JPH11162671A - Discharge lamp lighting device and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold in safe condition a discharge lamp in the final period of its lifetime by equipment the discharge lamp with a parallel circuit consisting of a posistor whose resistance increases enlarges with the rising temp. in the neighborhood of the tube end of an arc tube bulb and a current fuse to blow when a current exceeds the specified current. SOLUTION: The power from a commercial AC source 1 is fed to a rectifier 2 and converted into DC power, which is fed to an LC resonator circuit 3b of a discharge lamp 4 through a power factor improving LC circuit 3a of an inverter circuit 3, and upon inversion into a high frequency AC power, the discharge lamp 4 is lighted therewith in high frequency. The discharge lamp 4 is furnished on its electrode side with a parallel circuit consisting of a posistor 4f whose resistance increases with the rising temp. in the neighborhood of the end of an arc tube bulb and a current fuse 4a to blow when a current exceeding the specified current. If a detecting part 5 detects that the lamp is at the final stage of its lifetime, a safety measure is actuated with shuts off the high frequency power supplied from the inverter circuit 3 to the filament 4d of the discharge lamp 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp lighting device and an illuminating device having an inverter circuit.

[0002]

2. Description of the Related Art For example, a fluorescent lamp, which is a discharge lamp, is formed by forming a phosphor film on the inner surface of an arc tube and closing the tube end of the arc tube with a sealing member. A pair of internal leads are hermetically pierced through the sealing member, and a filament coil is wound around the inner ends of these internal leads to form a filament circuit. In a compact fluorescent lamp, the arc tube bulb is formed in a U-shape or the like to achieve miniaturization.

On the other hand, an electron emitting material is applied to the filament, and when a current is applied to an electrode (cathode) to preheat the filament, thermoelectrons are emitted from the filament, and the thermoelectrons are emitted to the opposite electrode (anode). It is pulled and moved to start discharge. Thereby, the fluorescent lamp is turned on.

Here, the fluorescent lamp (discharge lamp) is lit by a discharge lamp lighting device. In the case of a high-frequency lighting system, an alternating current of a commercial frequency (50 Hz or 60 Hz) is rectified by a rectifying unit, and the direct current is once converted. Then, the fluorescent lamp is further converted to high frequency (for example, 20 kHz to 100 kHz) alternating current by an inverter circuit, and the fluorescent lamp is lit at high frequency.

[0005]

However, at the end of the life of the fluorescent lamp, the filament portion of the fluorescent lamp is overheated, and the tube end of the arc tube bulb generates heat. If left as it is, melting of the socket portion and valve cracking may occur.

That is, when the fluorescent lamp is turned on or off for a long period of time, filament constituent materials such as tungsten and an electron emitting material used as the material of the filament are scattered and adhere to and deposit on the tip end surface of the sealing member close to the filament. When the filament is broken, an electric current flows through the scattered and deposited conductor to generate heat. Also, if the lighting is maintained or blinked in the state of the end of life and the electron emitting substance applied to the filament is scattered, the filament part of the fluorescent lamp is overheated by this heat generation,
Heat is generated at the tube end of the arc tube bulb, causing melting of the socket and cracking of the bulb.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a discharge lamp lighting device and a lighting device capable of performing a safe operation when an abnormal state occurs at the end of lamp life of a discharge lamp.

[0008]

According to a first aspect of the present invention, there is provided a discharge lamp lighting device including a posistor having a resistance value which increases with a rise in temperature in the vicinity of a tube end of an arc tube. A discharge lamp having a parallel circuit with a current fuse that operates when the rectifier section converts a commercial AC voltage into a DC voltage; and And an inverter circuit for converting the AC power into an AC power supply and lighting the discharge lamp at a high frequency.

[0009] The vicinity of the tube end of the arc tube bulb is around the tip of a sealing member for closing the tube end of the arc tube bulb, and a filament is located at the tube end in the arc tube bulb. I have. The posistor connected in parallel with the current fuse is
The arc tube is provided near the end of the bulb so as to be sensitive to the ambient temperature of the tip of the sealing member. The resistance value of the posistor increases as the temperature rises, and more current flows through the current fuse connected in parallel.

Therefore, the temperature at which the current flows through the conductor scattered and adhered to the distal end surface of the sealing member of the arc tube bulb and the temperature at which heat is generated, and the heat generated by the filament when the lighting is maintained when the electron emitting material is exhausted, cause As the resistance value increases, more current flows through the current fuse and the current fuse is quickly activated.

When the current fuse is activated, the current supply path to the filament is cut off, so that no heat is generated at the tip of the arc tube bulb, and the discharge lamp is maintained in a safe state.

Commercial AC power supply is 50Hz or 60Hz
The frequency for lighting the discharge lamp at a high frequency in the inverter circuit is preferably 20 kHz to 100 kHz.

According to the discharge lamp lighting device of the first aspect, the end of the lamp life is detected by a parallel circuit of a posistor and a current fuse provided in the discharge lamp. When the end of the lamp life is detected, the current fuse is opened and the filament circuit is opened, so that the discharge lamp is maintained in a safe state.

A discharge lamp lighting device according to a second aspect of the present invention is characterized in that a capacitor constituting an LC resonance circuit in an inverter circuit is disposed near a tube end of an arc tube bulb.

Since the capacitor is generally a component that is liable to be thermally damaged, when the temperature near the tube end of the arc tube bulb becomes excessive, it is destroyed by the heat. Since the LC resonance circuit becomes inactive due to the destruction of the capacitor, the discharge lamp is maintained in a safe state. The resonance capacitor may also serve as a preheating capacitor for forming a closed circuit when the discharge lamp is preheated.

In the discharge lamp lighting device according to the second aspect of the present invention, when the temperature near the tube end of the arc tube bulb becomes excessively high, either the current fuse or the capacitor constituting the LC resonance circuit is used. , The filament circuit can be interrupted, so that the discharge lamp can be maintained in a safe state by achieving dualization.

According to a third aspect of the present invention, there is provided an illuminating device including the discharge lamp lighting device according to the first or second aspect; and a fixture main body on which the discharge lamp lighting device is mounted.

The rectifier and the inverter circuit constituting the discharge lamp lighting device are housed inside the fixture body, and the discharge lamp is mounted outside to form a lighting device.

According to the third aspect of the present invention, since the end of the lamp life is properly detected, a safe lighting device can be provided without exposing the discharge lamp to an abnormal state.

[0020]

Embodiments of the present invention will be described below. FIG. 1 is a circuit configuration diagram of a discharge lamp lighting device according to an embodiment of the present invention.

In FIG. 1, the frequency is 50 Hz or 6 Hz.
The 0 Hz commercial AC power supply 1 is input to the rectifier 2 of the discharge lamp lighting device, and is converted into DC by the rectifier 2. Rectifier 2
Comprises a full-wave rectifier 2a and a smoothing capacitor 2b.

The DC power obtained by the rectifier 2 is input to the inverter circuit 3 and converted into a high-frequency AC power of 20 kHz to 100 kHz to turn on the discharge lamp 4 at a high frequency. The DC power obtained by the rectifier 2 is supplied to the LC resonance circuit 3b of the discharge lamp 4 via the power factor improving LC circuit 3a of the inverter circuit 3.
And the output of the inverter circuit 3 is controlled by the control means 3c.

On the power supply side of the discharge lamp 4, a parallel circuit of a current fuse 4a and a posistor 4f is provided.
Is connected to the filament 4d. The LC resonance circuit 3b includes a coil L1 and a capacitor C1. The capacitor C1 is used for preheating the filament 4d when the discharge lamp 4 is turned on, and is used for resonance for high frequency lighting after the discharge lamp 4 is turned on.

The posistor 4f connected in parallel with the current fuse 4a detects the end of lamp life based on the temperature near the tube end of the arc tube. That is, the resistance value of the posistor 4f increases as the temperature increases, and the current flowing through the current fuse 4a connected in parallel increases. That is, when the temperature in the vicinity of the tube end of the arc tube rises, it acts to promote the operation of the current fuse 4a. Then, when the temperature near the tube end of the arc tube reaches a predetermined set temperature, the current fuse 4a operates to open the filament circuit. As a result, the end of the lamp life is detected, and a safe operation of shutting off the supply of high frequency power from the inverter circuit 3 to the filament 4d of the discharge lamp 4 is performed.

On the other hand, a detector 5 for detecting the end of lamp life by half-wave discharge of the discharge lamp 4 is provided as required. When the end of the lamp life is detected, the detection unit 5 performs a safety operation of reducing or stopping the output of the inverter circuit 3.

At the end of lamp life, filament 4d
The electron-emitting substance applied to the substrate is scattered and reduced, and the discharge lamp 4 causes a half-wave discharge. Therefore, in the detection unit 5 of the discharge lamp lighting device, the half-wave discharge is detected by the half-wave discharge detection unit 5a, and the determination unit 5b determines whether or not the generation level of the half-wave discharge exceeds a predetermined value. When it is determined that the lamp is at the end of its life, the control unit 3c of the inverter circuit 3 is notified of the fact. In that case, the control means 3c performs a safety operation of reducing or stopping the output of the inverter circuit 3.

Note that the start-time operation inhibiting section 5c operates during a period of from ten seconds to several tens of seconds after the start of the discharge lamp lighting device.
This locks the detection operation at the end of lamp life of the determination unit 5b. By the operation of the startup operation prevention unit 5c, it is possible to prevent the detection unit 5 from malfunctioning in a transient state at the time of startup of the discharge lamp lighting device. I have. It should be noted that the detection unit 5 is provided as needed, and is not necessarily provided.

FIG. 2 is an explanatory view showing an example of the discharge lamp 4 used in the embodiment of the present invention. The discharge lamp 4 shown in FIG. 2 is a compact fluorescent lamp in which the arc tube 4b is formed in a U-shape to reduce the size.
c. That is, the posistor 4f
Detects the temperature near the tube end of the arc tube 4b inside the socket portion 4c and increases the resistance value according to the detected temperature. The temperature near the filament 4d inside the arc tube 4b indicates the lamp life. When the temperature indicating the last stage is reached, the posistor 4f is set so that a current for operating the current fuse flows through the current fuse 4a.

The reason why the end of the lamp life can be determined from the temperature near the filament 4d in the arc tube bulb 4b is as follows. In the vicinity of the filament 4d in the arc tube 4b, that is, in the tip end portion of the sealing member 4e for closing the tube end of the arc tube 4b, the scattered conductor is deposited. The end of lamp life can be determined by the amount of the conductor. Electric current flows through the deposited conductors and generates heat,
The calorific value is shown as a function of the amount of conductor. Thus, the end of the lamp life can be detected by detecting the temperature near the tube end of the arc tube bulb 4b.

Therefore, the posistor 4f is connected to the sealing member 4f.
A current flows through the conductor scattered and attached to the front end surface of e, and the resistance value is changed in response to the temperature at which heat is generated. Due to this change in the resistance value, the current fuse 4a operates, and the current fuse 4a
By the operation of a, the filament circuit for supplying power to the filament 4d is cut off, and the discharge lamp 4 is kept in a safe state. Thus, the detection sensitivity at the end of the lamp life is determined by the characteristics of the host 4f and the setting of the sensitive current level of the current fuse 4a.

FIG. 3 is an explanatory view showing another example of the discharge lamp 4 used in the embodiment of the present invention. This discharge lamp 4
Is different from the discharge lamp 4 shown in FIG. 2 in that the capacitor C1 constituting the LC resonance circuit 3b in the inverter circuit 3 is
It is arranged near the tube end of the arc tube bulb 4b.

LC resonance circuit 3 in inverter circuit 3
The capacitor C1 constituting b is a resonance capacitor for high-frequency lighting, and is also a preheating capacitor for preheating the filament 4d when the discharge lamp 4 is turned on.

When the discharge lamp 4 is turned on, it is used as a preheating capacitor for preheating the filament 4d. When the filament 4d is preheated and discharge starts between the filaments 4d, a resonance circuit for high frequency lighting is connected to the coil L1.
Form with.

The capacitor C1 of the LC resonance circuit 3b is installed near the end of the arc tube bulb 4d. Accordingly, when the temperature near the tube end of the arc tube bulb 4d becomes excessively high, the capacitor C1 is destroyed by the heat.
The filament circuit is cut off by the destruction of the capacitor C1, and the discharge lamp 4 is maintained in a safe state.

Therefore, even if the temperature near the tube end of the arc tube bulb 4d becomes excessively high and the filament circuit cannot be cut off by the current fuse, the filament circuit can be cut off by the capacitor C1 of the LC resonance circuit 3b. The electric lamp 4 can be held more safely.

The discharge lamp lighting device configured as described above is mounted on the fixture main body 6 to form a lighting device as shown in FIG. That is, the rectifying unit 2 and the inverter circuit 3 constituting the discharge lamp lighting device are housed inside the fixture main body 6, and the discharge lamp 4 is mounted outside the fixture main body 6 to form a lighting device. According to this lighting device, the end of the lamp life can be detected more accurately, so that the discharge lamp 4 can be used safely without exposing the discharge lamp 4 to an abnormal state.

[0037]

As described above, according to the first aspect of the present invention, the end of the lamp life is detected by the parallel circuit of the posistor and the current fuse provided in the discharge lamp, and the end of the lamp life is detected. Then, the current fuse is opened and the filament circuit is opened, so that the discharge lamp is kept in a safe state. Therefore, melting of the socket and cracking of the valve can be prevented.

According to the second aspect of the invention, even when the temperature near the tube end of the arc tube bulb becomes excessively high and the current fuse does not operate, the filament circuit is cut off by the capacitor constituting the LC resonance circuit. Therefore, the reliability of maintaining the discharge lamp in a safe state is improved.

According to the third aspect of the present invention, since the end of the lamp life can be accurately detected, it is possible to obtain a lighting device that does not expose the discharge lamp to an abnormal state.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a discharge lamp lighting device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a discharge lamp used in the embodiment of the present invention.

FIG. 3 is an explanatory view showing another example of the discharge lamp used in the embodiment of the present invention.

FIG. 4 is a perspective view of a lighting device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 Rectifier 3 Inverter circuit 3b LC resonance circuit 4 Discharge lamp 4a Current fuse 4b Arc tube bulb 4d Filament 4f Posister 5 Detector 6 Instrument body

Claims (3)

[Claims] 1. A discharge lamp having a parallel circuit of a posistor whose resistance value increases in accordance with a temperature rise near a tube end of an arc tube bulb and a current fuse which operates when a current of a predetermined current value or more flows. A rectifier for converting a commercial AC voltage to a DC voltage; and an inverter circuit having an LC resonance circuit, for converting the DC voltage obtained by the rectifier to a high-frequency AC voltage and lighting the discharge lamp at a high frequency. A discharge lamp lighting device comprising: 2. The discharge lamp lighting device according to claim 1, wherein a capacitor constituting an LC resonance circuit in the inverter circuit is disposed near a tube end of the arc tube bulb. 3. A lighting device comprising: the discharge lamp lighting device according to claim 1; and a fixture main body to which the discharge lamp lighting device is mounted.