JPH08273593A - Fluorescent lamp and luminaire - Google Patents

Abstract

PURPOSE: To extend the life of a fluorescent lamp by enhancing its starting property. CONSTITUTION: Three weld wires 5a, 5b, 5c and a support wire 5d are supported against a stem 4 which seals each end of a glass bulb 2 having a thin phosphor film formed on its inner surface and a rare gas sealed therein. An emitter composed chiefly of an oxide of an alkali metal is applied to a small coil to form a filament 6a of small heat capacity. An emitter composed chiefly of a metal oxide having a greater work function than the alkali metal oxide is applied to a large coil in large amounts to form a filament 6b of large heat capacity. One end of each filament 6a, 6b is connected to the weld wire 5a, the other end of the filament 6a of small heat capacity is connected to the weld wire 5b, and the other end of the filament 6b of large heat capacity to the weld wire 5c. The support wire 5d is provided with a bimetal 7 which makes contact with the weld wire 5b at room temperature and with the weld wire 5c at a predetermined temperature. Therefore, a current is passed through the filament 6a of small heat capacity to start the fluorescent lamp at elevated temperature in a short time, and after being turned on the lamp can be turned on by use of the filament 6b of large heat capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp having a hot cathode and a lighting fixture equipped with this fluorescent lamp.

[0002]

2. Description of the Related Art Generally, in order to prolong the life of a filament of a fluorescent lamp, the absolute amount of an emitter coated on the surface of a coil forming the filament is increased, and the atomic weight of a sealed gas serving as a discharge medium is increased. thing,
Methods such as increasing the pressure of the gas to be enclosed are adopted.

That is, the method of increasing the absolute amount of the emitter is intended to prolong the life of the filament by increasing the absolute amount of the consumed emitter without changing the consumption rate of the emitter consumed by the discharge. In addition, the method of increasing the atomic weight of the enclosed gas and the method of increasing the enclosed gas pressure are intended to suppress the diffusion loss of the emitter released from the filament, that is, to suppress the consumption rate of the emitter to prolong the life of the filament.

However, in the method of increasing the atomic weight of the filling gas, for example, krypton (K) is used as the filling gas.
Although r) and xenon (Xe) are used, these gases require a high starting voltage because they do not cause the Penning effect with mercury (Hg) as a discharge medium. Further, since the diffusion loss in the positive column is reduced and the electron temperature is lowered, the luminous efficiency of the fluorescent lamp is deteriorated. In addition, the method of increasing the pressure of the enclosed gas also requires a high starting voltage and causes a decrease in luminous efficiency. On the other hand, the method of increasing the absolute amount of the emitter does not increase the starting voltage or decrease the luminous efficiency,
Increasing the absolute amount of the emitter increases the heat capacity of the filament and delays the temperature rise of the filament at the time of starting the fluorescent lamp. For this reason, there are problems that it takes a long time to start the fluorescent lamp, and the filament is started before reaching the arc transition temperature to cause blackening of the tube wall of the fluorescent lamp at an early stage. Especially recently
The preheating condition at the time of starting the fluorescent lamp for high frequency lighting is IEC
It is difficult to achieve long life while meeting this international standard.

Therefore, in order to easily start at a low voltage, a fluorescent lamp disclosed in, for example, JP-A-55-144652 is conventionally known.

The fluorescent lamp described in JP-A-55-144652 is for cold starting at both ends of the lamp tube and at a position where the filaments have a mutual distance smaller than the mutual distance between the filaments. A preheating filament is provided. Then, the fluorescent lamp is started and lit by the preheating filament, the mercury vapor pressure of the enclosed gas rises due to the heating by the discharge, and after this temperature rise, the preheating filament is switched to the filament by the interlock switch and the lighting is maintained by the filament.

[0007]

However, in the conventional fluorescent lamp described in Japanese Patent Laid-Open No. 55-144652, the preheating filaments to be turned on at the time of start-up are located at positions where the mutual distance is smaller than the mutual distance between the filaments. Since it is provided, both ends of the lamp tube are darker than these preheating filaments. For this reason, if the distance between the preheating filaments is shortened to start at a low temperature, the darkened portions at both ends of the lamp tube become wide, and there is a problem that uniform lighting is not possible.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a long-life fluorescent lamp and a lighting fixture which are excellent in startability.

[0009]

According to a first aspect of the present invention, there is provided a fluorescent lamp having a pair of input terminals, two filaments having different heat capacities, at least one of the pair of input terminals, and at least one of the two filaments. A hot cathode that is provided between the two, and that has a heat sensitive element that connects a filament having a small heat capacity to an input terminal at the time of starting, and connects a filament having a large heat capacity to the input terminal due to the heat generated by lighting; And an airtight container having a phosphor layer formed on the inner surface side thereof.

A fluorescent lamp according to a second aspect is provided between a pair of input terminals, two filaments having different heat capacities, at least one of the pair of input terminals, and at least one of the two filaments. The switching element that connects either one of the two filaments to the input terminal and the filament having a small heat capacity is connected to the input terminal by the switching element at the time of starting, and the switching element becomes the switching element after a predetermined time has elapsed after lighting. A hot cathode having a time constant circuit for switching and connecting a filament having a large heat capacity to an input terminal; and an airtight container having a phosphor layer formed on the inner surface to form a discharge path by providing the hot cathode at both ends; It is equipped with.

According to a third aspect of the present invention, in the fluorescent lamp according to the first or second aspect, the filament having a small heat capacity is coated with an emitter mainly composed of an oxide of an alkali metal.

A lighting fixture according to a fourth aspect comprises the fluorescent lamp according to any one of the first to third aspects, and a fixture main body on which the fluorescent lamp is mounted.

According to a fifth aspect of the present invention, in the light source according to the fourth aspect, the fluorescent lamp is turned on at a high frequency.

A lighting fixture according to a sixth aspect is the lighting fixture according to the fourth or fifth aspect, further comprising a high frequency lighting circuit for lighting the fluorescent lamp at a high frequency.

[0015]

In the fluorescent lamp according to the present invention, the filament having a small heat capacity connected to the input terminal via the heat-sensitive element is started and lit, and the filament having the large heat-sensitive element is connected to the input terminal by the heat generated after lighting. Since the connection is switched, the filament is fast-started and is lit with a small heat capacity filament, and after lit, the filament is maintained with a long heat capacity and a large heat capacity, so that the startability is excellent and the life can be extended.

In the fluorescent lamp according to the present invention, the filament having a small heat capacity is connected to the input terminal by the switching element at the time of starting, and the filament having a large heat capacity is inputted by the switching element after the elapse of a predetermined time by the time constant circuit. Since it is switched and connected to the terminals, the filament is fast-started and is lit with a small heat capacity filament, and after lit, the filament is maintained with a long life and a large heat capacity, so that the startability is excellent and the life is extended.

According to a third aspect of the present invention, in the fluorescent lamp according to the first or second aspect, the filament having a low heat capacity is formed by applying an emitter mainly composed of an oxide of an alkali metal having a low work function to the filament. For,
The temperature can be raised in a short time, and the startability is improved.

In the luminaire according to the fourth aspect, since the fluorescent lamp according to any one of the first to third aspects is mounted on the main body of the luminaire, the frequency of exchanging the fluorescent lamp having excellent startability is reduced and the operability is improved.

According to a fifth aspect of the present invention, in the light source according to the fourth aspect, since the fluorescent lamp is lit at a high frequency, the life of the fluorescent lamp for high frequency lighting whose preheating condition conforms to international standards is extended.

According to a sixth aspect of the present invention, in the light source according to the fourth or fifth aspect, since the fluorescent lamp is lit at a high frequency by the high frequency lighting circuit, the preheating condition complies with international standards and has a long life. High frequency lighting is possible easily.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of one embodiment of the fluorescent lamp of the present invention will be described below with reference to the drawings.

Note that FIG. 1 is a side view showing an embodiment of the fluorescent lamp of the present invention with a part cut away in the vicinity of one end.
Further, FIG. 2 is a side view showing a fluorescent lamp with one end and its vicinity being cut away. Further, FIG. 3 is an axial sectional view showing the fluorescent lamp. FIG. 4 is an explanatory diagram showing a connection state between a filament of a fluorescent lamp and a bimetal functioning as a heat sensitive element.

In FIGS. 1 to 4, reference numeral 1 is a fluorescent lamp, and this fluorescent lamp 1 has an elongated glass tube 2 which is a light-transmissive elongated tubular airtight container. A rare gas (not shown) serving as a discharge medium such as Ar) or mercury (Hg) is filled. As the rare gas, for example, 2.5 Torr of Ar and an appropriate amount of Hg are enclosed, and neon (Ne), krypton (Kr), xenon (Xe), or the like may be appropriately mixed.

On the inner surface of the glass tube 2, a phosphor layer (not shown) is formed as a thin film. As the phosphor layer, all kinds of phosphor layers such as a three-wavelength type phosphor and a continuous wavelength emission type halophosphate phosphor can be used.

Further, a pair of electrodes 3, 3 serving as discharge means for generating positive column discharge are provided at both ends of the glass tube 2, and these electrodes 3, 3 are provided at both ends of the glass tube 2. Are installed on the stems 4 and 4 for sealing. Then, the electrode 3 has three wells 5 supported by the stem 4.
a, 5b, 5c and supporting wire 5d, and wells 5a, 5b, 5c
It is composed of two filaments 6a and 6b whose ends are connected to each other.

The two filaments 6a and 6b have different heat capacities, and the filament 6a having a small heat capacity is, for example, cesium oxide (Cs ₂ O) on the outer peripheral surface of a small triple coil (not shown) made of tungsten and having a weight of 12 mg. Is formed by applying an unillustrated emitter whose main component is an alkali metal oxide and has a weight of 3.5 mg. on the other hand,
The filament 6b having a large heat capacity has a weight of, for example, 25 mg.
On the outer surface of a large-sized triple coil made of tungsten (not shown), a solid solution ((Ba, Sr, Ca) O) of a metal oxide such as barium oxide, strontium oxide, or calcium oxide having a work function larger than that of an oxide of an alkali metal. (Not shown) whose main component is not shown is applied by a weight of 7.2 mg, which is larger than the emitter amount of the filament 6a having a small heat capacity. Two filaments 6a and 6b
The same metal oxide, for example, (Ba, Sr, Ca) O, is applied to the filaments in different amounts to form a filament.
It is also possible to make a difference in the heat capacities of 6a and 6b.

Further, one of the wells 5a, 5b, 5c has one end from the end of the stem 4 to the glass tube 2
The outer lead 5a1 is formed so as to project along the tube axis direction of the inner lead 5a2 and the other end is located inside the glass tube 2.
And is formed on the stem 4. The ends of the inner leads 5a2 of the wells 5a are electrically and mechanically connected to the ends of the two filaments 6a and 6b, respectively, as shown in FIGS. On the other hand, two of the wells 5a, 5b, 5c are wells 5b, 5c.
Has one end embedded in the stem 4 and the other end located inside the glass tube 2 to form inner leads 5b1 and 5c1. Then, as shown in FIGS. 3 and 4, the tip ends of the inner leads 5b1 and 5c1 of the two wells 5b and 5c respectively have the other end portions of the filament 6a having a small heat capacity and the filament 6b having a large heat capacity. Is electrically and mechanically connected to.

On the other hand, one end of the support wire 5d projects from the end of the stem 4 along the tube axis direction of the glass tube 2 to form an outer lead 5d1, and the other end is located inside the glass tube 2 and is an inner lead. 5d2 is formed on the stem 4. An elongated strip-shaped bimetal 7, which is a heat-sensitive element, is provided at the tip of the inner lead 5d2 of the support wire 5d. Further, as shown in FIGS. 3 and 4, the bimetal 7 has one end in the longitudinal direction contacting the wells 5b to which the filament 6a having a small heat capacity is connected at normal temperature and when a predetermined heat is applied. The other end in the longitudinal direction is electrically and mechanically connected to the supporting wire 5d so that the well 5c to which the filament 6b having a large heat capacity is connected and has a switching function.

Further, at both ends of the glass tube 2, there are provided caps 9 for covering both ends of the glass tube 2. Further, on the end surface of the base 9, there are provided lamp pins 10 as two input terminals protruding along the tube axis direction of the glass tube 2. And, these lamp pins 10 and 10,
The outer lead 5a1 of the wells 5a and the outer lead 5d1 of the support wire 5d are separately electrically and mechanically connected.

In the fluorescent lamp 1, the lamp pins 10 and 10 of the base 9 are connected to the opposing lamp sockets of the main body of the apparatus having a high-frequency lighting circuit (not shown), and the fluorescent lamps 1 are mounted between the lamp sockets to be lit at a high frequency.

Next, the operation of the above embodiment will be described.

A high-frequency AC power supply is applied between the lamp pins 10 of the fluorescent lamp 1 mounted on the fixture body (not shown). One electrode 3 on the side to which this high-frequency AC power is applied
Serves as a cathode, and the other electrode 3 serves as an anode. The pair of electrodes 3 and 3 are in contact with the wells 5b to which the bimetal 7 connects the filament 6a having a small heat capacity. Therefore, the high frequency AC power source is applied to the filament 6a having a small heat capacity through the bimetal 7 of the electrode 3 serving as the cathode.

As a result, since the filament 6a has a small heat capacity, the filament 6a immediately rises in temperature and reaches the arc transition temperature in a short time of 0.5 to 1.0 second. Furthermore, since the filament 6a having a small heat capacity is formed by coating an emitter whose main component is Cs ₂ O, which is an alkali metal oxide having a low work function in which the outermost shell electrons are easily emitted, the filament 6a is heated to the arc transition temperature. The warm time becomes shorter. When a high voltage is applied between the electrodes 3 and 3 at the time when the filament 6a having a small heat capacity reaches the arc transition temperature, the fluorescent lamp 1 is started and high frequency lighting is performed.

After the fluorescent lamp 1 is turned on, the bimetal 7 is struck by the high density plasma of negative glow to be thermally deformed, and the wells 5b connecting the filament 6a having a small heat capacity to the filament 6b having a large heat capacity are connected. Switch to Wells 5c. By this switching, the commercial AC current is applied to the filament 5c having a high heat capacity, which is preheated by being hit by the plasma of the negative glow having a high density, and the high frequency lighting of the fluorescent lamp 1 is maintained.

This switching time, that is, the time between the bimetal 7 and the wells 5b connecting the filaments 6a having a small heat capacity to the filaments 5b having a large heat capacity and contacting the filaments 5b having a large heat capacity is less than a millisecond. Therefore, the fluorescent lamp 1 does not seem to go out.

According to the above-mentioned embodiment, in addition to the filament 6b having a large heat capacity and a long life, the emitter is coated in a large amount,
By providing a filament 6a with a small heat capacity, which is formed by coating with a reduced amount of emitters, and switching the energization to these filaments 6a and 6b from 7 to bimetal, the filament 6a with a small heat capacity is energized at startup and the temperature is raised in a short time. Then, the filament 6b having a long heat capacity and a large heat capacity is energized to maintain the lighting after the lighting, so that both the lighting in a short time and the extension of the life can be achieved.

Further, the filament 6a having a small heat capacity
Has an emitter mainly composed of an oxide of an alkali metal such as Cs ₂ O having a low work function, the arc transition temperature is reached and the fluorescent lamp 1 is turned on in a shorter time. It can be further improved.

Since the fluorescent lamp 1 is lit at a high frequency by a high-frequency lighting circuit (not shown), the fluorescent lamp 1 having preheating conditions conforming to international standards and having a long life can be easily lit at a high frequency. Then, due to the long life of the fluorescent lamp 1 having an excellent startability, the fluorescent lamp 1 mounted on the fixture body (not shown)
Therefore, the frequency of exchanging is reduced and operability can be improved.

Although the pair of electrodes 3 and 3 are each provided with two filaments 6a in the description, only one electrode is 2
The same effect can be obtained by providing only the filament 6b having a large heat capacity on the other electrode 3 by providing the filament 6b of the book. Further, with this configuration, the fluorescent lamp 1 can be formed at low cost.

It is also possible to provide a high-frequency lighting circuit outside the main body of the fixture without providing the high-frequency lighting circuit in the main body of the instrument to which the fluorescent lamp 1 is mounted, and to turn on the high-frequency lighting of the fluorescent lamp 1 in this high-frequency lighting circuit. Furthermore, the fluorescent lamp 1 can also be used in a main body of a device that is not turned on at a high frequency, and even with this configuration, a short start time and a long life can be obtained.

Next, the structure of another embodiment of the fluorescent lamp of the present invention will be described with reference to FIGS.

FIG. 5 is a side view showing another embodiment of the fluorescent lamp of the present invention with a part cut away near one end. Further, FIG. 6 is an explanatory diagram showing a connection state between the filament and the bimetal of the fluorescent lamp shown in FIG.

In FIGS. 5 and 6, reference numeral 11 denotes a fluorescent lamp. In this fluorescent lamp 11, as in the embodiment shown in FIGS. 1 to 4, a rare gas is enclosed and a fluorescent substance film is formed on the inner surface of the fluorescent lamp. It has an elongated glass tube 12.

Further, a pair of electrodes 13, 13 which are discharge means for generating positive column discharge are provided at both ends of the glass tube 12, and these electrodes 13, 13 are provided at both ends of the glass tube 12. Are installed on the stems 14 and 14 for sealing. Then, the electrode 13 has three wells 15 supported by the stem 14.
It is composed of a, 15b, 15c and two filaments 16a, 16b whose ends are connected to the wells 15a, 15b, 15c.

The two filaments 6a and 6b are shown in FIG.
To the same as the embodiment shown in FIG.
A filament 16a having a small heat capacity for coating and forming an emitter (not shown) containing an alkali metal oxide such as s ₂ O as a main component, and (Ba, Sr, Ca) O having a larger work function than the alkali metal oxide are mainly used. A filament with a large heat capacity, which is formed by coating a larger amount of emitters (not shown) than the filament 16a with a small heat capacity
It consists of 16b. The filament 16a with a small heat capacity
Has a resistance value of, for example, 1Ω, and a filament having a large heat capacity has a resistance value of, for example, 3Ω.

Further, the wells 15a, 15b, 15c each have one end projecting from the end of the stem 14 along the tube axis direction of the glass tube 12 to form outer leads 15a1, 15b1, 15c1 and the other end of the glass tube. Inner leads 15 located within 12
The stem 14 is formed by forming a2, 15b2, and 15c2.
The ends of the inner leads 15a2 of the wells 15a are electrically and mechanically connected to one ends of the two filaments 16a and 16b. Meanwhile, Wells 15
The other ends of the filament 16a having a small heat capacity and the filament 16b having a large heat capacity are separately electrically and mechanically connected to the tips of the inner leads 15b1 and 15c1 of the b and 15c, respectively.

Also, the outer lead 15b2 of the wells 15b
A positive temperature coefficient thermistor 17 as a heat sensitive element is provided at the base end portion of the stem 4 side. The tip of the outer lead 15c2 of the wells 15c is electrically and mechanically connected to the tip side of the positive temperature coefficient thermistor 17 of the outer lead 15b2 of the wells 15b.

Further, at both ends of the glass tube 12, as shown in FIG.
As in the embodiment shown in FIG. 4 to FIG. 4, there are provided bases 19 for covering both ends of the glass tube 12. Furthermore, this base 19
On the end surface of the glass tube 12 protruding along the tube axis direction of the glass tube 12
A lamp pin 20 is provided as a book input terminal.
The outer leads 15a1 of the wells 15a and the outer leads 15b1 of the wells 15b are electrically and mechanically connected to the lamp pins 20 and 20, respectively.

The positive temperature coefficient thermistor 17 has a resistance value set to, for example, about 0.5Ω at room temperature, and the sum of the resistance value of the filament 16a having a small heat capacity and the resistance value of the positive temperature coefficient thermistor 17 has a large heat capacity. It is smaller than the resistance value of 16b. Therefore, when AC power is applied between the lamp pins 20 and 20, a filament with a small heat capacity is used.
The current flows through 16a. Furthermore, when a certain amount of heat is applied to the PTC thermistor 17, the resistance value of the PTC thermistor 17 increases, and the sum of the resistance value of the filament 16a having a small heat capacity and the resistance value of the PTC thermistor 17 is the heat capacity. It is larger than the resistance value of the large filament 16b. Therefore, when an AC power supply is applied between the lamp pins 20, 20, the current flowing through the filament 16a having a small heat capacity has a changeover switch function in which the current flows through the filament 16a having a large heat capacity.

In the fluorescent lamp 11, the lamp pins 20, 20 of the base 19 are connected to the opposing lamp sockets of the main body of the equipment having a high-frequency lighting circuit (not shown), and the fluorescent lamps 11 are mounted between the lamp sockets to be lit at a high frequency.

Next, the operation of the embodiment shown in FIGS. 5 and 6 will be described.

A high-frequency AC power supply is applied between the lamp pins 20 and 20 of the fluorescent lamp 11 mounted on the apparatus body (not shown). One electrode 13 on the side to which this high-frequency AC power is applied
Serves as a cathode and the other electrode 13 serves as an anode. The pair of electrodes 13, 13 makes it easy for a current to flow to the filament 16a having a small heat capacity due to the positive temperature coefficient thermistor 17, so that the high frequency AC power is applied to the filament 16a having a small heat capacity of the electrode 13 serving as the cathode. . At this point, some current also flows through the filament 16b having a large heat capacity.

As a result, a filament having a small heat capacity
The temperature rise rate of 16a is faster, and because the heat capacity is smaller, the emission temperature is reached immediately. Further, since the filament 16a having a small heat capacity is formed by coating an emitter whose main component is Cs ₂ O, which is an alkali metal oxide having a low work function in which the outermost shell electrons are easily emitted, the filament 16a is heated to the emission temperature. The time becomes shorter. When the filament 16a having a small heat capacity reaches the emission temperature, the fluorescent lamp 11 is started and turned on at a high frequency. When the filament 16a having a small heat capacity is energized, a current also flows through the positive temperature coefficient thermistor 17,
The temperature of the positive temperature coefficient thermistor 17 rises and the resistance value increases. Further, the temperature rise of the filament 16a having a small heat capacity is transmitted to the positive temperature coefficient thermistor 17, and
The temperature rise of 17 is accelerated.

Due to the increase in the resistance value due to the temperature rise of the positive temperature coefficient thermistor 17, the current gradually becomes difficult to flow in the filament 16a having a small heat capacity, and the current easily flows in the filament 16b having a large heat capacity. A current also flows through the filament 16b having a large heat capacity, the temperature of the filament 16b itself rises, and the heat due to the temperature rise of the filament 16a having a small heat capacity is transferred, and the temperature of the filament 16b having a large heat capacity gradually rises. Then, when the positive temperature coefficient thermistor 17 reaches a predetermined temperature, the filament 16a having a small heat capacity has a current flow.
Is switched to the filament 16b having a large heat capacity, and a large amount of current flows through the filament 16b having a large heat capacity, and the high-frequency lighting of the fluorescent lamp 11 is maintained by the filament 16b having a large heat capacity.

When the current is switched from the filament 16a having a small heat capacity to the filament 16b having a large heat capacity, the resistance value of the positive temperature coefficient thermistor 17 continuously changes, so that the fluorescent lamp 11 does not go out due to the current switching. .

When the fluorescent lamp 11 is turned on, the resistance of the positive temperature coefficient thermistor 17 has a large heat capacity and the filament 16b has a large heat capacity.
Since the minute current flows through the filament 16a, which has a small heat capacity, even if it exceeds the resistance value of
This minute current also flows through 17. Therefore, the resistance value of the positive temperature coefficient thermistor 17 is unlikely to decrease, and the filament 16b having a large heat capacity can be stably energized, and stable and good illumination can be obtained.

The embodiment shown in FIGS. 5 and 6 is similar to that shown in FIG.
As in the embodiment shown in FIG. 4, at the time of starting, the filament 16a having a small heat capacity is energized to raise the temperature in a short time to be lit, and after the lighting, the filament 16b having a long life and a large heat capacity is energized to be lit. By maintaining it, it is possible to achieve both lighting in a short time and extension of life.

The filament 16a having a small heat capacity
In addition, since an emitter mainly composed of an oxide of an alkali metal having a low work function is formed by coating, the temperature can be raised in a shorter time and the startability can be further improved.

Since the fluorescent lamp 1 is lit at a high frequency by a high-frequency lighting circuit (not shown), the fluorescent lamp 1 that meets the international standards of preheating conditions and has a long life can be easily lit at a high frequency, and the fluorescent lamp is excellent in startability. Due to the extension of the life of the fluorescent lamp 1, the frequency of exchanging the fluorescent lamp 1 mounted on the fixture body (not shown) is reduced and the operability can be improved.

It should be noted that in the embodiments shown in FIGS. 1 to 4, the energization of filaments having different heat capacities is switched by a bimetal as a heat sensitive element, and in the embodiments shown in FIGS. 5 and 6, a positive temperature coefficient thermistor is used as a heat sensitive element. Although the energization of filaments having different heat capacities is switched, the thermosensitive element may have any switch function as long as it is switched by heat from the outside or heat caused by self-heating.

Further, in the embodiments shown in FIGS. 1 to 4 and the embodiments shown in FIGS. 5 and 6, a time constant circuit is provided in the electrode instead of the heat sensitive element, and the time constant circuit is used for a predetermined time. After the passage, the filament 6a with a small heat capacity,
A switching element such as a transistor for switching the energization from 16a to the filaments 6b and 16b having a large heat capacity can be provided in the electrode.

[0062]

According to the fluorescent lamp of the first aspect, the filament having a small heat capacity is connected to the input terminal through the thermosensitive element for starting and lighting, and after the lighting, the filament by which the thermosensitive element is large is inputted by the heat generated by lighting. Since the connection to be connected to the terminal is switched, the filament is heated quickly with a small heat capacity filament at the time of starting, and after lighting, it is maintained with a filament with a long heat capacity and a large heat capacity. Can be achieved.

According to the fluorescent lamp of the second aspect, the filament having a small heat capacity is connected to the input terminal by the switching element at the time of starting, and the time constant circuit causes the filament having a large heat capacity at the switching element after a predetermined time elapses. Since it is switched and connected to the input terminal, it is lit with a filament with a small heat capacity that is fast in preheating at the time of starting, and is maintained with a filament with a large heat capacity that has a long life after lighting. be able to.

According to the fluorescent lamp of claim 3, in addition to the effect of claim 1 or 2, the filament having a low heat capacity is formed by coating the filament with an emitter mainly composed of an oxide of an alkali metal having a low work function. Since it is formed, the temperature can be raised in a short time and the startability can be improved.

According to the lighting equipment of the fourth aspect, since the fluorescent lamp having the excellent startability according to any one of the first to third aspects is attached to the main body of the lighting equipment, the frequency of exchanging the fluorescent lamp can be reduced and the operability can be reduced. Can be improved.

According to the lighting device of the fifth aspect, in addition to the effect of the fourth aspect, since the fluorescent lamp is lit at a high frequency, the life of the fluorescent lamp for high frequency lighting whose preheating condition conforms to the international standard can be extended. .

According to the luminaire of claim 6, in addition to the effect of claim 4 or 5, since the fluorescent lamp is lit at a high frequency by the high frequency lighting circuit, the preheating condition conforms to the international standard and the fluorescent light has a long life. The lamp can be easily lit at high frequency.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a fluorescent lamp of the present invention with a part cut away near one end.

FIG. 2 is a side view showing the same fluorescent lamp as above, with a portion near one end cut away.

FIG. 3 is an axial sectional view showing the above fluorescent lamp.

FIG. 4 is an explanatory diagram showing a connection state between a filament and a bimetal of the same fluorescent lamp.

FIG. 5 is a side view showing another embodiment of the fluorescent lamp of the present invention with a part cut away near one end.

FIG. 6 is an explanatory diagram showing a connection state between a filament and a bimetal of the same fluorescent lamp.

[Explanation of symbols]

 1,11 Fluorescent lamp 3,13 Electrode 6a Filament with small heat capacity 6b Filament with large heat capacity 7 Bimetal as heat sensitive element 10, 20 Lamp pin as input terminal 17 Positive temperature coefficient thermistor as heat sensitive element

Claims (6)

[Claims] 1. A pair of input terminals, two filaments having different heat capacities, and a pair of input terminals provided between at least one of the input terminals and at least one of the two filaments, and having a small heat capacity at the time of starting. A hot cathode having a heat sensitive element in which a filament is connected to an input terminal and a large heat capacity is connected to the input terminal by heat generated by lighting; and a hot cathode is provided at both ends to form a discharge path, and fluorescent light is provided on the inner surface side. An airtight container having a body layer formed thereon; 2. A pair of input terminals, two filaments having different heat capacities, and a pair of input terminals, which are provided between at least one of the pair of input terminals and at least one of the two filaments. A switching element that connects either one to the input terminal, and a filament with a small heat capacity is connected to the input terminal with the switching element at startup, and a filament with a large heat capacity is input with the switching element after the elapse of a predetermined time after lighting. A hot cathode having a time constant circuit that is switched and connected to a terminal; and an airtight container having a phosphor layer formed on the inner surface side, the hot cathode being provided at both ends to form a discharge path. Fluorescent lamp to do. 3. The fluorescent lamp according to claim 1, wherein the filament having a small heat capacity is coated with an emitter mainly composed of an oxide of an alkali metal. 4. A lighting fixture comprising: the fluorescent lamp according to any one of claims 1 to 3; and a fixture main body on which the fluorescent lamp is mounted. 5. The luminaire according to claim 4, wherein the fluorescent lamp is lit at high frequency. 6. The luminaire according to claim 4, further comprising a high-frequency lighting circuit for lighting the fluorescent lamp at a high frequency.