JP2729899B2 - LED lights for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular lamp, and more particularly, to a vehicular lamp such as a taillight, which uses a plurality of LED elements as a light source. .

[0002]

2. Description of the Related Art A conventional LED lamp 90 for a vehicle of this type is used.
FIG. 7 shows an example of a configuration of a lamp 90 (hereinafter referred to as a lamp 90) in a state of a wiring diagram. When the lamp 90 is used for a vehicle, it is desirable that the lamp 90 be turned on at least from 8V. This demand is no exception when the LED element 91 is used as a light source. Therefore, in a lamp 90 in which the LED element 91 whose lighting voltage is approximately 2 V is used as a light source, four of the LED elements 91 are used. The element 92 is connected in series, and the element 9
The required number of 2 is connected in parallel to form the lamp 90, thereby satisfying the above-mentioned rules.

At this time, a current limiting resistor 93 is connected in series with each of the elements 92, and an appropriate current (for example, 13 V) is supplied to each of the LED elements 91 at a power supply voltage (for example, 13 V) in a normal state of the vehicle. For example, the illuminance of the lamp 90 in the normal state is set, and the power supply voltage is set to 1 (for example, 150 Ω).
It is assumed that the LED element 91 does not break down due to an overcurrent when the voltage rises to 6V to the maximum.

[0004]

However, in the conventional configuration described above, the element 92 is set to the minimum lighting voltage of 8 V as described above,
The current limiting resistor 93 has a power supply voltage of 8V to 16V.
This corresponds to a wide range, and specifically, when the power supply voltage rises to 16 V, the power consumption is 0.4 W, which is almost the same as the power required to turn on the element 92. The limiting resistor 93 causes a considerable temperature rise.

At the same time, since the current limiting resistor 93 is connected for each element 92, it must be housed in the lamp body 94 of the lamp 90. In the lamp 90 provided with a large number 92 and the lighting time is also continued,
The internal temperature of the lamp body 94 rises, causing a decrease in the brightness of the LED element 91, making it impossible to satisfy the taillight standard,
Alternatively, the light emitting surface of the lamp 90 has a problem in that it has brightness unevenness in the same shape as the temperature distribution, which makes it difficult to see, and it has been a problem to solve these points.

[0006]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, a plurality of LEDs are provided.
A lamp is constituted by a plurality of elements in which elements are connected in series, and in a vehicle LED lamp in which a minimum lighting voltage is set for the lamp, the number of the elements is such that the lighting voltage exceeds the minimum lighting voltage. An LED device for a vehicle, comprising: an LED element connected in series, and a bypass resistor connected in parallel to the LED element exceeding the minimum lighting voltage of the element. This is to solve the problem.

[0007]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 shows a first embodiment of the present invention in the state of a wiring diagram, and the one indicated by reference numeral 1 in the figure is a vehicle LED lamp (hereinafter, referred to as lamp 1). The lamp 1 is the same as the conventional example in that the required number of LED elements 2 are connected in series and the required number of elements 3 are formed by connecting a required number of parallel connections.
According to the present invention, the number of LED elements 2 exceeding the minimum lighting voltage of 8 V set for lighting is connected to the element 3 in series. Has a configuration in which bypass resistors 4 are connected in parallel.

In the following, the above configuration will be described in detail with a concrete example. First, the element 3 is configured by connecting, for example, five LED elements 2 in series. Is about 2 V × 5 times and about 10 V, and a current (for example, 30 mA) capable of generating a prescribed illuminance at a prescribed power supply voltage (for example, 13 V) can flow through these elements 3. A current limiting resistor 8 having a resistance value is connected in series.

At the same time, the number of LED elements 2 exceeding the minimum lighting voltage of 8 V of the element 3 (for example, if the element 3 is composed of five LED elements 2, one of them) For example, a bypass resistor 4 of 400 to 600Ω is connected in parallel. At this time, the LED element 2 to which the bypass resistor 4 is connected is connected.
May be at any position of the element 3.

Next, the lamp 1 of the present invention having the above-described structure.
The operation and effect of will be described. Note that, for the sake of specific description, the description will be made assuming that the element 3 is composed of five LED elements 2 in series. First, since the element 3 is composed of five LED elements 2 in series, the basic lighting voltage is approximately 10 V, and even when the vehicle power supply voltage is the design reference value of 13 V, the current limiting resistor 8 is used.
It is sufficient to bear (power supply voltage 13 V)-(lighting voltage 10 V) = 3 V. Therefore, the conventional LED element 2 is composed of four series (power supply voltage 13 V)-(minimum lighting voltage 8).
V) = 5 V, the power consumption of the current limiting resistor 8 is reduced to approximately 60%, and the heat generation in the lamp body 6 is naturally reduced.

Next, description will be made in a state where the power supply voltage on the vehicle side is 10 V or less. In this state, it is naturally impossible to turn on all the five LED elements 2 having the elements 3. The LED element 2 to which the bypass resistor 4 is connected is turned off. Since the unlit LED element 2 at this time has a substantially infinite resistance value, the current flows around the bypass resistor 4 to keep the other four LED elements 2 lit. Becomes
As a result, the unlit state of the entire lamp 1 is avoided.

That is, in the configuration of the present invention, in the power supply voltage range of 8 to 10 V where only the lighting is desired, four out of the five elements 3 are turned on, so that the entire lamp 1 is turned on. Will fulfill the function of avoiding non-lighting, and will fulfill the specified function having the specified illuminance in the range of 10 V or more. .

FIG. 2 shows a second embodiment of the present invention. In the first embodiment described above, the element 3 is formed as a series of five LED elements 2. In the example, the element 13 is formed as a series of six LED elements 2, and the bypass resistor 4 is connected in parallel to the minimum lighting voltage of 8 V, that is, to each of the two LED elements 2.

In this case, four LED elements 2 in the element 13 are turned on in the power supply voltage range of 8 to 10 V, and five LED elements are turned on in the range of 10 to 12 V.
Therefore, in the second embodiment, the current limiting resistor 18 only needs to bear 1 V at the time of lighting at the specified power supply voltage of 13 V, and the power consumption is remarkably 20%. Although the illumination intensity is reduced, the specified illuminance of the lamp 1 is guaranteed to be 12 V or more. Therefore, the second embodiment is determined to be used in consideration of the destination-related standards applied to the lamp 1 and the like. Will be.

FIG. 3 shows a third embodiment of the present invention. In each of the previous embodiments, the current limiting resistors 8 and 18 are provided in the elements 3 and 13, respectively.
In the third embodiment, the use of the constant current power supply 5 eliminates the need for the current limiting resistors 8 and 18 from the element 23.
This further reduces the amount of heat generated in the lamp body 6.

At this time, the constant current power supply 5 is capable of supplying a prescribed current (for example, 30 mA) to each element 23 (for example, if the elements 23 are arranged in 20 rows, the required current is 30 mA). × 20 = 600 mA), that is, the constant current power supply 5 having a capacity corresponding to the number of the elements 23. At this time, the constant current power supply 5 may perform a constant current operation in a power supply voltage range of 10 V to 16 V where it is required to maintain a specified illuminance for the lamp 1.

With the above construction, in the lamp 1 of the third embodiment, five LED elements 2 are turned on in the range of the power supply voltage of 10 V to 16 V, and the power supply voltage of 8 V to 10 V.
In the range of V, the same operation as in the first embodiment in which four lamps are turned on can be achieved, but with the provision of the constant current power supply 5, the current limiting resistor 8 becomes unnecessary,
The temperature rise in the lamp body 6 can be further reduced. Since the constant current power supply 5 can be installed outside the lamp body 6 as shown in the figure, the provision of the constant current power supply 5 does not become a new heat source in the lamp body 6. Further, the third embodiment can be implemented in combination with the second embodiment.

FIG. 4 shows a fourth embodiment of the present invention. Unlike the previous embodiments in which each of the elements 3 and 13 is provided with the bypass resistor 4, In the fourth embodiment, as shown in FIG.
The bypass resistor 14 is provided in such a manner that the number of parts can be reduced, and the bypass resistor 14 can be easily moved to the outside of the lamp body 6. It is even more effective in reducing the amount of heat generated in the interior.

FIG. 5 shows a fifth embodiment of the present invention. As shown, a plurality of LED elements 2 connected in parallel are further connected in series to form an element 43. A bypass resistor 24 is provided for a plurality of the elements 2 connected in parallel. In this case, it is required that there is no variation in the lighting voltage between the LED elements 2 connected in parallel. , The number of bypass resistors 24 can be reduced, and, for example, even when one LED element 2 is disconnected, the current can bypass the other LED elements 2 connected in parallel, This prevents the whole of the elements 43 in a row from being turned off.

FIG. 6 shows a sixth embodiment of the present invention. In each of the third to fourth embodiments, the constant current power supply 5 is used as the power supply. 6 also shows an example in which the constant voltage power supply 7 is combined with the circuit of the third embodiment (see FIG. 3).

At this time, the constant voltage power supply 7 is set to a voltage corresponding to the number of the five series LED elements 2 constituting the element 23, that is, approximately 10 V. The range of 10 V to 16 V is a constant voltage operation. Thus, the illuminance of the lamp 1 is made constant to satisfy the standard, and the current limiting resistor is omitted from the element 23. When the power supply voltage becomes 10 V or less, the lighting of the four LED elements 2 in the element 23 is continued by the action of the bypass resistor 4,
The requirement that only the lighting is specified shall be satisfied.

Therefore, the operation and effect when converted to the constant voltage power supply 7 are not changed at all, and the same applies to the circuits of the second, fourth and fifth embodiments. It is possible, and the same operation and effect can be obtained.

[0023]

As described above, according to the present invention, the element is formed by connecting a number of LED elements having a lighting voltage exceeding the minimum lighting voltage in series, and the number of the LED elements exceeding the minimum lighting voltage of the element is increased. A vehicle LED in which a bypass resistor is connected in parallel to the LED element
By using the lamp, the power consumption of the current limiting resistor in the lamp body is reduced to reduce the amount of heat generated.
The brightness reduction or uneven brightness that occurs in a lamp using an ED element as a light source is eliminated, and an extremely excellent effect on quality improvement is achieved.

Further, in addition to the above configuration, the vehicle LED lamp is connected to a constant current power supply corresponding to the number of the elements or a constant voltage power supply corresponding to the serial number of the LED elements forming the element. This eliminates the need for the current limiting resistor in the lamp body, further reduces the temperature in the lamp body, and further enhances its effect.

[Brief description of the drawings]

FIG. 1 is a wiring diagram showing a first embodiment of a vehicle LED lamp according to the present invention.

FIG. 2 is a wiring diagram showing a second embodiment of the present invention in a main part.

FIG. 3 is a wiring diagram showing a third embodiment of the present invention.

FIG. 4 is a wiring diagram showing a main part of a fourth embodiment of the present invention.

FIG. 5 is a wiring diagram showing a main part of a fifth embodiment of the present invention.

FIG. 6 is a wiring diagram showing a sixth embodiment of the present invention.

FIG. 7 is a wiring diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... LED lamp for vehicles 2 ... LED element 3, 13, 23, 33, 43 ... Element 4, 14 ... Bypass resistor 5 ... Constant current power supply 6 ... Lamp body 7 ... Constant voltage power supply 8 , 18 ... Current limiting resistor

Claims (3)

(57) [Claims] 1. A vehicular LED lamp in which a plurality of elements formed by connecting a plurality of LED elements in series constitute a lamp, and the lamp has a minimum lighting voltage set.
The element is formed by connecting a number of LED elements having a lighting voltage exceeding the minimum lighting voltage in series, and the LED elements exceeding the minimum lighting voltage of the element are formed.
An LED lighting device for a vehicle, wherein a bypass resistor is connected to the element in parallel. 2. The vehicle LED lamp according to claim 1, wherein a constant current power source corresponding to the number of said elements is connected to said vehicle LED lamp. 3. A vehicle LED, wherein a constant voltage power source is connected to the vehicle LED lamp corresponding to the number of the LED elements forming the element in series.
Lights.