JP2007273343A - Fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and low-cost fluorescent lamp lighting device capable of preventing appearance degradation by contact between lead wires. <P>SOLUTION: This fluorescent lamp 100 is provided with: an arc tube 14 having filament electrodes 14a and 14b; and a choke coil 11 for preheating the filament electrodes 14a and 14b by carrying a current supplied to a primary winding 111 through FETs 5 and 6 being switching elements to the filament electrodes 14a and 14b through magnetically-coupled preheating secondary windings 122 and 123. The primary winding 111 and the preheating secondary winding 122, and the primary winding 111 and the preheating secondary winding 123 are respectively arranged within an extremely close range, and the wire diameter of the preheating secondary winding is not greater than 0.14 mm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light bulb type fluorescent lamp, and more particularly to a circuit interruption technique when a lead wire is in contact with a preheated light bulb type fluorescent lamp.

  In recent years, an inverter type has dominated as a light bulb type fluorescent lamp (hereinafter referred to as “fluorescent lamp”). The inverter method is a method of once converting AC power supplied from an AC power source into DC power, then converting it to high frequency power of 30 to 100 kHz, supplying power to the arc tube, and lighting the arc tube. Compared with the magnetic circuit type, there is an advantage that the luminous efficiency is high and the lighting circuit can be reduced in weight.

In the inverter method, when the fluorescent lamp is started, the arc tube electrode is heated by a preheating circuit, and at the same time, a voltage having a large amplitude due to resonance is applied between the arc tube electrodes, and this voltage is applied to the arc tube start voltage. When it becomes higher, discharge starts in the arc tube, and the arc tube is turned on (Patent Document 1).
On the other hand, in a fluorescent lamp, lead wires that are led out from the respective electrodes of the arc tube and connect the respective electrodes and the preheating circuit may be arranged at positions where they are easily contacted.

In such a case, if the lead wires are in contact with each other, in the preheating circuit, the contact lead wires become a heating element, and the case may be discolored or deformed by the heat, and the appearance may be damaged. is there.
In particular, as described in Patent Document 2, in the case of a fluorescent lamp having a spiral arc tube, the connecting pins on the circuit board for connecting each lead wire to the preheating circuit are arranged close to each other. Therefore, when connecting each pair of lead wires led out from both ends of the spiral arc tube to the corresponding connecting pins, the lead wires are likely to contact each other.

For this reason, in the fluorescent lamp, various protective measures against the contact between the lead wires are taken.
For example, a lead wire is coated with an insulating material such as silicone or glass.
Thereby, since a lead wire is insulated with an insulating material, it can prevent a lead wire from becoming a heat generating body.

Further, depending on the fluorescent lamp, a negative temperature characteristic resistance element (NTC) is inserted into the preheating circuit.
As a result, even if the lead wires become a heating element due to contact between the lead wires, the electrical resistance of the preheating circuit is reduced with the temperature rise by NTC, and the lead wires can be prevented from being overheated.

Moreover, in patent document 2, it arrange | positions so that each connection pin on a circuit board may not adjoin, and it prevents that lead wires contact.
Japanese Patent Laid-Open No. 10-79298 Japanese Patent Application No. 2003-580767

However, if lead wires are covered with an insulating material or NTC is inserted into a preheating circuit in order to prevent appearance deterioration due to contact between the lead wires, extra parts cost is required and the number of manufacturing steps increases. The problem arises.
Further, as in Patent Document 2, there is a problem that contact between the paired lead wires cannot be prevented only by arranging the connecting pins to face each other.

  In view of the above problems, an object of the present invention is to provide a fluorescent lamp lighting device that can prevent deterioration in appearance due to contact between lead wires in a simple and low cost manner.

  In order to achieve the above object, the present invention includes an arc tube having a filament electrode, a primary winding, and a secondary winding magnetically coupled to the primary winding, and the primary winding is connected to the primary winding via a switching element. A fluorescent lamp comprising a preheating coil unit that preheats the filament electrode by flowing a supplied current to the filament electrode through the secondary winding, wherein the primary winding and the The secondary winding is disposed within a short distance, and the secondary winding is a winding having a wire diameter of 0.14 mm or less.

In the preheating coil unit, the primary winding and the secondary winding may be adjacently wound around a common core.
The secondary winding may have a length of at least 100 mm.

  In the fluorescent lamp having the above configuration according to the present invention, the secondary winding has a thin wire diameter (0.14 mm or less), and when the lead wires connected to the filament electrode come into contact with each other, the secondary winding Therefore, the time until the primary winding 111 within a short distance from the secondary winding is rarely short-circuited by heat can be shortened by the amount of heat generation.

  As a result, after contact between the lead wires, a large current is generated in a short time, which flows into the switching element, destroys the switching element, and can stop the preheating operation. It is possible to prevent discoloration or deformation by being heated for a long time by the lead wire that becomes a body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment)
<Configuration>
FIG. 1 is a partially cutaway front view (FIG. 1A) and a bottom view (FIG. 1B) of a fluorescent lamp 100 in the present embodiment. FIG. 2 is a development view of the fluorescent lamp 100. A fluorescent lamp 100 shown in FIG. 1 and FIG. 2 is a 22 W type light bulb type fluorescent lamp for 100 W type incandescent lamp replacement.

The fluorescent lamp 100 includes an arc tube 14 whose discharge path is curved in a spiral shape, a holder 25 for holding the arc tube 14, a lighting circuit unit 50 in which circuit components for lighting the arc tube 14 are arranged on a circuit board, a base, The resin case 30 is attached to the housing 40 and holds the holder 25 and accommodates the lighting circuit unit 50.
(Arctube 14)
A glass tube made of soft glass (for example, outer diameter φ: 9.0 mm) is folded at a substantially central portion, and both ends are sealed.

The arc tube 14 is formed by bending a glass tube coated with a phosphor on the inner surface of the tube, and has a double spiral structure in which a portion other than the substantially central portion is bent in a spiral shape so as to overlap each other in the same direction. Both ends of the glass tube are bent along the spiral direction.
The glass tube is filled with an inert gas (for example, 100% argon gas) at 500 Pa, and filament electrodes (not shown) made of filament coils are provided at both ends of the glass tube. Respectively, a pair of lead wires 101 and 102 (here, Fe, Ni, Cr alloy (alloy composition: Fe52Ni42Cr6, outer diameter φ: 0.4 mm) are used as the lead wires) holding the filament electrodes. ) Has been derived.

Each lead wire led out is sealed and fixed to the glass tube by melting the glass tube.
The pair of lead wires may be in contact with each other in an assembly process of the fluorescent lamp 100 or the like.
The discharge path length between both electrodes is set to about 700 mm.
(Holder 25)
It is made of a resin material such as LCP (Liquid Crystal Polymer), and as shown in FIG. 2, has a shape on a plate, and includes a bottom surface 26 and an outer peripheral wall 27 provided in a wall shape at the edge of the plate. .

The bottom surface 26 is formed with insertion holes (25a and 25b in FIG. 2) that engage with the shapes of the regions in the vicinity of both ends of the arc tube 14, respectively.
After the regions near both ends of the arc tube 14 are inserted into the respective insertion holes, the gap formed in the insertion holes is filled with silicone resin and fixed to the holder 25.
Further, as shown in FIG. 2, holes 221 that engage with protrusions 52 provided on a circuit board 51, which will be described later, are formed in the outer peripheral wall 27 at four locations. There are two protrusions 222 (resin case) that engage with the combination hole 32 (in FIG. 2, only one is shown due to restrictions on drawing, but there are actually two). 30)
It is made of a resin material such as PET (polyethylene terephthalate), has a funnel shape as shown in FIG. 2, a base 40 is attached to the top of the resin case 30, and an inner peripheral surface 31 has a holder 25. A hole 32 that engages with each protrusion 222 is formed.

The holder 25 is fixed to the resin case 30 by inserting the holder 25 from the opening side of the resin case 30 and fitting the protrusion 222 of the holder 25 with the hole 32.
(Lighting circuit unit 50)
A plurality of components such as capacitors, transistors, and choke coils are mounted on a circuit board 51 on which wiring of a predetermined pattern is formed.

The circuit board 51 is provided with protrusions 52 that are engaged with the respective holes 221 of the holder 25 at four positions on the edge portion, and led out from both ends of the arc tube 14 at the other two positions on the edge portion. A notch 53 is provided for locking each pair of lead wires.
Further, a pair of connecting pins 54 a and 54 b for connecting to the lead wires are provided upright on the periphery of each notch 53.

The connection pins 54a and 54b are made of a conductive material, and each lead wire led out from the arc tube 14 is electrically connected to the wiring formed on the circuit board 51 by being individually wound around each connection pin. Is done.
(Configuration of lighting circuit)
FIG. 3 is a diagram showing a circuit configuration of the lighting circuit of the fluorescent lamp 100 formed by electrically connecting the arc tube 14 to the lighting circuit unit 50 via a pair of lead wires 101 and 102. is there.

Reference numeral 1 denotes an AC power source. As the AC power source 1, for example, a power source supplied from a household outlet can be used, and an AC voltage having an effective value of 100 V is output to the rectifier circuit 3.
The capacitor indicated by reference numeral 2 constitutes an inductor and a filter circuit indicated by reference numeral 19 and blocks the noise of the AC power supply 1.
Reference numeral 3 denotes a rectifier circuit, which converts AC power output from the AC power source 1 into DC power. A negative temperature characteristic resistance element (NTC) indicated by reference numeral 22 is connected to the rectifier circuit 3.

Reference numeral 4 denotes a smoothing capacitor which receives a direct current, accumulates electric charge, and reduces a rumble current.
Reference numerals 5 and 6 denote switching elements, that is, N-channel FET (field effect transistor) (hereinafter referred to as “FET5”) and P-channel FET (hereinafter referred to as “FET6”), respectively. Are alternately turned on, a current flows through the choke coil indicated by reference numeral 11, the electrodes 14a and 14b of the arc tube 14 indicated by reference numeral 14 are preheated, and constitute a resonance circuit with the choke coil 11. When the voltage across the capacitor increases and becomes higher than the starting voltage of the arc tube 14, dielectric breakdown occurs in the arc tube 14, discharge starts, and the negative resistance of the arc tube 14 causes a discharge from the lighting circuit. The supply current is limited and the discharge is maintained.

A series circuit of a Zener diode indicated by reference numeral 20 and a Zener diode indicated by reference numeral 21 connected in reverse polarity is connected between the gate and source of the FET 5.
Further, a resistor 9 and a capacitor 23 are connected in parallel between the drain and source of the FET 6.
FIG. 5 shows the winding structure of the choke coil 11. Reference numeral 60 in FIG. 5 indicates a core (for example, a ferrite core), reference numeral 111 in FIG. 5 indicates a primary winding indicated by the same reference numeral in the circuit configuration of FIG. 3, and reference numeral 112 in FIG. 5 indicates a step-up winding indicated by the same reference numeral, reference numeral 121 in FIG. 5 indicates a secondary winding indicated by the same reference numeral in the circuit configuration in FIG. 3, and reference numeral 122 in FIG. 5 shows a preheating secondary winding indicated by the same reference numeral in the circuit configuration, reference numeral 123 in FIG. 5 shows a preheating secondary winding indicated by the same reference numeral in the circuit configuration of FIG. 3, and reference numeral 61 in FIG. 5 shows an insulating tape. .

The preheating secondary winding 122, the primary winding 111, the step-up winding 112, the preheating secondary winding 123, the insulating tape 61, and the secondary winding 121 are wound around the core 60 in this order in the same direction. The winding start portion and winding end portion of the are connected to a connection terminal (not shown) and connected to the lighting circuit via the connection terminal.
The number of turns of each winding here is 4 turns for the preheating secondary winding 122, 105.5 turns for the primary winding 111, 30.5 for the boosting winding 112, 4 turns for the preheating secondary winding 123, 2 turns. The next winding is 4.5 turns.

As the material of each winding, for example, copper can be used, and the surface of each winding is covered with an insulating coating (for example, polyester-nylon coating, polyurethane coating, polyester coating, polyesterimide coating, etc.).
The diameters of the respective windings are 0.03 to 0.14 mm for the preheating secondary windings 122 and 123, 0.12 mm for the primary winding 111, 0.2 mm for the step-up winding 112, and 0.2 for the secondary winding 121. 2 mm.

  In the circuit stop operation at the time of the lead wire contact described later, the lighting circuit is stopped in a short time by causing the primary winding 111 and the step-up winding 112 to be quickly short-circuited, and an appearance abnormality appears in the fluorescent lamp. In order to prevent this, the wire diameter of the preheated secondary winding may be 0.14 mm or less and may be smaller than 0.03 mm. However, in order to maintain the strength necessary for handling the winding, A wire diameter of at least 0.03 mm is necessary.

Further, the wire diameter of the primary winding 111 is not limited to the above case, and may be larger or smaller than 0.12 mm. The same applies to the wire diameters of the booster winding 112 and the secondary winding 121.
In addition, the length of the preheating secondary winding for obtaining the above-described prevention effect may be approximately 100 mm or more from the results of Examples described later.

When FET 5 and FET 6 are alternately turned on, when a current flows through the choke coil 11, a current flows through the primary winding 111, and a voltage is induced across the boost winding 112 that is electromagnetically coupled to the primary winding 111. Then, the voltage of the step-up winding 112 is applied to the light emitting lamp 14 in addition to the voltage across the capacitor 12.
Thereby, it is possible to supply electric power necessary for maintaining lighting to a fluorescent lamp that requires a high voltage like the fluorescent lamp of the present embodiment.

Further, when a current flows through the primary winding 111, a voltage is induced at each end of the preheating secondary windings 122 and 123 magnetically coupled to the primary winding 111, and by this voltage, each filament electrode 14a of the arc tube 14 is induced. And 14b, a current flows and both filament electrodes are preheated.
Reference numerals 7, 8, 18, and 24 denote resistances.
The resistor 18 is a resistor for preventing a large current from flowing from the AC power supply 1 to the lighting circuit, and the resistor 24 is a leakage of the fluorescent lamp, contamination of impure gas into the fluorescent lamp, the end of life of the fluorescent lamp, etc. In addition, when the voltage in the fluorescent lamp rises and a large current flows in the lighting circuit, the switching element is connected in series with the FET 5 as shown in FIG.

Reference numeral 17 denotes a coupling capacitor, which cuts a DC component from the flowing current.
Next, the preheating operation by the lighting circuit will be described.
(Preheating operation)
When the converted DC power is simultaneously supplied to the resistors 7, 8, 9, a voltage corresponding to the resistance value of each resistor is generated at both ends of each resistor, and the N channel is generated by the voltage generated at both ends of the resistor 8. The switch of the FET 5 (hereinafter referred to as “FET 5”) is turned on, and charge is accumulated in the trigger capacitor indicated by reference numeral 10.

When the voltage across the trigger capacitor 10 reaches the threshold voltage of the FET 5, the charge accumulated in the trigger capacitor 10 is supplied to the gate of the FET 5, and the switch of the FET 5 is turned on.
When the FET 5 is switched on, current flows from the anode side of the smoothing capacitor 4 through the primary winding 111 of the FET 5 and the choke coil 11, and the capacitor 12 constituting the resonance circuit with the choke coil 11 and the reference numeral 13. It flows through a positive temperature characteristic resistance element (PTC).

  When a current flows through the primary winding 111, a voltage is induced at each end of the secondary winding 121 of the choke coil 11 and the preheating secondary windings 122 and 123 that are magnetically coupled to the primary winding 111. The voltage between the gate and the source of the FET 5 is increased, the switch of the FET 5 is kept on, and a current flows from the preheating secondary windings 122 and 123 to the filament electrodes 14a and 14b of the arc tube 14, and each filament electrode Is preheated.

Thereafter, the polarity of the current flowing through the secondary winding 121 is reversed by the resonance of the inductor connected to the secondary winding 121 and the capacitor 15 shown in FIG. Then, it starts to flow in the reverse direction, the voltage between the gate and source of the FET 5 becomes smaller than the threshold voltage, and the switch of the FET 5 is turned off.
On the other hand, when the current flowing through the secondary winding 121 flows in the reverse direction, the voltage between the gate and the source of the FET 6 increases, and the switch of the FET 6 is turned on.

  When the switch of the FET 6 is turned on, the electric charge accumulated in the capacitor 12 is supplied to the primary winding 111 and the FET 6, and a current flows. This current is a series resonant circuit constituted by the capacitor 12 and the primary winding 111. The voltage is induced at both ends of the secondary winding 121 and the preheating secondary windings 122 and 123 that are magnetically coupled to the primary winding 111 and the voltage between the gate and the source of the FET 6 is increased. The switches of the FET 6 are kept on and current flows from the preheating secondary windings 122 and 123 to the filament electrodes 14a and 14b of the arc tube 14 to preheat each filament electrode.

Thereafter, the current flowing through the secondary winding 121 is reversed in polarity due to resonance of the capacitor 16 that is connected to the secondary winding 121 and constitutes a resonance circuit with the inductor 15 and the inductor 15. The voltage between the gate and the source of the FET 6 becomes smaller than the threshold voltage, and the switch of the FET 6 is turned off.
On the other hand, when the current flowing through the secondary winding 121 flows in the reverse direction, the voltage between the gate and the source of the FET 5 increases, and the switch of the FET 5 is turned on.

In this way, when the switches of the FETs 5 and 6 are alternately turned on, a current flows continuously through the primary winding 111, a voltage is induced at each end of the preheating secondary windings 122 and 123, and the preheating secondary Current continuously flows from the windings 122 and 123 to the filament electrodes 14a and 14b of the arc tube 14, and each filament electrode is preheated.
(Circuit stop operation)
Next, the operation of stopping the lighting circuit when a pair of lead wires 101 and 102 are in contact with each other will be described.

  In the pair of lead wires 101, when the paired lead wires are in contact with each other, current does not flow to the filament electrode 14a. Therefore, the resistance value of the preheating circuit is smaller than that in the non-contact state, and the lead in contact state The amount of current flowing through the wire pair 101 and the preheating secondary winding 122 is increased, and the amount of heat generated in the lead wire pair 101 and the preheating secondary winding 122 is larger than that in the non-contact state.

  When the amount of heat generated in the preheating secondary winding 122 increases, the primary winding 111 adjacent to the preheating secondary winding 122 is heated as shown in FIG. The primary winding 111 is heated in a chain by the heated primary winding 111, and the insulation coating on the surface of the primary winding 111 and the boosting winding 112 is melted, and the primary winding 111 and the boosting winding 112 are rarely short-circuited. However, the inductance of the primary winding 111 and the boosting winding 112 is reduced, the impedance is reduced, and a large current flows through the switching element connected in series with the primary winding 111 and the boosting winding 112, so that the switching element is destroyed. Then, the lighting circuit stops.

  Similarly, even when the lead wires of the other lead wire pair 102 are in contact with each other, as shown in FIG. 5, the booster winding 112 adjacent to the preheating secondary winding 123 is heated, Further, the primary winding 111 adjacent to the heated step-up winding 112 is chain-heated, and eventually the insulation coating on the surface of the step-up winding 112 and the primary winding 111 is melted, and the step-up winding 112 and the primary winding are melted. The windings are short-circuited, a large current flows through the switching elements connected in series with the booster winding 112 and the primary winding 111, the switching elements are destroyed, and the lighting circuit is stopped.

  FIG. 6 is an image diagram showing the state of the surface of each winding in the portion where the preheating secondary winding 122 and the primary winding 111 are adjacent, indicated by 62 in FIG. 6 shows the state of the surface of the preheating secondary winding 122 and the primary winding 111 when the lead wires are in a non-contact state. Reference numeral 70 denotes a conductive member (for example, copper wire) of each winding, and reference numeral 71 denotes an insulating film covering the conductive member.

  6 shows the state of the surface of the preheating secondary winding 122 and the primary winding 111 when the lead wires are in contact with each other. In the figure on the right side, the preheating secondary winding 122 generates excessive heat due to the contact between the lead wires, and the insulating film covering the conductive member of each winding is melted by the heat, and the preheating secondary winding is melted. It shows that the wire 122 and the primary winding 111 are in a short-circuited state.

  Here, if it takes time until the primary winding 111 and the step-up winding 112 are rarely short-circuited, the lighting circuit is not stopped, and the lead wire pair 101 in a contact state continues to generate heat during that time, and the heat is supplied to the holder 25. In the present invention, the resistance of the preheating secondary windings 122 and 123 is reduced by reducing the wire diameter of the preheating secondary windings 122 and 123 (0.14 mm or less). The value is increased to increase the amount of heat generated when the lead wire contacts.

Thereby, after the lead wires of the lead wire pair 101 or 102 contact each other, the time until the primary winding 111 and the step-up winding 112 are rare-shorted can be shortened, and the lighting circuit can be stopped in a short time. The holder 25 and the case 50 can be prevented from being discolored or deformed by being heated for a long time by the heated lead wire pairs 101 and 102.
(Example)
(Lead wire miscontact test)
(Test method)
The diameter of the preheating secondary windings 122 and 123 of the fluorescent lamp 100 is set to 0.10 to 0.20, and the fluorescent lamp 100 is in a state in which the lead wires are miscontacted in any of the lead wire pairs 101 and 102. The AC voltage was supplied to the lamp, and the time until the lighting circuit was stopped after the supply of the AC voltage was started was measured, and the appearance of the fluorescent lamp 100 when the lamp was stopped was observed.

(Lead wire components)
Alloy whose alloy composition is Fe52Ni42Cr6, wire diameter 0.4mm
(Lighting circuit components)
AC power supply 1: 100 V, choke coil 11: 850 μH (primary winding 111: number of turns 105.5, wire diameter 0.12 mm, length 2400 mm (approximate value)), (secondary winding 121: number of turns 4.5 , Wire diameter 0.20 mm, length 113 mm (approximate value)), (boost winding 112: number of turns 30.5, wire diameter 0.20 mm, length 766 mm), (preheating secondary winding 122, 123: turn 4.0, wire diameter 0.10 to 0.20 mm, length 100 mm), inductor 15: 680 μH, inductor 19: 47 μH, resistor 7: 1/4 W, 2 MΩ, NTC 22: 4Ω, PTC 13: 1 kΩ, resistor 8: 1/8 W, 150 KΩ, resistor 9: 1/4 W, 150 KΩ, resistor 18: 1/2 W, 1Ω, resistor 24: 1/4 W, 1Ω, capacitor 2: 0.039 μF, smoothing capacitor 4: 27 μF, capacitor 10: 0 .12μF , Capacitor 12: 8200 pF, capacitor 16: 3300 pF, capacitor 17: 0.1 μF, capacitor 23: 220 pF, FET5, 6; drain-source voltage (VDS) = 0.2 kV, Zener diode 20, 21: Zener voltage = 10V
In addition, the material of each said winding is copper, and the insulation film which coat | covers the surface of each winding is polyester nylon.

Moreover, the primary winding 111 uses a stranded wire (so-called litz wire) obtained by twisting a plurality of (three or four) copper wires, and the wire diameter shown above is the wire diameter of each twisted copper wire. Represents. Here, the number of copper wires to be twisted can be five or six.
(Test results)
FIG. 4 shows the test results of the lead wire miscontact test. As shown in FIG. 4, when the wire diameter of the preheating secondary winding is 0.16 mm or more, the appearance is abnormal (specifically, a part of the holder 25 is melted), and is 0.14 mm or less. No abnormalities were observed in the appearance.

Also, the time until the lighting circuit is stopped is immediately after the AC voltage supply starts when the wire diameter is 0.10 to 0.12 mm, and 16 to 60 seconds when the linear is 0.14 mm. In the case of 0.16 mm or more, it was 30 to 10,800 seconds.
Further, in all wire diameters, the choke coil 11 when the circuit was stopped was in a rare shorted state.
(Supplement)
Although the present invention has been described based on the embodiments, it is needless to say that the present invention is not limited to the above embodiments.
(1) In this embodiment, the 22W type fluorescent lamp has been described as an example. However, the present invention can be applied not only to the 22W type but also to other types (for example, 12W type). Also, the arc tube is not limited to a spiral arc tube, and the present invention can be applied to arc tubes having other shapes (for example, U-shape).
(2) Although an example of a light bulb type fluorescent lamp not provided with a globe has been described in the present embodiment, the present invention can also be applied to a light bulb type fluorescent lamp provided with a globe.
(3) The type of the light bulb type fluorescent lamp to which the present invention can be applied is not limited to that of the present embodiment, but other types such as a general light bulb type (A type), a ball type (G type), and a double U type. It can also be applied to (D type), cylindrical (T type), and ring (C type) bulb-type fluorescent lamps.
(4) Although the winding structure shown in FIG. 5 is applied to the choke coil in the present embodiment, it may be applied to a transformer instead of the choke coil.

Further, the winding structure is not limited to the winding structure shown in FIG. 5, but the primary winding 111 or the boosting winding 112 and the preheating secondary winding 122, the primary winding 111 or the boosting winding 112 and the preheating secondary winding. The wire 123 may be a winding structure that is arranged close to each other so that heat can be conducted well.
(5) Although the field effect transistor (FET) is used as the switching element in the lighting circuit in the present embodiment, another switching element, for example, a hyperpolar transistor may be used.

  In this embodiment, two switching elements are used. However, the number of switching elements is not limited to two. For example, one switching element may be used.

  The present invention relates to a light bulb type fluorescent lamp, and in particular, can be used as a circuit interruption technique when a lead wire is contacted in a preheated fluorescent lamp.

FIG. 1 is a partially cut front view (FIG. 1A) and a bottom view (FIG. 1B) of a fluorescent lamp 100. FIG. FIG. 2 is a bottom view (FIG. 1B). 2 is a development view of the fluorescent lamp 100. FIG. 2 is a diagram illustrating a circuit configuration of a lighting circuit of the fluorescent lamp 100. FIG. The test result of the lead wire miscontact test is shown. The winding structure of the choke coil 11 is shown. It is an image figure which shows the state of the surface of each coil | winding in the part which the preheating secondary winding 122 and the primary winding 111 show by 62 of FIG.

Explanation of symbols

1 AC power supply 2, 12, 16, 23 Capacitor Capacitor 3 Rectifier circuit 4 Smoothing capacitor FET
7, 8, 9, 18, 24 Resistance 10 Trigger capacitor 11 Choke coil 13 PTC
14 Arc tube 15, 19 Inductor 17 Coupling capacitor 20, 21 Zener diode 22 NTC
25 Holder 25a, 25b Insertion hole 26 Bottom surface 27 Outer peripheral wall 30 Resin case 31 Inner peripheral surface 32, 221 Hole 40 Base 50 Lighting circuit unit 51 Circuit board 52, 222 Protrusion 53 Notch 54a, 54b Connecting pin 60 Core 61 Insulating tape DESCRIPTION OF SYMBOLS 100 Fluorescent lamp 101,102 A pair of lead wire 111 Primary winding 112 Boosting winding 121 Secondary winding 122,123 Preheating secondary winding

Claims (3)

An arc tube having a filament electrode; a primary winding; and a secondary winding magnetically coupled to the primary winding, wherein a current supplied to the primary winding via a switching element is supplied to the secondary winding. A preheating coil unit that preheats the filament electrode by flowing through the filament electrode through a fluorescent lamp,
In the preheating coil unit, the primary winding and the secondary winding are disposed within a short distance,
The secondary lamp is a coil having a wire diameter of 0.14 mm or less. The fluorescent lamp according to claim 1, wherein in the preheating coil unit, the primary winding and the secondary winding are wound around a common core adjacent to each other. The fluorescent lamp according to claim 2, wherein the secondary winding has a length of at least 100 mm.

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