JP2000331786A - Discharge lamp lighting circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of an electrode and extend the service life of a discharge lamp by comprising a main discharge circuit for supplying a heating current to each of a pair of electrodes of a discharge lamp, to apply a high voltage between the electrodes and a glow starter connected in parallel to the discharge lamp. SOLUTION: When a power switch 20 is turned on, a current is carried to a primary winding L11 or L12 of a leakage transformer Tr, and the electrodes 11, 12 of a fluorescent lamp are heated by the output current of filament windings F1, F2 to emit thermoelectrons. An output voltage is also generated in a main discharge circuit formed of the secondary winding L2 of the leakage transformer Tr, capacitors C1-C3 and a discharge resistor R to apply a high voltage between the electrodes 11 and 12 of the fluorescent lamp. At a stage where the thermoelectron quantity is insufficient, the current of the main discharge circuit is carried within a glow starter 21, so that no high voltage current is carried between the electrodes 11 and 12 of the fluorescent lamp, and the extension in service life of the fluorescent lamp can be thus attained without causing the deterioration of the electrode surface by sputtering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting circuit.

[0002]

2. Description of the Related Art Conventionally, as a lighting method of a fluorescent lamp, a glow lighting method (accidental lighting method by a bimetal in a glow starter) and a rapid start method are known. In the glow lighting method, a glow starter is connected in series with a pair of filaments (also serving as electrodes) of a fluorescent lamp, and the pair of filaments is heated by a current flowing during a connection period of a bimetal in the glow starter after heating by glow discharge. The main discharge of the fluorescent lamp is started by an induction kick when the bimetal cools and the current is cut off.
On the other hand, in the rapid start method, for the purpose of instantaneous lighting, a current is always applied to a pair of filaments, a high voltage is applied between the electrodes, and the filament is heated to emit thermoelectrons and discharge under the minimum condition. The main discharge starts spontaneously when the state is reached.

[0003] Filaments (electrodes) at both ends of the tube
The surface of the tungsten double coil filament,
Covered with oxides such as barium and strontium
It is designed to increase the radiation of the child, but as described above
Conventional instantaneous lighting method (including inverter type)
Means that the electrode deteriorates quickly and the life of the fluorescent lamp is shortened
There was a problem. Regarding this point, the electrode temperature and time at startup
This will be described with reference to FIG. Time t₁ At
Temperature T₁ In the case, thermal electrons that can be discharged are emitted
Time t _Three Temperature T at_Three Is sufficient heat to discharge
This indicates that electrons are emitted. In this case smell
Time 0-t₁ Electrode is gradually heated during the period of
It is a process, but before the emission of thermoelectrons begins,
Due to the high voltage applied, gas ions strike the electrode.
And the acid such as barium or strontium on the electrode surface.
The oxide coating is sputtered, leading to electrode degradation. That
Therefore, the temperature at which a dischargeable amount of thermoelectrons is released is T₁ Then
Not enough T_Two Vicious cycle of rising and taking more time
Is repeated to shorten the life of the electrode.

FIG. 7 is a graph showing the relationship between the temperature reached by the electrode and the amount of generated thermoelectrons when the electrode is normal (solid line) and when the electrode is deteriorated (dashed line). Here, the case where the electrode is normal refers to a state where the coating of the barium oxide or the like on the electrode surface is sufficient, and the case where the electrode has deteriorated refers to a state where the coating is lost by sputtering. In this graph, e ₁ is the amount of thermionic electrons required for discharge, e ₂ is the amount of thermionic electrons when the electrode is normal, e ₃ is the amount of thermionic electrons when the electrode is deteriorated, and T ₁ is the amount of thermionic electrons when the electrode is deteriorated. electrodes reach the temperature, T ₂ necessary for the discharge start time normal, the electrode reaches a temperature, T ₃ required discharge start when the electrode is deteriorated, an electrode temperature reached during stable discharge. From this graph, when the electrode starts to deteriorate,
The deterioration further increases in the temperature range of T _{1 to} T ₂ , and when the electrode deteriorates, the difference in the amount of emitted thermoelectrons (e ₂
It can be understood that the current is reduced by an amount corresponding to −e ₃ ) and a sufficient output cannot be obtained.

Therefore, in order to prevent the deterioration of the electrodes, FIG.
At a sufficient thermoelectron generation temperature T _Three Period to become
Between (0-t_Two ), 0.3 to 1 second, preferably 0.5 second
Before and after to delay applying high voltage between electrodes
It is effective to do.

Based on such knowledge, the applicant of the present application has previously disclosed in Japanese Patent Application No. 11-0119313 a lighting circuit capable of suppressing electrode deterioration and extending the life of a discharge lamp such as a fluorescent lamp. did. The lighting circuit includes a thermoelectron generation circuit that supplies a heating current to each of a pair of electrodes of the discharge lamp, and a main discharge circuit that applies a high voltage between the pair of electrodes. A timer switch is provided which starts when the generation circuit is turned on and turns on the main discharge circuit after a predetermined delay time has elapsed. With such a configuration, a predetermined delay time elapses (time lag) after the thermoelectron generation circuit is turned on, and the high voltage main discharge circuit is turned on only after sufficient thermoelectrons are emitted. Therefore, it has become possible to suppress the deterioration of the electrode.

However, in that case, a stable operation of the timer switch for forming the above-mentioned time lag is expensive, and a lighting circuit using the same is required to obtain approval of safety standards for electrical products. Is expected to take a considerable period of time.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above point of view, and an object thereof is to use a conventionally known glow starter instead of the above timer switch. 11-11-1931
An object of the present invention is to provide a lighting circuit capable of securing the same operation as the lighting circuit disclosed in No. 3, thereby suppressing deterioration of the electrodes and extending the life of a discharge lamp such as a fluorescent lamp.

[0009]

The object of the present invention is to provide a thermionic generating circuit for supplying a heating current to each of a pair of electrodes of a discharge lamp, a main discharge circuit for applying a high voltage between the pair of electrodes, And a glow starter connected in parallel with the discharge lamp in the main discharge circuit. Still further, the above object is to provide a thermionic generating circuit for supplying a heating current to each of a pair of electrodes of a discharge lamp, a main discharge circuit for applying a high voltage between the pair of electrodes, and a primary side of the main discharge circuit. , And a momentary switch connected in parallel with the discharge lamp and interlocked with the alternate switch, which can also be achieved by a discharge lamp lighting circuit.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment in which a discharge lamp lighting circuit according to the present invention is applied to a copper-iron type (for 110 W) ballast for one fluorescent lamp, and FIG. FIG. 3 is a circuit diagram showing an embodiment applied to an iron type (110 W × 2) ballast, FIG. 3 is a circuit diagram showing an embodiment applied to an inverter-type electronic ballast, and FIG. 4 is an electronic ballast without a filament transformer. Circuit diagram showing an embodiment applied to a vessel,
FIG. 5 is a circuit diagram showing an embodiment using a mechanical switch.

First, referring to the embodiment of FIG. 1, reference numeral 1 denotes a fluorescent lamp, 11 and 12 denote electrodes which also function as filaments at both ends of the fluorescent lamp, and 2 denotes a ballast. In ballast 2, T
r is a leakage transformer, F ₁ and F ₂ are filament windings thereof, L ₁₁ is a primary winding for 100 V, L ₁₂ is 200 V
The primary winding, L ₂ is a secondary winding, C ₁ is the resonance capacitor, C ₂ is fast for capacitors, C ₃ is the noise prevention capacitor for use, R is the discharge resistor 20 is a power switch, 21 is a glow starter. Incidentally, glow starter 21 itself, in the case of built-in condenser for noise prevention, the capacitor C ₃ good not be provided (the point is the same in the embodiment shown in FIG. 2). In this circuit, the filament windings F ₁ and F ₂ of the leakage transformer Tr constitute a thermoelectron generation circuit, and the secondary winding L _{2 of the} leakage transformer Tr and the capacitors C ₁ , C ₂ , C ₃ and The discharge resistors R and the like constitute a main discharge circuit.

A user turns on the power switch 20 of the fluorescent lamp.
Then, the primary winding L of the leakage transformer Tr₁₁Or
L₁₂Current flows through the filament winding F₁ , F_Two Output
The electrodes 11 and 12 of the fluorescent lamp are heated by the electric current,
The child is radiated. At the same time, the leakage transformer
Secondary winding L of Tr_Two And the condenser C ₁ , C_Two , C
_Three And the main discharge circuit composed of the discharge resistor R, etc.
Also generates an output voltage, and a high voltage is applied between the electrodes 11 and 12 of the fluorescent lamp.
Pressure is applied to the glow starter 21 at the same time.
Glow discharge generates a glow discharge
The heat causes the built-in bimetal to stretch and
Touch, the current of the main discharge circuit
And the amount of thermoelectrons in the tube of the fluorescent lamp is still
Insufficient and early glow discharge area
The tube voltage is further reduced and becomes almost 0 V at the time of bimetal contact.
Discharge between the fluorescent lamp electrodes 11 and 12
There is no. However, after about one second,
The bimetal in the heater 21 is cooled and the contact is released.
Then, the current flowing through the glow starter is cut off,
At that time, the amount of thermoelectrons in the fluorescent lamp tube was sufficient.
As a result, a high voltage of the power supply is applied and discharge starts, and the tube voltage drops.
The glow starter will not work again. In addition,
When the lamp is new, the fluorescent lamp lights up during glow discharge.
In some cases, discharge occurs at low voltage,
Degradation is reduced. Deterioration of electrodes has progressed and bimetal is one
If it does not light up until it turns off,
You.

As described above, in the present invention, when the quantity of thermionic electrons is insufficient, the current of the main discharge circuit flows through the glow starter 21 and the high voltage current flows between the electrodes 11 and 12 of the fluorescent lamp. Therefore, the electrode surface is not deteriorated by the sputtering, and the life of the fluorescent lamp is extended. Further, since the glow starter itself has been widely used, it is inexpensive and has no problem in terms of safety standards.

The main difference between the lighting circuit of the present invention and the conventional glow lighting system is that the conventional glow lighting system obtains a discharge starting voltage by using a kick voltage generated by switching off. According to the present invention, the glow starter is provided at a position where the voltage applied to the fluorescent lamp is reduced or set to 0 V in the instantaneous lighting circuit which can be lighted without the light emitting device.

FIG. 2 shows an embodiment in which the present invention is applied to a copper-iron (110 W × 2) ballast for two fluorescent lamps. In the drawing, 1A and 1B represent fluorescent lamps, and 11 to 14 represent fluorescent lamps. Electrodes which also serve as filaments at both ends of the fluorescent lamp, 2 are ballasts. In the ballast 2, Tr is a leakage transformer, F ₁ , F
_2, F ₃ is the filament winding, L ₁₁ is the primary winding, L
₂ is a secondary winding, C ₁ is a starting capacitor, C ₂ is a phase leading capacitor, C ₃ is a noise preventing capacitor, R
₁ and R ₂ are discharge resistors, 20 is a power switch, 21
A and 21B are glow starters. In this circuit, the filament winding F of the leakage transformer Tr is used.
₁ , F ₂ and F ₃ constitute a thermoelectron generating circuit, and the secondary winding L _{2 of the} leakage transformer Tr and the capacitors C ₁ and C ₂
C ₂ and C ₃ and discharge resistors R ₁ and R ₂ constitute a main discharge circuit.

The operation of this circuit is also the same as that shown in FIG. 1, and the glow starter 21 inserted between both ends of the fluorescent lamps 1A and 1B in the main discharge circuit, or inserted between both ends of the secondary coil. The time lag is formed by the provided glow starter, and a high voltage current does not flow between the electrodes 11 and 12 and between the electrodes 13 and 14 until sufficient thermoelectrons are emitted into the tubes of the fluorescent lamps 1A and 1B. ,
The deterioration of the electrode surface can be prevented, and the life of the fluorescent lamp can be extended.

FIG. 3 shows an inverter type electronic safety device according to the present invention.
It is a circuit diagram showing an example applied to a constant meter. In the figure, 31
Is an inverter circuit, 32 is a lighting circuit, and 1 is a fluorescent light.
Lamps, 11 and 12 are their electrodes, and 15 is for initial micro-discharge generation.
Ground conductor, Tr is transformer, F ₁ , F_Two Is that filament
The winding 21 is a glow starter. Gloucester
The user turns on the fluorescent lamp and the filter 21
Lament winding F₁ , F_TwoAbout 1 second after the output current is generated
The electrodes 11 and 1 of the fluorescent lamp
No discharge occurs between the two, and sufficient thermoelectrons are emitted during that period.
Will be issued. After that, the glow starter 21 is shut off.
Then, a discharge is generated between the electrodes 11 and 12 to light up.

FIG. 4 shows an embodiment in which the present invention is applied to an electronic ballast without a filament transformer. In the drawing, reference numeral 22 denotes a high-voltage power supply. In this circuit, capacitor C ₄ is (it may not) has the impedance even by passing a current constantly to the filament 11 and 12 may maintain the high voltage (tube voltage), the impedance of C ₅ is smaller than that When the glow starter 21 is in a conductive state at an initial stage, an overcurrent flows through the filaments 11 and 12 to lower the tube voltage (the thermoelectron generating circuit is on) and a predetermined time lag. When the glow starter 21 is cut off at the time when the filament has been sufficiently heated after the elapse of the period, a high voltage is applied between the filaments 11 and 12 (that is, the main discharge circuit is turned on), and the filament current reaches the minimum current. Configure to fall.

FIG. 5 shows an embodiment using a mechanical switch, and shows an example using a momentary switch 24 interlocked with an alternate switch (for a main switch) 23 instead of the glow starter 21 in FIG. ing. The alternate switch 23 is a switch that switches between ON and OFF each time the user pulls the switch string once (or presses the switch button once), and the momentary switch 24 is a switch that the user operates the switch string. Is a switch that is turned ON only during a period in which is pulled (or a period in which the button is pressed). When the user pulls the string of the alternate switch 23 for lighting, the alternate switch 23
Is turned ON, and the momentary switch 24 associated therewith is also turned ON only while the string is being pulled. Therefore, as in the case of FIG. 4, when the momentary switch 24 is in the ON state, the filament 1
When the tube voltage is lowered by the overcurrent flowing to the terminals 1 and 12 (thermionic generation circuit is in the ON state), and after a short time (time lag), the user releases the string, and the momentary switch 24 is turned off. (Alternate switch 2
3 is kept in the ON state), a high voltage is applied between the filaments 11 and 12 (that is, the main discharge circuit is turned on), the fluorescent lamp is turned on, and the filament current is reduced to the minimum current. Note that it is also possible to use a composite of a glow starter and other parts, and it is also possible to provide a plurality of momentary switches for one alternate switch and to simultaneously turn on multiple lights. .

It should be noted that the present invention is not limited to the above embodiment, but can be applied to the lighting of discharge lamps other than fluorescent lamps. Are possible as well as those of the copper-iron type, so that the invention covers within its scope all modifications that can be easily conceived by a person skilled in the art from the above description. .

[0021]

Since the present invention is constituted as described above, according to the present invention, it is possible to provide a method and a circuit for lighting a discharge lamp having little deterioration of electrodes and having a long service life. The effect of the present invention is great in a quartz tube to be irradiated or a compact lamp with a built-in discharge circuit. In addition, the mechanical switch can be easily and effectively used for an inverter-type desk lamp. Further, since the present invention uses a glow starter or a mechanical switch which has been widely used conventionally, it can be produced at low cost and has no problem in safety standards.

[Brief description of the drawings]

FIG. 1 shows a discharge lamp lighting circuit according to the present invention comprising a fluorescent lamp 1;
It is a circuit diagram showing the example applied to the copper iron type (for 110W) ballast for lights.

FIG. 2 is a circuit diagram showing an embodiment applied to a copper-iron ballast for two fluorescent lamps.

FIG. 3 is a circuit diagram showing an embodiment applied to an inverter type electronic ballast.

FIG. 4 is a circuit diagram showing an embodiment applied to an electronic ballast without a filament transformer.

FIG. 5 is a circuit diagram showing an embodiment using a mechanical switch.

FIG. 6 is a graph showing a relationship between electrode temperature and time at the time of starting.

FIG. 7 shows the relationship between the ultimate temperature of the electrode and the amount of generated thermoelectrons.
5 is a graph showing a comparison between a case where the electrode is normal and a case where the electrode is deteriorated.

[Explanation of symbols]

1 fluorescent lamp 11 to 14 electrodes (filaments) 2 ballast 20 power switch 21 glow starter 22 high voltage power supply 23 Alter Nate switch 24 momentary switch Tr transformer F ₁ to F ₃ filament windings L _11, L ₁₂ 1 winding L ₂ Secondary winding

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K083 AA45 BA05 BA13 BA25 BB02 BB05 BB14 BB16 BC03 BC20 CA38

Claims (2)

[Claims] A pair of electrodes (11, 1) of a discharge lamp (1).
A thermionic generator for supplying a heating current to each of _{2) (F 1, F 2} ), the main discharge circuit (L ₂ for applying a high voltage between the pair of electrodes (11,12), C _1, C ₂ , C
_And a glow starter (21) connected in parallel with the discharge lamp (1). A discharge lamp lighting circuit (2). 2. A pair of electrodes (11, 1) of a discharge lamp (1).
A thermionic generator for supplying a heating current to each of _{2) (F 1, F 2} ), the main discharge circuit (L ₂ for applying a high voltage between the pair of electrodes (11,12), C _1, C ₂ , C
₃ , R), an alternate switch (23) provided on the primary side of the main discharge circuit, and a momentary switch (24) connected in parallel with the discharge lamp (1) and interlocked with the alternate switch (23). A lighting circuit for a discharge lamp, comprising: