 Publication Japanese Patent Application Publication No. 2015-19090

However, if one of the plurality of LED elements fails, the plurality of LED elements arranged in series may stop emitting light, and the LED device may become useless. Moreover, in order for the plurality of series-connected LED elements to emit light even if one of the plurality of LED elements fails, Zener diodes must be connected in parallel to all the LED elements. This poses problems such as an increase in the size of the LED element substrate on which the Zener diode is arranged and an additional process for mounting the Zener diode.

Therefore, in order to solve the above-mentioned problems, the present invention provides an LED device that prevents the substrate size of the LED element from increasing and that even if one LED element of a plurality of LED elements fails, other LED elements continue to emit light. do.

The LED device of this embodiment includes a first series light emitting circuit in which a first LED element, a second LED element, and a third LED element are connected in series, and a first series light emitting circuit arranged in parallel with the first series light emitting circuit, and a fourth LED element and a fifth LED element. It has a light emitting section constituted by a second series light emitting circuit in which a sixth LED element is connected in series. Further, the LED device includes a first wiring connected between the first LED element and the second LED element, a fourth LED element and the fifth LED element, and a first wiring connected between the second LED element and the third LED element and the fifth LED element. and a second wiring connected between the first wiring and the sixth LED element, and a first Zener diode arranged between the first wiring and the second wiring.

The LED device of this embodiment further includes a positive power supply line to which the anode electrode of the first LED element and the anode electrode of the fourth LED element are connected, and a cathode electrode of the third LED element and the cathode electrode of the sixth LED element. It is preferable to include a negative power line and a surge protection element disposed between the positive power line and the negative electrode line.
Further, it is preferable that a reverse current prevention diode is disposed on the negative electrode line between the surge protection element and the first series light emitting circuit.
Furthermore, it is preferable to include a second Zener diode placed between the positive power line and the first wiring, and a third Zener diode placed between the negative power line and the second wiring.

In the LED device of this embodiment, the first LED element, the second LED element, the third LED element, the fourth LED element, the fifth LED element, the sixth LED element, and the first Zener diode are mounted on a circuit board, and the circuit board is coated with fluorine. It is preferable that the
The circuit board includes a positive power line to which the anode electrode of the first LED element and the anode electrode of the fourth LED element are connected, and a negative power line to which the cathode electrode of the third LED element and the cathode electrode of the sixth LED element are connected. , a surge protection element placed between the positive power supply line and the negative electrode line, and a reverse current prevention diode placed on the negative electrode line between the surge protection element and the first series light emitting circuit. You may prepare. Preferably, the circuit board is disposed below the plurality of optical units.
In the LED device of this embodiment, it is preferable that the first LED element, the second LED element, the third LED element, the fourth LED element, the fifth LED element, and the sixth LED element emit light using a constant current output from the same constant current circuit. .

The LED device of the present invention can be easily miniaturized, and even if one of the plurality of LED elements fails, the plurality of LED elements connected in series can emit light.

FIG. 3 is a perspective view of the front side of the LED device. FIG. 3 is a partial cross-sectional view of the LED device. FIG. 2 is a diagram showing a light emitting circuit having LED elements arranged in a matrix.

An LED device according to an embodiment of the present invention will be described. In the following embodiments, the present device will be described as a high-output type device used in a large sports facility such as an athletic stadium, a ball game field, a soccer field, or a golf course. Note that the drawings used in the explanation are shown schematically to the extent that these inventions can be understood, and the size, angle, thickness, etc. are exaggerated. Furthermore, in each figure used for the explanation, similar components are indicated by the same numbers, and the explanation thereof may be omitted. Furthermore, the shapes, dimensions, materials, etc. described in the following embodiments are merely preferred examples within the scope of the present invention.

<Outline of LED device>
As shown in FIG. 1, the LED device 1 includes a heat dissipation plate 12 incorporating a substrate on which a plurality of LED elements are arranged, and a plurality of optical units 2 (2-11 to 2-67) arranged on the output side of the substrate. , a protective guard 13 that is arranged on the output side of these optical units 2 and protects the heat sink 12. The protective guard 13 emits the light emitted by the LED element, and this output surface becomes the light emitting surface of the device 1.

Optical units 2-11 to 2-16 are arranged in the LED device 1 from the upper left to the upper right in FIG. Optical units 2-21 to 2-26 are arranged in the LED device 1 one step below (-Y axis side). At the bottom, optical units 2-71 to 2-76 are arranged in the LED device 1. For example, four LED elements 8 (see FIG. 2) are arranged in one optical unit 2. That is, the LED device 1 includes 168 LED elements 8. These optical units 2 may all have the same specifications or may have different specifications.

Note that the LED device 1 has a square shape when viewed from the front side (+Z-axis side), but may have a rectangular shape or a circular shape. The optical unit 2 is appropriately arranged according to the shape of the heat sink 12 of the LED device 1. Although the optical units 2 are arranged in a 7×6 matrix in FIG. 1, the optical units 2 are not limited to this, and may be arranged in a 10×10, 3×20, etc. matrix. The following description will be made on the premise that the LED device 1 includes 168 LED elements 8.

FIG. 2 is a partial cross-sectional view of the LED device 1, and is a cross-sectional view of the optical units 2-41 and 2-51. The LED device 1 includes an LED element 8, a circuit board 6 on which the LED element 8 is mounted, a heat sink 12, a protective guard 13, and the like. The optical axis L of the light from the LED element 8 is parallel to the Z-axis direction.

The heat sink 12 is made of metal such as die-cast aluminum, has a square or circular deep dish shape, and has an inner surface 12c on the front side (+Z-axis side). The heat sink 12 has a plurality of heat sinks 12h on the back side (-Z axis side). The heat sink 12h radiates heat generated by the light emission of the LED element 8 or the heat of the diode to the outside via the circuit board 6.

Further, the circuit board 6 is provided on the heat sink 12 so as to be in close contact with the inner surface 12c thereof. A plurality of LED elements 8 are soldered to the circuit board 6, and power is supplied to the LED elements 8 via the circuit board 6, so that the plurality of LED elements 8 are turned on. Although not shown, a diode or Zener diode, which will be described later, is also attached to the circuit board 6. The front side (+Z-axis side) 6c of the circuit board 6 on which the plurality of LED elements 8 and Zener diodes are arranged is coated with fluorine resin. This protects the circuit board 6 from moisture caused by wind and rain, and prevents corrosion damage to electronic components such as the LED elements 8 and Zener diodes.

Further, on the upper side (+Z-axis side) of the circuit board 6, a plurality of optical units 2, which will be described later, are arranged. In FIG. 2, optical units 2-41 and 2-51 having the same specifications are arranged so as to be fitted into the inner surface 12c. A protective guard 13 is arranged above the plurality of optical units 2 (on the +Z-axis side). The protective guard 13 is made of transparent glass or transparent plastic (polycarbonate, acrylic (PMMA), etc.) in order to emit the light emitted from the LED element 8, and protects and waterproofs the inside of the LED device 1. .

<Outline of light emitting circuit>
Next, the light emitting circuit will be explained using FIG. The light emitting circuit includes a rectifying section 30, a constant current section 40, and an LED light emitting section 50. The light emitting circuit causes the 168 LED elements 8 shown in FIG. 1 to emit light.

The rectifier 30 includes a bridge diode BD and a resistor R. The rectifier 30 rectifies the 100V AC voltage supplied to the power line PL into a DC voltage. The constant current section 40 has a configuration in which a constant current diode CD and a Zener diode CZ are connected in parallel. The surge voltage transiently applied to the constant current diode CD is controlled by the series circuit of the Zener diode CZ and the constant current diode CD to limit the current flowing to the LED light emitting section 50 to a predetermined constant current or less. A constant current value of the constant current diode CD is selected according to the brightness required in the LED light emitting section 50, and a maximum voltage is selected according to the selected constant current value.

Since the constant current diode CD is a semiconductor element to which voltage is applied in the forward direction, it is susceptible to surge voltages like the LED element 8, and if a surge voltage exceeding the maximum voltage is applied, normal semiconductor function will occur. may be damaged. Furthermore, each of the three constant current diodes CD has a Zener diode CZ connected in parallel to bypass the surge voltage transiently applied to the constant current diode CD to the Zener diode CZ. Each Zener diode CZ bypasses the surge voltage to prevent the voltage rectified by the bridge diode BD from concentrating on one of the three constant current diodes CD. Depending on the allowable power consumption, withstand voltage, etc., it is possible to use only one constant current diode CD and one Zener diode CZ.

In the LED light emitting unit 50, 168 LED elements 8 provided corresponding to the plurality of optical units 2 shown in FIG. 1 are arranged in a 14×12 matrix. Fourteen LED elements 8 are connected in series to each of the wirings C1 to C12. In this embodiment, a circuit in which the LED elements 8 are connected to one wiring C may be referred to as a series light emitting circuit. The anode electrode of each LED element 8 is connected to the wiring V+ side, and the cathode electrode of each LED element 8 is connected to the wiring V- side. The four LED elements 8 connected to the V+ side of the wiring C1 and C2 are LED elements corresponding to the optical unit 2-11, and the four LED elements 8 connected to the V- side correspond to the optical unit 2-11. This is an LED element corresponding to -71. Furthermore, the four LED elements 8 connected to the V+ side of the wiring C11 and C12 are LED elements corresponding to the optical unit 2-16, and the four LED elements 8 connected to the V- side are the LED elements corresponding to the optical unit 2-16. This is an LED element corresponding to 2-76.

Wirings L1 to L13 are connected to fourteen LED elements 8 connected in series from wiring C1 to wiring C12, respectively. A Zener diode 7 is connected to the wiring C13 in parallel with the wiring C1 to the wiring C12. Utilizing the characteristic that the forward voltage increases as the forward current of the LED element 8 increases, the Zener diode 7 is connected to each of the 12 LED elements 8 connected to each wiring C1, C2, . . . C12. connected in parallel. For example, the Zener diode 7 is connected in parallel to the LED element 8 connected to the wiring C1, the wiring L1, and the wiring L2. The same applies to the LED element 8 connected to the wiring C2, the wiring L1, and the wiring L2.

Note that the cathode side of the Zener diode 7 is connected to the anode side of the LED element 8, and the anode side of the Zener diode 7 is connected to the cathode side of the LED element 8. Further, the Zener voltage of the Zener diode 7 is preferably the same value as the forward voltage of the LED element 8 at the designed maximum allowable current, or a value smaller by a predetermined amount.

Even if one LED element 8 on the wiring C2 among the 168 LED elements 8 arranged in a matrix has a disconnection failure, a normal LED element 8 subsequent to the failed LED element 8 will be Since current is supplied through the connection path from the wiring C1 or the wiring C3, the normal LED element 8 in the subsequent stage emits light. Therefore, only the failed LED element 8 does not emit light, and the other LED elements 8 emit light, so that the reduction in brightness of the LED device 1 is small.

In addition, since the Zener diodes 2 are connected in parallel in each row, for example, when one LED element 8 has a disconnection failure and the current flowing to other normal LED elements 8 exceeds the maximum allowable current of the LED element 8, , a current exceeding the maximum allowable current begins to flow through the Zener diode 2, and as a result, the current value flowing through the remaining normal LED elements 8 can be maintained within the maximum allowable current value, and the normal LED element 8 is protected.

Further, the LED light emitting unit 50 has a Zener diode TVS as a surge protection element, and the cathode electrode of the Zener diode TVS is connected to the wiring V+ (positive power line) and the anode electrode is connected to the wiring V- (negative power line). There is. The Zener diode TVS is used as a countermeasure against electrostatic discharge (ESD).Assuming that a surge current may occur even if the constant current section 40 is present, the Zener diode TVS is used as a countermeasure against ESD. The 168 LED elements 8 are protected by being connected to the Zener diode TVS to bypass the surge current that is transiently applied to the LED elements 8 to the Zener diode TVS.

Further, the LED light emitting section 50 includes diodes BP1 and BP2 for preventing reverse current. The diodes BP1 and BP2 are connected to the wiring V- between the Zener diode TVS and the wiring C1. The diodes BP1 and BP2 prevent reverse current, which occurs when high frequency noise is input to the power supply line PL, from being input to the LED elements 8 arranged in a matrix. In this embodiment, two diodes BP1 and BP2 are arranged in parallel, but three or more diodes may be arranged in parallel, or only diode BP1 may be arranged.

1... LED device 2 (2-11 to 2-76)... Optical unit 6... Circuit board 7... Zener diode, 8... LED element 12... Heat sink, 13... Protective guard 30... Rectifier section, 40... Constant current section, 50...LED light emitting part C1-C13...Wiring, L1-L13...Wiring V+...Positive power line, V-...Minus power line TVS...Surge protection element (Zener diode)
BP1, BP2...Diode

Claims (7)

A first series light emitting circuit in which a first LED element, a second LED element, and a third LED element are connected in series, and a fourth LED element, a fifth LED element, and a sixth LED element are connected in series. a light emitting section composed of a second series light emitting circuit;
a first wiring connected between the first LED element and the second LED element and between the fourth LED element and the fifth LED element;
a second wiring connected between the second LED element and the third LED element and between the fifth LED element and the sixth LED element;
a first Zener diode disposed between the first wiring and the second wiring;
An LED device comprising: a positive power supply line to which an anode electrode of the first LED element and an anode electrode of the fourth LED element are connected;
a negative power supply line to which the cathode electrode of the third LED element and the cathode electrode of the sixth LED element are connected;
a surge protection element disposed between the positive power supply line and the negative electrode line;
The LED device according to claim 1, comprising: The LED device according to claim 2, further comprising a reverse current prevention diode arranged on the negative electrode line between the surge protection element and the first series light emitting circuit. a second Zener diode disposed between the positive power supply line and the first wiring;
a third Zener diode disposed between the negative power supply line and the second wiring;
The LED device according to claim 2, comprising: The first LED element, the second LED element, the third LED element, the fourth LED element, the fifth LED element, the sixth LED element, and the first Zener diode are mounted on a circuit board, and the circuit board is coated with fluorine. The LED device according to claim 1. The circuit board includes:
a positive power supply line to which an anode electrode of the first LED element and an anode electrode of the fourth LED element are connected;
a negative power supply line to which the cathode electrode of the third LED element and the cathode electrode of the sixth LED element are connected;
a surge protection element disposed between the positive power supply line and the negative electrode line;
a reverse current prevention diode disposed on the negative electrode line between the surge protection element and the first series light emitting circuit;
The LED device according to claim 5, wherein the circuit board is arranged below a plurality of optical units. From claim 1, wherein the first LED element, the second LED element, the third LED element, the fourth LED element, the fifth LED element, and the sixth LED element emit light by a constant current output from the same constant current circuit. The LED device according to claim 6.

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