JP3173320B2 - Pilot lamp control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot lamp control device for illuminating operation buttons and the like of audio equipment mounted on a vehicle.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration of a conventional pilot lamp control device. In FIG. 3, reference numeral 1 denotes a power supply such as a vehicle-mounted battery, 2 denotes a constant voltage circuit connected to the power supply 1, and 3 denotes a lamp connected to the constant voltage circuit 2.
The voltage supplied from the power supply 1 is converted into a constant voltage by the constant voltage circuit 2, and the lamp 3 is turned on when a constant voltage is applied from the constant voltage circuit 2. FIG. 4 shows a lamp mounting structure in the conventional example. In FIG. 4, a lamp 3 is mounted on a printed circuit board 4, and a transparent panel 5
Is arranged. Lighting of the lamp 3 can be confirmed from the outside through the transmission panel 5.

[0003]

However, in the above-mentioned conventional pilot lamp control device, when the filament breaks due to the life of the lamp or the like, it is possible to immediately determine that the lamp has failed through the transmission panel. It was necessary to replace the lamp, and sometimes it was not clear how to remove the transmissive panel.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a pilot lamp control device capable of easily coping with a burned-out lamp.

[0005]

According to the present invention, in order to achieve the above object, the present invention is arranged behind a transmissive panel and close to each other.
A first lamp and a second lamp disposed therein;
A voltage detecting means which operates by a current flowing through the lamp and has a transistor for detecting the filament break of the first lamp; and
It is obtained by a switching transistor for turning on more operation and the second lamp voltage detected by the voltage detecting means.

[0006]

Therefore, according to the present invention, when the filament of the normally lit first lamp is broken, the second lamp is lit immediately, so that it is not necessary to replace the lamp each time, and the life of the lamp is reduced. Can be substantially doubled, and since it is not known from the outside that the lamp has burned out, the reliability can be improved.

[0007]

FIG. 1 shows the configuration of a pilot lamp control device according to an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a power source such as a vehicle-mounted battery, 12 denotes a constant voltage circuit connected to the power source 11, and 13 denotes a constant voltage circuit.
Is a first lamp for normal lighting, and 14 is a resistor connected between the first lamp 13 and the ground. Reference numeral 15 denotes a voltage detection circuit, which includes a resistor 1 connected to the constant voltage circuit 12.
6 and a transistor 1 having a collector connected to a resistor 16
7 and a resistor 18 connected to the base of the transistor 17.
And 19. The other end of the resistor 18 is the first lamp 1
The other end of the resistor 19 is grounded, and the emitter of the transistor 17 is also grounded. Reference numeral 20 denotes a second lamp for switching at the time of failure, which is connected to the constant voltage circuit 12. A switching transistor 21 has a collector connected to the second lamp 20, a base connected to the collector of the transistor 17,
The emitter is grounded.

FIG. 2 shows a lamp mounting structure according to this embodiment. In FIG. 2, the first and second lamps 1
Reference numerals 3 and 20 are attached near the printed circuit board 22, and a transmission panel 23 is disposed on the front surface thereof. From the outside, it can be confirmed through the transmission panel 23 that the lamp 13 or 20 is lit.

Next, the operation of this embodiment will be described.
In FIG. 1, when a power switch is turned on, a power supply 11 is turned on.
Is supplied to the first lamp 13 after being converted to a constant voltage by the constant voltage circuit 12, and the first lamp 13 is turned on. First
The lamp 13 has a constant current value when a certain voltage is applied depending on its type, so the voltage at the connection point a with the resistor 14 is also constant, and the voltage input to the voltage detection circuit 15 is also constant. . Therefore, the transistor 17 is turned on and the switching transistor 21 is turned off, so that the second lamp 20 does not light.

On the other hand, when the filament of the first lamp 13 is broken due to its life or the like, the open mode is set, and the input of the voltage detecting circuit 15 becomes zero volt. Therefore, the transistor 17 is turned off and the switching transistor 21 is turned off.
Is turned on, and the second lamp 20 is turned on instantaneously. Since the first lamp 13 and the second lamp 20 are disposed close to each other behind the same transmissive panel 23, even when the first lamp 13 is cut off and the second lamp 20 is turned on, when viewed from outside. Has less uneven lighting and uncomfortable feeling when switching.

As described above, according to the above-described embodiment, the filament break of the lamp is detected by utilizing the characteristic that the constant current flows during the normal operation of the pilot lamp and becomes open at the time of failure, so that a reliable detection operation can be obtained. The lamp can be switched instantly.

[0012]

According to the present invention, as is apparent from the above embodiment , the first lamp and the second lamp which are arranged close to each other behind the transmissive panel, and flow to the first lamp.
A voltage detecting means having a transistor for detecting broken filaments of operation to the first lamp by a current, wherein the
When the first lamp filament is broken, which includes a switching transistor for turning on the voltage detection hand operates more detected voltage <br/> stage the second lamp, the are normal lighting When the filament of one lamp is broken, the second lamp is immediately turned on, so that the trouble of replacing the lamp each time can be omitted, and the life of the lamp can be substantially doubled, and the first lamp is cut off.
And the second lamp is turned on, see the transmissive panel from outside.
In such a case, the feeling of strangeness at the time of switching is reduced, so that the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a pilot lamp control device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a mounting structure of the lamp in the embodiment.

FIG. 3 is a circuit diagram showing a configuration of a pilot lamp control device in a conventional example.

FIG. 4 is a sectional view showing a conventional lamp mounting structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Power supply 12 Constant voltage circuit 13 1st lamp 14, 16, 18, 19 Resistance 15 Voltage detection circuit 17 Transistor 20 2nd lamp 21 Switching transistor 22 Printed circuit board 23 Transmissive panel

Claims (1)

(57) [Claims] 1. A rear panel disposed close to a transmission panel.
A first lamp and a second lamp disposed therein;
A voltage detecting means which operates by a current flowing through the lamp and has a transistor for detecting the filament break of the first lamp; and
Pilot lamp control apparatus characterized by comprising a switching transistor for turning on more operation and the second lamp voltage detected by the voltage detecting means.