JPS6255280B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fluorescent illumination device, more specifically, a fluorescent light that is illuminated under normal conditions (ordinary or normal state) when a failure occurs due to the end of its lifespan or the like. The present invention relates to a fluorescent lighting system in which an auxiliary fluorescent light immediately replaces the failed fluorescent light.

Fluorescent lamps are widely used today as excellent lighting equipment, but as is well known, when a fluorescent discharge tube reaches the end of its life, unlike a light bulb, the discharge sustaining voltage approaches or exceeds the power supply voltage, and the discharge stops. cannot continue and the light goes out. However, in the case of a preheating type starting device, the glow lamp immediately starts discharging and preheats the cathode heater of the fluorescent discharge tube to encourage discharge of the tube, but the discharge cannot be maintained and the light goes out again. Therefore, preheating with a glow lamp, tube discharge,
Turning off the light, discharging the glow lamp, and preheating must be repeated repeatedly, which is very unsightly and often irritates people's nerves.

Fluorescent lights are used for lighting in places where tubes cannot be easily replaced due to their long lifespan, but if some kind of failure occurs or the end of their lifespan is reached, the above phenomenon will not occur. Inevitable.

The present invention has been made in view of the above-mentioned conventional circumstances, and therefore, an object of the present invention is to switch to a backup fluorescent light at the same time as the main fluorescent light of the above-mentioned lighting equipment reaches the end of its life or other trouble occurs. The object of the present invention is to provide a novel fluorescent lighting device that can stably continue lighting at all times.

The above-mentioned object of the present invention is to
a second fluorescent light that turns on when the first fluorescent light fails; and a heater drop voltage of the first fluorescent light is monitored to detect a failure of the first fluorescent light. a fault detection means for detecting a fault detection means; a switching drive means for driving a switching means actuated by the output of the fault detection means to switch the power source from the first fluorescent light to the second fluorescent light; and the switching drive This is achieved by a fluorescent illumination device comprising a holding means for maintaining the driving state of the means.

According to the present invention, when the main fluorescent light reaches the end of its lifespan, it is automatically switched to the backup fluorescent light, and the main fluorescent light can be replaced with a new one until the end of the lifespan of the backup fluorescent light. By doing so, the illumination can be stably and continuously provided.

Here, before explaining the embodiments, the principle of the present invention will be briefly explained. In the case of an incandescent light bulb, the end of its life is due to a disconnection of the filament, and the electrical change is quite simple as the current required by the light bulb becomes zero from that point on, but in the case of a fluorescent light,
In the case of the preheating type starting method, even if the tube discharge stops and the light is turned off at the end of its service life, the glow lamp starts discharging within a moment, and after a while the tube cathode heater starts preheating by touching the glow lamp electrode, and the glow starts. The lamp discharge is stopped and the discharge shifts to tube discharge, but it cannot continue and the light goes out, and the discharge of the glow lamp is repeated again. However, during this time, the current flowing from the power supply does not become zero, and is not uniform because small, large, and sometimes strong impulse-like transient phenomena also occur on top of it. As described above, electrical changes due to the end of life appear in various places as changes in current in the power supply circuit, drops in fluorescent tube terminals, heater terminals, glow lamp terminals, ballast terminals, etc., and changes in induced voltage. In the present invention, we focus on the drop voltage of the fluorescent tube heater, which has the largest difference between the normal state, that is, normal lighting, and the fault occurrence, that is, abnormal lighting, and that provides an appropriate signal as a sensing part, and calculates the drop voltage. It is being used effectively. In other words, this voltage has a considerable drop due to the heater current during preheating with a glow lamp, and after startup has finished and the fluorescent tube has transitioned to normal discharge, there is only a small voltage drop due to a portion of the discharge current, so it is not a problem. Sometimes, the fluorescent tube cannot maintain its discharge and repeats abnormal blinking in turn with the glow lamp, and as a result, the heater preheating is repeated without interruption, so the drop voltage repeatedly changes from large to small. It is ideal as a detection signal in the event of a failure.

However, depending on the magnitude of the voltage drop, there is a problem in immediately switching to the standby fluorescent light.
Since the heater is preheated by the glow lamp even when the main fluorescent light is switched to the normal lighting for the first time, a delay circuit is required in this case to prevent erroneous switching. In the present invention, the above object is achieved by integrating and accumulating the wave height and waveform of the signal voltage due to the voltage drop of the fluorescent tube heater, and performing a switching operation when a certain amount is reached, without using any complicated method. are doing.
This is also one of the major features of the present invention.

Next, a preferred embodiment of the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing an embodiment of a fluorescent lighting device according to the present invention. In the figures, reference symbols
GL1 is a glow lamp, FL1 is a main fluorescent light, FL2 is a backup fluorescent light, and ST1 is a ballast. Fault detection circuit 1 that monitors the magnitude of the voltage drop due to the heater current of the fluorescent light and detects the occurrence of a fault in the fluorescent light.
1 is constituted by a time constant circuit consisting of a resistor R1, a diode D1, and a capacitor C2.
Reference number 12 indicates a switching circuit that switches the power to the backup fluorescent light FL2 when a failure occurs in the main fluorescent light FL1, and connects relay RY1 and contact ry1 of relay RY1.
It is made up of. A switching drive circuit 13 that is activated by the detection output of the fault detection circuit 11 to drive the switching circuit 12 is constituted by, for example, a transistor Q1 and a Zener diode ZD1. A holding circuit 14 that maintains the driving state of the switching drive circuit 13 includes a transistor Q2, a resistor R3, and the like. Each of the circuits 11, 12, 1
The configurations No. 3 and 14 are merely examples, and various other modifications are easily conceivable. A circuit 15 constituted by a diode D2, a resistor R6 and a capacitor C3 represents a rectifier circuit. The part surrounded by the dotted line in Fig. 1 is the main body of the device, and the other parts show the connections to the main fluorescent light FL1 and the backup fluorescent light FL2, and the relay contact ry1.
The contact position is assumed to be on the terminal M side as shown in the figure in the normal state (normal state).

The operation of this embodiment will be explained below. Now, when a commercial voltage of 100 VAC is applied to the power supply side, the main fluorescent light FL1 starts discharging via the relay contact ry1 and the terminal M through cathode preheating by the glow lamp GL1, and is turned on. On the other hand, the power supply voltage is also supplied to the electronic circuits in the device, and approximately 110 VDC is obtained between the rectifying circuit 15 and the two central elements constituting the switching drive means 13 and the drive state holding means 14. is applied to the collectors of transistors Q1 and Q2 through relay RY1 and resistor R4, respectively. However, transistor Q2
The base of the transistor Q1 is forward biased by the resistors R3 and R5, so it becomes conductive and turns on. However, the relay driving transistor Q1 has a Zener diode ZD1 connected between its emitter and ground. , the collector current does not flow until the base potential reaches a predetermined threshold level with respect to ground and becomes forward biased (in this example, a 3.3V Zener diode ZD1 is used, and a C780AGY is used as the transistor Q1. (For transistor Q1 to conduct, its base potential must be about +4V with respect to ground).

Further, in the embodiment, the rectifier circuit 15 is a single-phase half-wave rectifier circuit, but since the current half-wave rectified by the diode D2 is charged to the capacitor C3, the capacitor C3 is charged during the reverse half cycle. Current flows through relay RY1 and transistor Q
1 and Q2.

Therefore, the drop voltage of the negative heater due to cathode preheating when the fluorescent light FL1 is started is not a pure sine wave, but it is generated as a zero-to-peak alternating current of approximately 20V, and this voltage is output as a signal to terminal P, and is connected to the resistor. It is input to R1. The irregular AC voltage of about 20V input to this resistor R1 is connected to the capacitor C.
After the harmful noise is reduced by the diode D1, the wave is detected by the diode D1 and converted to direct current, and the capacitor C2
is applied to Therefore, the capacitor C2 accumulates charge due to this voltage, but since the cathode preheating time for a normal fluorescent lamp to start is completed within about 1 second, the fluorescent lamp FL1 is normally activated. The base potential of the transistor Q1, that is, the terminal voltage of the capacitor C2, does not reach a predetermined threshold level (approximately 4 V in this implementation) or higher because the time constant with the resistor R1 is set to several seconds. Since transistor Q1 cannot turn on and no collector current flows, relay RY1 does not operate.

In this way, even if a zero-to-peak voltage of about 20V is drawn into the terminal P, and this is detected and converted to DC, and the capacitor C2 begins to be charged, the capacitor terminal voltage will not reach the terminal P due to the time constant due to the resistor R1. If the signal voltage does not accumulate for a certain period of time, it will not reach the specified threshold level, i.e., approximately 4 V here, and therefore resistor R1 and capacitor C
In the present invention, the time constant circuit constituted by 2 and 2 functions as a delay circuit, and this is one of the major features of the present invention.

In addition, after the fluorescent light FL1 lights up normally, the signal voltage appearing at terminal P is about 2 to 3 V from zero to peak due to a slight drop due to the discharge current of the fluorescent light, but this level of voltage is continuous. Since the terminal voltage of the capacitor C2 cannot permanently exceed 4V even if the voltage is applied to the capacitor C2, the relay RY1 remains in the normal state without operating, and therefore the fluorescent light FL1 continues to be lit.

Next, if the fluorescent light FL1 cannot maintain normal lighting due to a failure such as reaching the end of its life and goes out,
As described above, due to the mechanism of this type of device, the glow lamp immediately starts discharging, and then the glow electrode is touched and the cathode is preheated. A characteristic of the cathode is that preheating of the cathode at the end of its life is repeated, and this device operates based on this major characteristic. That is, when a zero-to-peak signal of about 20V is repeatedly input to the terminal P, the signal voltage is detected by the diode D1 and charged to the capacitor C2, so that the terminal voltage becomes a continuous charge. As the voltage accumulates, the voltage exceeds 4V, which is the threshold level of this embodiment, in 10 to 30 seconds. Only when the base potential of the transistor Q1 rises to such a state does the base current begin to flow, so that the transistor Q1 becomes "on" and the collector current also begins to flow. This, combined with the presence of the relay winding resistance and the high impedance (3.3 kilohms) of the DC power circuit, results in a sudden drop in the potential at the point. The drop in potential at the point is transmitted to transistor Q2 through resistor R3, resulting in a drop in its base voltage, turning transistor Q2 into an "off" state and causing a rise in its collector potential, which causes the collector of transistor Q2 to pass through resistor Q2. It is connected to supplying the base current of transistor Q1 via R2. Relay RY1 is operated by the collector current of transistor Q1, and its contact ry1 is switched from terminal M to S.
The power supply voltage is supplied to FL2 instead of the fluorescent light FL1, and the fluorescent light FL2 comes to light up. In this way, with the two semiconductor element groups forming the positive feedback circuit, once the relay RY1 is activated by the signal from the terminal P, the relay will continue to operate even if the signal from the terminal P disappears. The relay will remain switched until the power is turned off.

By the way, as mentioned above, since the diode D2 of the rectifier circuit 15 is a half-wave rectifier, no current flows through the diode D2 during the reverse half cycle, but the current that flows during the forward direction charges the capacitor C3. Therefore, during this reverse half cycle, the current charged in capacitor C3 is supplied to relay RY1.

It is preferable that the relay used be a DC type with high voltage (however, 100V or less) and low current. As a result of actual measurements with this circuit, this circuit has a power supply voltage of 85V~
It was confirmed that it operates stably at 115V, ambient temperature -25℃ to +63℃, and any combination of these conditions. Furthermore, as shown in FIG. 1, there is no practical problem in connecting to a fluorescent light even if the ballast and glow lamp for the backup fluorescent light are omitted.

As explained above, the present invention is characterized by the difference between the drop voltage of the negative heater when the main fluorescent light is normally on and the heater drop voltage for preheating at startup, and because startup preheating is performed repeatedly in the event of a failure such as the end of service life. Applying the fact that preheating heater drop voltage can be accumulated, the accumulated drop voltage is detected to determine if the main fluorescent light is faulty or defective, and the standby fluorescent light is switched to and maintained in that state. It is something. Therefore, according to the present invention, it is possible to accurately detect and judge the main fluorescent light in which a fault has occurred, immediately control the switching of the main fluorescent light to the backup fluorescent light, and reliably maintain that state. All of the conventional drawbacks mentioned above are eliminated.

Although the present invention has been described above with respect to one preferred embodiment thereof, this is merely an example;
In addition to the embodiments described herein, the present invention includes various modifications. For example, although a bipolar transistor is used as the switching element in this embodiment, a field effect transistor or a semiconductor element such as a thyristor can be used instead by slightly changing the circuit constants. It is also possible to use semiconductor switching elements instead of relays.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a fluorescent lighting device according to the present invention. FL1...Main fluorescent light, FL2...Backup fluorescent light,
GL1... Glow lamp, ST1... Ballast, RY
1... Relay, ry1... Contact of relay ry1, 11
...Fault detection circuit, 12...Switching circuit, 13...
Switching drive circuit, 14... Drive state holding circuit, 15
... Rectifier circuit.

Claims (1)

[Scope of Claims] 1. A first fluorescent light that is turned on under normal conditions, a second fluorescent light that is turned on when a failure occurs in the first fluorescent light, and a heater drop voltage of the first fluorescent light. monitoring to detect occurrence of a failure in the first fluorescent light;
fault detection means constituted by a time constant circuit consisting of a resistor and a capacitor connected in series via a diode; and a fault detection means actuated by the output of the fault detection means to switch the first fluorescent light to the second fluorescent light. a switching drive means for driving a switching means for switching the power source;
It has a holding means for maintaining the driving state of the switching driving means, and a rectifying means for stably supplying direct current to the switching means, the switching driving means, and the holding means,
A fluorescent lighting device characterized in that, by each of these means, when a failure occurs in the first fluorescent light, the second fluorescent light is automatically switched on and turned on. 2. The fluorescent lighting device according to claim 1, wherein the switching means is a relay. 3. The fluorescent lighting device according to claim 1, wherein the switching drive means is constituted by a transistor that is turned on by the charge accumulated in the capacitor of the failure detection means. 4. The holding means is turned on when the transistor is off, and turned off when it is on, thereby supplying a charge to the base of the transistor so as to maintain the on state of the transistor, and a resistor. Claim 1 characterized in that it consists of
Fluorescent illumination device as described in section.