JP2001284074A - Bulb-shared fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bulb-shaped fluorescent lamp with an inverter circuit which does not operate erroneously even when coupled with a dimmer for light control, reducing the surge current when turned on while restraining the distortion of input current without increasing the number of parts. SOLUTION: For a lighting circuit 15 mounted on a main board installed in a main body, it is so made that charging current to a filter capacitor does not flow until a fluorescent tube 14 starts discharging, and surge current is reduced by the impedance component of the fluorescent lamp 14 even after the start of discharging, by interposing the fluorescent tube 14 in the path between the filtered power supply 22 and the filter capacitor C2. At the combination with a dimmer for phase control, considering the load circuit from power supply, by constructing a serial circuit of a constant current choke L1 and a main switching means 23, electric current is enabled to flow at all time without stop period in the circuit in which electric current flows from power supply to the load, and the dimmer for the phase control is prevented from faulty on-off operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact fluorescent lamp.

[0002]

2. Description of the Related Art Conventionally, there has been known a bulb-type fluorescent lamp in which a fluorescent arc tube and its lighting circuit are housed in a bulb-shaped envelope. Such a bulb-type fluorescent lamp has an E-shaped base that is screwed directly into a socket for an incandescent lamp, and surrounds a lighting circuit that converts a low-frequency alternating current from a commercial power supply into a high-frequency power and supplies power to the fluorescent arc tube. It is prepared in the vessel.

As such a lighting circuit, an electronic ballast using a so-called inverter circuit is often used. That is, after a commercial AC power supply is full-wave rectified by a full-wave rectifier circuit, it is smoothed by a smoothing capacitor, and the smoothed DC voltage is used as a power supply to control the on / off control of a switching element such as a transistor so that the high-frequency output is a fluorescent lamp. The lighting is performed by giving the illuminated light.

With respect to such an inverter circuit, distortion of an input current caused when a pulsating voltage obtained by rectifying an AC voltage is smoothed by a smoothing capacitor, and an inrush current at the time of turning on a power supply is controlled by an impedance element. It is conventionally known to reduce the amount by using.

In the case of incandescent lamps, for example, dimming operation is performed by controlling the phase of an AC power supply using a phase control dimmer using a phase control element such as a triac interposed in a commercial AC power supply line. Some have made it possible.

[0006]

However, with respect to a bulb-type fluorescent lamp used like an incandescent lamp, it is attempted to perform dimming lighting by controlling the phase by the above-described phase control dimmer. Then, the inverter circuit may malfunction. For example, in a capacitor input type smoothing circuit, since the input current has a pause, the current flows only to the filter capacitor when the phase control dimmer is turned on, so the phase control triac turns on and off. Repetitive malfunctions occur, and the light is not flickered at the phase to be flickered, which may cause flickering in the lighting state.

For this reason, an impedance element such as a filter or a snubber is provided in the inverter circuit in order to prevent a malfunction with the phase control dimmer. Requires additional parts. In a bulb-type fluorescent lamp, the space for mounting a lighting circuit including an inverter circuit is limited, so that an increase in the number of parts is not preferable.

According to the present invention, the rush current at the time of turning on the power is reduced while suppressing the distortion of the input current without increasing the number of components, and a malfunction occurs even in dimming control in combination with a dimmer for phase control. It is an object of the present invention to provide a bulb-type fluorescent lamp provided with an inverter circuit that does not have any problem.

[0009]

According to the first aspect of the present invention, there is provided a light bulb-shaped fluorescent lamp according to the invention, a base having a base, a fluorescent light emitting tube mounted on the base, a substrate mounted in the base, and a DC power supply. And a lighting circuit mounted on a substrate including an inverter circuit for generating a high frequency for operating a fluorescent light emitting tube interposed in a closed loop between the light emitting diode and the smoothing capacitor.

In the present invention and each of the following claims, the definitions and technical meanings of terms are as follows unless otherwise specified.

A "bulb-shaped fluorescent lamp" is a device in which a fluorescent luminous tube and its lighting circuit are generally integrated, a base is attached, and the lamp is mounted on a lamp socket adapted to the base. It means a lamp configured to be used as if lighting the lamp.

The "base" is screwed into a socket to which a light bulb such as an incandescent lamp is attached, and a typical one is an Edison base type (E type) socket.

The "substrate" is preferably formed of, for example, an insulating material such as plastic and has no light transmission property or a very weak light transmission property. This is to make the lighting circuit invisible to store and hold a “lighting circuit” described later. However, the present invention is not limited to this, and it may be formed of a material having a light transmitting property.

The "fluorescent light emitting tube" is a so-called fluorescent lamp or metal halide lamp, and its shape is not particularly limited. However, by forming a U-shape or a continuous shape thereof, a compact shape can be obtained while ensuring brightness. The fluorescent tube may be either a low-pressure discharge lamp or a high-pressure discharge lamp.

When the fluorescent tube is a fluorescent lamp which is a low-pressure discharge lamp, a filament is used as an electrode.
In this case, the filament is generally started with a hot cathode and turned on. In such a case, there are, for example, the following two methods for heating the filament at startup.

The first is to connect a resonance capacitor in parallel with the discharge lamp via at least one filament at the time of starting. Then, a current flows through the filament via the current-limiting inductance and the resonance capacitor at the time of starting, so that the filament connected in series with the filament is heated. At the same time, the current-limiting inductance and the resonance capacitor resonate appropriately in series, and the terminal voltage of the resonance capacitor increases, so that the discharge lamp can be started according to the relationship between the filament heating state of the discharge lamp and the applied voltage. Starts.

Second, the filament is heated using a filament heating transformer. The filament heating transformer may be provided separately from the current limiting inductance, but the filament heating winding can be magnetically coupled to the current limiting inductance. This can suppress an increase in the number of circuit components.

The "substrate" is a substrate for mounting a lighting circuit to be described later, and has a shape corresponding to the cross-sectional shape of the base. Usually, a circular substrate is used. Such a substrate preferably has a maximum diameter substantially equal to the maximum width of the fluorescent tube. Because, when the maximum diameter of the substrate is larger than the maximum width of the fluorescent tube, the outer dimension in the width direction of the bulb-type fluorescent lamp becomes larger by that amount, and the maximum diameter of the substrate is smaller than the maximum width of the fluorescent tube. This is because the mounting area of the substrate is reduced.

It is desired that the external dimensions of the bulb-type fluorescent lamp be reduced in size, and the external dimensions are often determined by the dimensions of the relatively large fluorescent tube in the configuration of the bulb-type fluorescent lamp. On the other hand, since a circuit element as a lighting circuit is mounted on the substrate, component mounting becomes easier as the substrate area increases as much as possible.

The "lighting circuit" is a so-called electronic ballast for lighting the fluorescent light emitting tube, and basically has an inverter circuit configuration for converting a DC voltage obtained from a DC power supply into a high-frequency voltage and supplying power to the fluorescent light emitting tube. And The inverter circuit of the present invention is based on the assumption that a DC power supply that rectifies a commercial AC power supply is used to generate a DC voltage using a smoothing capacitor. As a smoothing capacitor,
An electrolytic capacitor is used. Generally, a rectifier such as a full-wave rectifier circuit is used as the DC power supply. Although the inverter circuit itself has various circuit types, it has at least main switching means for performing on / off switching operation. Either a voltage-driven main switching device such as a MOSFET or a current-driven main switching device such as a bipolar transistor may be used. Further, it may be either a single-type inverter circuit having only one switching means or a half-bridge type inverter circuit having a pair of switching means that are turned on and off alternately. In the case of a half-bridge type inverter circuit, one of the pair of switching means is the main switching means.

The "fluorescent light emitting tube interposed in a closed loop between the DC power supply and the smoothing capacitor" means that the DC power supply, the smoothing capacitor and the fluorescent light emitting tube substantially form a series closed loop circuit. And other circuit components such as inductors and resistors may be interposed between them.

Regarding the operation of the present invention With respect to the lighting circuit mounted on the substrate mounted in the base, a fluorescent arc tube is interposed in the charging path from the DC power supply to the smoothing capacitor. The charging current to the smoothing capacitor does not flow until the discharge starts, and even after the discharge starts, the rush current is reduced by the impedance component of the fluorescent tube. Therefore, the rush current can be reduced by devising the connection without separately providing an impedance element. That is, as a result, it is possible to use a smoothing capacitor having a low withstand voltage and to provide a configuration suitable for a compact fluorescent lamp with a small mounting space.

According to a second aspect of the present invention, in the light bulb shaped fluorescent lamp according to the first aspect, the inverter circuit is connected between a DC power supply whose dimming is controlled by phase control and an output terminal of the DC power supply. Main switching means; a series circuit of a ballast choke, a fluorescent light emitting tube, and a smoothing capacitor connected in parallel to the main switching means; and a parallel connection to the ballast choke and the fluorescent light emitting tube to resonate with the ballast choke. A resonant capacitor; and a constant current choke connected to the input side of the main switching means to limit the input current.

In the present invention and the inventions described in the following claims, the definitions and technical meanings of terms are as follows unless otherwise specified.

The inverter circuit in the lighting circuit includes at least a ballast choke (resonance inductor) and a resonance capacitor in addition to the DC power supply and the main switching means. "Ballast choke and resonance capacitor" means LC
It forms a parallel resonance circuit, and operates by alternating current generated by the on / off switching operation of the main switching means. The ballast choke and the resonance capacitor are used when the load has a negative characteristic like a discharge lamp.
Any one of them can be configured to act as a current limiting impedance to compensate for the negative characteristics of the load.

The "constant current choke" is an element having an impedance component for limiting an input current from the power supply side.
Generally, an inductor element is used, but a resistor may be used. The constant current choke may be connected to the input side of the main switching means, and may be the input side of the full-wave rectifier circuit when a full-wave rectifier circuit is used.

The “DC power supply” is capable of dimming control by controlling the phase of an AC power supply line on the input side. Therefore, a phase control dimmer such as a triac can be connected to the AC power supply line on the input side.

When viewed from the power supply side to the load side in the combination with the phase control dimmer, a series circuit configuration of the constant current choke and the main switching means is provided, so that a current flows from the power supply side to the load side. In addition, the current can always flow without an idle period, and a malfunction such as the phase control dimmer being erroneously turned on / off does not occur. This allows
It is possible to provide a bulb-type fluorescent lamp capable of performing phase control for performing dimming similar to dimming lighting of a normal incandescent lamp without flickering of the fluorescent arc tube. In addition, even if the voltage obtained from the DC power supply is a pulsating voltage, the current flows without a pause, so that distortion of the input current is suppressed. For this reason, it is possible to cope with this by devising the connection without separately providing a special circuit element in the inverter circuit. As a result, it is possible to provide a configuration suitable for a compact fluorescent lamp with a small mounting space.

The invention described in claim 3 is the invention according to claim 1 or 2
In the light bulb-type fluorescent lamp according to any one of the above, the lighting circuit includes a detecting means for detecting the end of life of the fluorescent arc tube based on the terminal voltage of the smoothing capacitor.

The "detecting means" comprises a voltage detecting circuit for detecting the terminal voltage of the smoothing capacitor. At the end of the life of the fluorescent arc tube, it is in a half-wave discharge state, and the smoothing capacitor is in a state of only charging or discharging, and its terminal voltage is different from the voltage value at normal lighting before the end of the life. What is necessary is just a thing which can detect a difference. On the output side of the detection means, the oscillation operation of the inverter circuit is stopped based on the end-of-life detection output of the detection means,
Alternatively, a protection circuit for forcibly turning off the light is provided.

According to the present invention, the end of the life of the fluorescent tube can be easily and reliably detected simply by providing the detecting means for detecting the terminal voltage of the smoothing capacitor without providing the lamp voltage detecting means or the half-wave current detecting means. And take protective measures.

The invention described in claim 4 is the first to third aspects of the present invention.
In the light bulb-type fluorescent lamp according to any one of the above, the smoothing capacitor includes a circuit element which is connected in parallel to the fluorescent light emitting tube via the filament and which can conduct in a DC manner.

The term "circuit element capable of direct current conduction" means a circuit element through which a low-frequency current can flow. Generally, an inductor element is used, but a switch element or the like may be used. This circuit element forms a simple filament preheating circuit for the filament.

According to the present invention, it is possible to preheat the filament only by passing the charging current for the smoothing capacitor through the DC-conductive circuit element and the filament without providing a special control system for preheating the filament. Becomes As a result, it is possible to provide a configuration suitable for a bulb-type fluorescent lamp having a small mounting space with respect to filament preheating.

The fifth aspect of the present invention provides the first to fourth aspects.
In the bulb-type fluorescent lamp according to any one of the above, the inverter circuit includes a single-stone inverter circuit.

The invention according to claim 6 is the invention according to claims 1 to 4.
In the light bulb-type fluorescent lamp according to any one of the above, the inverter circuit comprises a half-bridge type inverter circuit.

In either case of the single-stone inverter circuit or the half-bridge inverter circuit,
The operation described in any one of (1) to (4) is obtained.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

<Structure> FIG. 1 is a front view of a bulb-type fluorescent lamp of the present embodiment, FIG. 2 is a horizontal sectional view thereof, and FIG. 3 is an exploded perspective view.

In these figures, 11 is an envelope, 12
Is a base, 13 is a partition, 14 is a fluorescent tube, and 15 is a lighting circuit.

The envelope 11 includes a light-transmitting globe 11a and a light-shielding base 11b as a base. This bulb-shaped fluorescent lamp has a height of about 110 to 125 m including the base 12.
m. Translucent glove 11a
Is made of glass having a maximum outer diameter of 60 mm, and has a bottomed cylindrical shape having a light diffusing film formed on the inner surface. Light-shielding substrate 1
1b has a cup shape made of a synthetic resin, a base 12 is attached to a base, and a translucent glove 11a is fixed to an open end. The translucent glove 11a is adhered to the open end of the light-shielding substrate 11b using a silicone adhesive. The partition 13 is formed by shaping a white synthetic resin.
The light-transmitting glove 11a is attached to the open end of the light-shielding substrate 11b.
Together with the silicone adhesive. In this way, the partition 13 divides the interior of the envelope 11 into the light emitting chamber A.
And a circuit storage room B. The partition 13 has a fluorescent tube support hole 13a.

The fluorescent tube 14 includes a bulb 14c, electrodes (not shown), a phosphor layer, and a discharge medium. The bulb 14c is formed, for example, in a shape in which three elongated glass tubes each having an outer diameter of 10 mm, a wall thickness of about 0.8 mm, and a length of 120 mm bent in a U-shape at the center are connected. The height of the fluorescent tube 14 is about 55 mm, and the discharge path length is about 250 mm. The electrodes of the fluorescent light emitting tube 14 are of a hot cathode type, and a pair of them is sealed at both ends of a bulb 14c. The phosphor layer is formed on the inner side of the bulb 14c. The discharge medium is 4 mercury and argon.
It is made of a rare gas of 00 Pa and is sealed in the valve 14c after exhausting the inside of the valve 14c.

The fluorescent light emitting tube 14 is inserted into the fluorescent light emitting tube support hole 13a of the partition 13 from the light emitting chamber A side and fixed to the partition 13 with a silicone adhesive to be supported. Eleven light emitting chambers A are arranged. An intermediate portion of the fluorescent light emitting tube 14 is filled with a silicone adhesive filled through a silicone adhesive filling hole (not shown) to form a partition wall 13.
It is stuck to.

The lighting circuit 15 includes an inverter circuit, which will be described later, for generating a high frequency for operating the fluorescent tube 14 and is mounted on a substrate 16. Circuit elements constituting the lighting circuit 15 are mounted on the front and back of the substrate 16. And are connected as appropriate. Here, the substrate 16 is formed as a circular substrate having a size corresponding to the inner diameter of the partition 13.

<Circuit Configuration> FIG. 4 is a schematic circuit diagram showing a lighting circuit 15 provided in the compact fluorescent lamp of the present embodiment.

The lighting circuit 15 of the present embodiment is mainly composed of a one-stone inverter circuit 21. In FIG. 4, 22 is a DC power supply, 23 is a main switching means, 2
4 is a drive circuit, 25 is a series circuit.

The DC power supply 22 includes, for example, a noise prevention capacitor C1 connected to the commercial 100V AC power supply 16,
The commercial AC power supply 1 is connected via the noise preventing capacitor C1.
6 is connected to a full-wave rectifier circuit REC. As a result, the pulsating DC voltage obtained by rectifying the commercial AC power supply 16 is supplied to the single-pole inverter circuit 21 from the output terminal. Commercial AC power supply 16 and capacitor C for noise prevention
A phase control dimmer 17 such as a triac is interposed on the AC input line between the first and second AC input lines.

A series circuit of the constant current choke L1 and the main switching means 23 is connected between the output terminals of the full-wave rectifier circuit REC. The main switching means 23 is composed of, for example, an enhancement type MOSFET, and a flyback diode D1 is connected in parallel.

The series circuit 25 connected in parallel to the main switching means 23 includes a ballast choke L2, a fluorescent light emitting tube 14, and a smoothing capacitor C2 composed of an electrolytic capacitor.
And are connected in series. A preheating capacitor C3 is connected between the filament electrodes 14a and 14b on both sides of the fluorescent tube 14. Further, there is provided a resonance capacitor C4 which is connected in parallel to the ballast choke L2 and the fluorescent light emitting tube 14 and forms an LC parallel resonance circuit with the ballast choke L2.

<Circuit Operation> First, as a basic operation, a charging current to the smoothing capacitor C2 is considered. Even when the power is turned on, the fluorescent tube 14 is interposed in the charging path from the DC power supply 22 to the smoothing capacitor C2, and the fluorescent tube 14 is not charged until the fluorescent tube 14 starts discharging. No charging current flows, and the fluorescent tube 14
After the start of the discharge, the inrush current to the smoothing capacitor C2 is reduced by the impedance component of the fluorescent tube 14. For this reason, the connection of the smoothing capacitor C
2 can be reduced. As a result, a smoothing capacitor C2 having a low withstand voltage can be used, and a circuit configuration suitable for a compact fluorescent lamp with a small mounting space can be obtained.

Next, the operation involved in turning on / off the main switching means 23 controlled by the drive circuit 24 will be described. When the main switching means 23 is turned on,
Current flows from the DC power supply 22 to the closed circuit to the constant current choke L1, the main switching means 23 and the DC power supply 22, and the charge stored in the smoothing capacitor C2 is charged by the fluorescent light emitting tube 14 and the preheating capacitor C3. Parallel circuit, ballast choke L2, main switching means 23
And a smoothing capacitor C2 discharges in a closed circuit. On the other hand, when the main switching means 23 is turned off, the energy stored in the ballast choke L2 is applied to the fluorescent tube 14 via the resonance capacitor C4, and the fluorescent light is emitted from the LC parallel resonance circuit formed by the ballast choke L2 and the resonance capacitor C4. Filament electrode 14 of tube 14
a, a preheating capacitor C3, a filament electrode 14b,
A load current flows to the resonance capacitor C4.

Such an operation is performed by the main switching means 23.
It repeats with turning on and off.

Here, when viewed from the power supply side to the load side in combination with the phase control dimmer 17, a series circuit configuration of the constant current choke L1 and the main switching means 23 is provided. Since the current can be always flowed without a pause in the current through the path for flowing the current, the phase control dimmer 17 is not erroneously turned on / off. Accordingly, it is possible to provide a bulb-type fluorescent lamp capable of performing phase control for performing dimming similar to dimming lighting of a normal incandescent lamp without flickering of the fluorescent arc tube 14. In addition, even if the voltage obtained from the DC power supply 22 is a pulsating voltage, the current flows without a pause, so that distortion of the input current is suppressed. For this reason, it is possible to cope with this by devising the connection without separately providing a special circuit element in the inverter circuit 21, and as a result, it is possible to provide a circuit configuration suitable for a compact fluorescent lamp with a small mounting space.

In the case of the configuration of the present embodiment, when the dimming is deepened by the phase control dimmer 17, the voltage Vc of the smoothing capacitor C2 is reduced, and when the lamp current has a pause, this smoothing is performed. The capacitor C2 for use is no longer charged, and is turned off naturally.

Next, a second embodiment of the present invention will be described with reference to FIG. The same portions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted (the same applies to the following embodiments).

FIG. 5 is a schematic circuit diagram showing a lighting circuit 15 provided in the compact fluorescent lamp of the present embodiment. In the present embodiment, the connection point of the resonance capacitor C4 is changed. In other words, the resonance capacitor C4 is connected in parallel to the main switching means 23, so that the ballast choke L2 and the fluorescent tube 14 are connected in parallel. The operation is similar to that of FIG.

A third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic circuit diagram showing a lighting circuit 15 provided in the compact fluorescent lamp of the present embodiment.

In this embodiment, the connection point is changed so that the constant current choke L1 is connected to the other output terminal side of the full-wave rectifier circuit REC in the DC power supply 22. The operation is similar to that of FIG.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a schematic circuit diagram showing a lighting circuit 15 provided in the compact fluorescent lamp of the present embodiment.

In the present embodiment, the connection point is changed so that the constant current choke L1 is connected to the input side of the full-wave rectifier circuit REC in the DC power supply 22. The operation is similar to that of FIG.

A fifth embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a schematic circuit diagram showing a lighting circuit 15 included in the bulb-type fluorescent lamp of the present embodiment, and FIG. 9 is a partial circuit diagram schematically showing a state at the end of life.

In this embodiment, the smoothing capacitor C2
End detecting circuit 2 as detecting means for detecting the terminal voltage of
6 and a protection circuit 27 that operates based on the end-of-life detection output of the end-of-life detection circuit 26.

Considering the state at the end of the life of the fluorescent tube 14, a half-wave discharge state occurs. If the direction of the half-wave is, for example, the direction shown in FIG. 9A, only the current in the charging direction flows through the smoothing capacitor C2 and does not discharge, so that the charge tends to rise immediately. On the other hand, if the direction of the half-wave is, for example, the direction shown in FIG. 9B, the current in the charging direction does not flow through the smoothing capacitor C2, and only the discharge occurs, so that the charge tends to decrease immediately. . In addition, when there is no point in which the fluorescent light emitting tube 14 does not light up at all, the terminal voltage of the smoothing capacitor C2 becomes 0V.

In any case, at the end of the life, the terminal voltage of the smoothing capacitor C2 is different from the voltage at the time of normal lighting before the end of the life.
By performing the detection in step 6, it can be determined whether or not the fluorescent arc tube 14 has reached the end of its life. This end-of-life detection circuit 26
When it is detected that the end of life has been reached, the protection circuit 27 performs a protection operation such as stopping the oscillation operation of the inverter circuit 21 or forcibly turning off the light.

As described above, in this embodiment, the end-of-life detecting circuit 26 for simply detecting the terminal voltage of the smoothing capacitor C2 is provided without providing any special lamp voltage detecting means or half-wave current detecting means. Thus, the end of life of the fluorescent light emitting tube 14 can be easily and reliably detected, and protective measures can be taken.

A sixth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a schematic circuit diagram showing a lighting circuit 15 provided in the compact fluorescent lamp of the present embodiment.

In this embodiment, the fluorescent light emitting tube 14
An inductor element 28 is connected in parallel between the filament electrodes 14a and 14b. This inductor element 28
Is a circuit element that can be conducted in a DC manner with respect to the smoothing capacitor C2.
8) forms a simple filament preheating circuit for the filaments 14a and 14b.

According to the present embodiment, the filament 14
The filament preheating can be performed only by flowing the charging current for the smoothing capacitor C2 through the DC-conductive inductor element 28 and the filaments 14a and 14b without providing a special control system for preheating the filaments a and 14b. Becomes As a result, it is possible to provide a circuit configuration suitable for a bulb-type fluorescent lamp having a small mounting space with respect to filament preheating.

A seventh embodiment of the present invention will be described with reference to FIG. FIG. 11 is a schematic circuit diagram showing a lighting circuit 15 provided in the compact fluorescent lamp of the present embodiment.

In this embodiment, a half-bridge type inverter circuit 33 including a pair of switching means 31 and 32 is used.
An example of application to the lighting circuit 15 including the following is shown. After the switching units 31 and 32, the switching unit 32 is the main switching unit. The operation is similar to that of FIG.

[0071]

According to the bulb-type fluorescent lamp of the first aspect of the present invention, the lighting circuit mounted on the substrate attached to the base has a fluorescent arc tube in the charging path from the DC power supply to the smoothing capacitor. The charging current to the smoothing capacitor does not flow until the fluorescent luminous tube starts discharging, and the inrush current can be reduced by the impedance component of the fluorescent luminous tube even after the discharge starts,
For this reason, the rush current can be reduced by improving the connection without particularly providing an impedance element separately, so that a smoothing capacitor having a low withstand voltage can be used, and a compact fluorescent lamp with a small mounting space can be used. The circuit configuration suitable for the above can be provided.

According to the bulb-type fluorescent lamp of the second aspect of the present invention, when viewed from the power supply side to the load side in a combination with the phase control dimmer, a series circuit configuration of the constant current choke and the main switching means. Therefore, the current can flow from the power supply side to the load side without any pauses, so that the phase control dimmer may be turned on and off by mistake. Accordingly, it is possible to provide a bulb-type fluorescent lamp capable of performing phase control for performing dimming similar to dimming lighting of a normal incandescent lamp without flickering of the fluorescent arc tube. In addition, even if the voltage obtained from the DC power supply is a pulsating voltage, the current flows without a pause, so that distortion of the input current can be suppressed. For this reason, a special circuit element is used in the inverter circuit. Can be dealt with by devising the connection without separately providing a circuit configuration suitable for a compact fluorescent lamp with a small mounting space.

According to the bulb-type fluorescent lamp of the third aspect of the present invention, it is simple and simple to provide the detecting means for detecting the terminal voltage of the smoothing capacitor without providing the lamp voltage detecting means or the half-wave current detecting means. The end of life of the fluorescent tube can be reliably detected, and protective measures can be taken.

According to the fourth aspect of the invention, there is provided a circuit element and a filament capable of conducting a charging current to a smoothing capacitor in a DC manner without providing a special control system for preheating the filament. Thus, it is possible to preheat the filament simply by flowing the electric current through the wire, and as a result, it is possible to provide a circuit configuration suitable for a bulb-type fluorescent lamp having a small mounting space with respect to the preheating of the filament.

According to the bulb-type fluorescent lamp of the invention described in claim 5 or 6, in either case of the single-stone inverter circuit or the half-bridge type inverter circuit, the lamp according to any one of claims 1 to 4 The described effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a compact fluorescent lamp according to a first embodiment of the present invention.

FIG. 2 is a horizontal sectional view thereof.

FIG. 3 is an exploded perspective view thereof.

FIG. 4 is a schematic circuit diagram showing a lighting circuit included in the compact fluorescent lamp of the present embodiment.

FIG. 5 is a schematic circuit diagram showing a lighting circuit included in a compact fluorescent lamp according to a second embodiment of the present invention.

FIG. 6 is a schematic circuit diagram showing a lighting circuit included in a compact fluorescent lamp according to a third embodiment of the present invention.

FIG. 7 is a schematic circuit diagram showing a lighting circuit included in a compact fluorescent lamp according to a fourth embodiment of the present invention.

FIG. 8 is a schematic circuit diagram showing a lighting circuit provided in a compact fluorescent lamp according to a fifth embodiment of the present invention.

FIG. 9 is a partial circuit diagram schematically showing a state at the end of life.

FIG. 10 is a schematic circuit diagram showing a lighting circuit included in a compact fluorescent lamp according to a sixth embodiment of the present invention.

FIG. 11 is a schematic circuit diagram showing a lighting circuit included in a compact fluorescent lamp according to a seventh embodiment of the present invention.

[Explanation of symbols]

 12: Base 14: Fluorescent tube 15: Lighting circuit 21: 1 stone inverter circuit 22: DC power supply 23: Main switching means 25: Series circuit 26: Detection means 32: Main switching means 33: Half bridge type inverter circuit

Claims (6)

[Claims] 1. A base having a base; a fluorescent tube mounted on the base; a substrate mounted in the base; a fluorescent tube interposed in a closed loop between a DC power supply and a smoothing capacitor. A lighting circuit mounted on a substrate including an inverter circuit for generating a high frequency to be operated; 2. An inverter circuit, comprising: a DC power supply controlled for dimming by phase control; main switching means connected between output terminals of the DC power supply; and a ballast choke connected in parallel to the main switching means. A series circuit of a fluorescent tube and a smoothing capacitor; a resonant capacitor connected in parallel to the ballast choke and the fluorescent tube to resonate with the ballast choke; and an input current connected to the input side of the main switching means. And a constant current choke for limiting the electric current. 3. The bulb-type fluorescent lamp according to claim 1, wherein the lighting circuit includes a detecting means for detecting an end of life of the fluorescent arc tube based on a terminal voltage of the smoothing capacitor. 4. The bulb-type fluorescent lamp according to claim 1, further comprising a circuit element which is connected in parallel to the fluorescent luminous tube via a filament and has a circuit element capable of direct current conduction in the smoothing capacitor. . 5. The bulb-type fluorescent lamp according to claim 1, wherein the inverter circuit comprises a single-stone inverter circuit. 6. The bulb-type fluorescent lamp according to claim 1, wherein the inverter circuit comprises a half-bridge type inverter circuit.