JP2010050055A - Electrodeless discharge lamp and lighting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrodeless discharge lamp and a lighting apparatus which free of deterioration during a lamp lifetime and can further perform a starting assistance without giving an effect to the luminous efficiency of the lamp. <P>SOLUTION: The electrodeless discharge lamp 10 and the lighting apparatus are provided with a bulb 11, a cavity 12 which forms an airtight space 20 integrally with the bulb 11, an exhaust capillary 24, a coupler 14 consisting of an induction coil 32 to generate induction field in the bulb and a ferrite core 31 wound with the induction coil 31, and a lighting circuit to generate a high frequency current. The coupler 14 is assembled detachably into the lamp part 17 consisting of the bulb 11 and the cavity 12, and discharge gas is excited to emit light by the action of the electromagnetic field generated by the induction coil 32 by the high frequency current supplied from the lighting circuit. A long afterglow phosphor 15 is coated on the external face of the cavity 12 and a heater 16 is installed on the coupler 14 side interposing the cavity 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrodeless discharge lamp and a lighting fixture that excites a discharge gas by an electromagnetic field formed by energizing a high-frequency current to an induction coil without having an electrode.

  In general, an electrodeless discharge lamp is composed of a bulb enclosing discharge gas and mercury vapor and an induction coil, and the mercury vapor is excited by a high-frequency electromagnetic field generated by flowing a high-frequency current through the induction coil. The emitted ultraviolet light is converted into visible light by the phosphor. Such an electrodeless discharge lamp has a structure that does not have an electrode inside, and therefore does not turn off due to electrode deterioration, and has a longer life than a general fluorescent lamp.

  On the other hand, an initial electron generation source such as a hot electrode of a fluorescent lamp having a normal electrode does not exist in the bulb of the electrodeless lamp, and discharge is started by an electron that exists by chance in the bulb. In a bright place, the discharge gas in the bulb is ionized to some extent by ultraviolet rays and visible light hitting the bulb, and there are relatively many initial electrons, so the time until the lamp starts is relatively short. On the other hand, in a dark place, there is little ultraviolet light and visible light, the discharge gas of the bulb is hardly ionized, and there are few initial electrons, so the time until the lamp starts is long.

  Therefore, in a conventional electrodeless discharge lamp, a dark place starting auxiliary material is used in order to shorten the lighting start time in the dark place. Examples of dark starting aids include radioactive materials such as Kr85, simple metals with low work functions such as cesium (Cs) and sodium (Na) or their oxides, and long afterglow phosphors and phosphorescent members. is there. Of these, there is a desire to avoid the use of radioactive materials because of the dangers to the human body.

  As an example of conventional electrodeless discharge lamps and lighting fixtures, there is an electrodeless discharge lamp in which a container with a starting aid adhered is accommodated in an arc tube (see, for example, Patent Document 1).

  As another example of conventional electrodeless discharge lamps and lighting fixtures, there is an electrodeless discharge lamp in which a dark place starting auxiliary body is fixed to a holding body attached to the upper part of a vent pipe (for example, see Patent Document 2).

As another example of conventional electrodeless discharge lamps and lighting fixtures, there is an electrodeless discharge lamp in which a phosphor layer containing a long afterglow phosphor is applied to the outer periphery of an inner tube (see, for example, Patent Document 3).
JP 2002-260594 A (FIG. 1, paragraph number 0010) Japanese Patent Laying-Open No. 2005-123157 (FIG. 1, paragraph number 0031) JP 2004-234945 A (FIG. 1, paragraph number 0013)

  However, the electrodeless discharge lamp disclosed in Patent Document 1 uses a container having an opening as a holding body. Although it is possible to reduce the degree of spattering by this, it is necessary to dispose in the vicinity of the plasma in order to ensure sufficient start-up assisting performance, so deterioration during the life cannot be avoided. For example, 60,000 hours or 10 With long-life lamps such as 10,000 hours, there is a risk that start delays in the dark cannot be avoided.

  In the electrodeless discharge lamp disclosed in Patent Document 2, when a mesh is used as a holding body, a material having a low work function may be scattered from the mesh due to sputtering caused by discharge. In order to avoid this, when a holding body is provided at a location away from the discharge, there is a possibility that the start assist performance is not sufficient. In addition, when a holding body having an opening is used for such an electrodeless discharge lamp, the holding body itself becomes heavy, and there is a concern that the size of the holding body may be increased in order to increase the strength of the support structure of the holding body.

  On the other hand, the electrodeless discharge lamp disclosed in Patent Document 3 includes a long afterglow phosphor in the phosphor applied to the recessed portion, and emits electrons by a photoelectric effect due to the afterglow of the long afterglow phosphor. However, although the start delay in the dark place can be improved, the long afterglow phosphor is inferior to the commonly used rare earth phosphor, and thus the luminous efficiency of the lamp may be lowered. is there.

  The present invention has been made to satisfy the above-described demands, and its purpose is to provide an electrodeless discharge lamp that can be started up without deterioration during the life of the lamp and without affecting the lamp luminous efficiency. It is to provide a luminaire.

  The electrodeless discharge lamp of the present invention has a light-transmitting bulb in which a protective film and a phosphor film are applied to the inner wall, and a cavity that is coated with the protective film and the phosphor film to form an airtight space integrally with the bulb. The exhaust tube opened from the bottom of the cavity toward the top and containing mercury enclosed in a discharge gas and a metal container, an induction coil for generating an induction electric field in the bulb, and the induction coil were wound A coupler comprising a ferrite core and a lighting circuit for generating a high-frequency current, wherein the coupler is detachably assembled to the lamp portion comprising the bulb and the cavity, and the induction is performed by the high-frequency current supplied from the lighting circuit. In an electrodeless discharge lamp that excites and emits the discharge gas by the action of an electromagnetic field generated by a coil, a long afterglow phosphor is applied to the outer surface of the cavity. Characterized in that a heater on the coupler side across the cavity.

In the present invention, by providing a heater on the coupler side across the cavity with respect to the long afterglow phosphor applied to the outer surface of the cavity, a material having a low work function such as cesium as a starting aid is used as a starting aid. Compared to the structure, there is no problem of scattering or deterioration due to the life of the sputtering.
Therefore, it is possible to ensure a stable starting performance in a dark place during the lifetime.

  The electrodeless discharge lamp of the present invention is characterized in that the heater is driven through a resonance circuit that operates in resonance with a starting oscillation frequency before the lamp is lit.

  In the present invention, since the heater can be heated only at the time of starting by being driven through a resonance circuit that operates by resonating with the starting oscillation frequency before the lamp is lit, the long afterglow phosphor is deteriorated. The starting performance in a dark place that is more stable during the lifetime can be secured.

  The electrodeless discharge lamp of the present invention is characterized in that the resonance circuit is provided with a heat sensitive element whose resistance value can be varied according to temperature.

  In the present invention, the resonance circuit is provided with a thermosensitive element such as a PTC thermistor whose resistance value varies depending on the temperature, so that the resistance value becomes high when the lamp temperature is high and the resistance value becomes low when the lamp temperature is low. By lowering the temperature, the heater can be heated at a low temperature to activate the long afterglow phosphor, and the dark startability can be ensured by the initial electrons emitted from the long afterglow phosphor.

  The lighting fixture of the present invention uses the electrodeless discharge lamp of the present invention.

  In the present invention, by providing a heater on the coupler side across the cavity with respect to the long afterglow phosphor applied to the outer surface of the cavity, it is possible to provide a luminaire that ensures stable starting performance in a dark place until the end of its lifetime. .

According to the electrodeless discharge lamp and the lighting fixture of the present invention, the long afterglow phosphor is applied to the outer surface of the cavity, and the heater is provided on the coupler side across the cavity.
As a result, there is no deterioration during the life of the lamp, and there is an effect that the starting assistance can be performed without affecting the lamp luminous efficiency.

  Hereinafter, an electrodeless discharge lamp and a lighting fixture according to a plurality of embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the luminaire 1 according to the first embodiment of the present invention has an electrodeless discharge lamp 10 assembled in a lamp chamber 4 sealed with a reflector 2 and a front panel 3. The electrodeless discharge lamp 10 is electrically connected to the lighting circuit 5 outside the lighting fixture 1, and the lighting circuit 5 is electrically connected to a wiring device (not shown) provided on the ceiling or wall surface.

  As shown in FIGS. 2, 3, and 4, the electrodeless discharge lamp 10 according to the first embodiment of the present invention has a spherical bulb 11 and a hollow portion 13 formed in the center of the bulb 11. And a coupler 14 fitted in the hollow portion 13, a long afterglow phosphor 15, and a heater 16. The bulb 11 and the cavity 12 constitute a lamp portion 17, and the lamp portion 17 is assembled to the coupler 14 in a separable manner.

  The bulb 11 and the cavity 12 are formed using a light-transmitting glass material, and the neck portion 18 on the lower end side of the bulb 11 and the flange portion 19 on the lower end of the cavity 12 are melted and sealed, A sealed space 20 is formed inside the valve 11. The sealed space 20 is filled with 40 Pa of argon as a discharge gas. A protective film 22 and a phosphor film 23 are laminated and applied to the inner surface 21 of the bulb 11.

  The cavity 12 is a cylindrical body whose upper end is closed, and a bottomed exhaust thin tube 24 is provided at the center thereof. Therefore, a hollow portion 13 having a substantially donut shape in a horizontal section view is formed inside the cavity 12.

  In the exhaust narrow tube 24, a Bi (bismuth) -In (indium) -Hg (mercury) compound having a total amount of about 200 mg and a content ratio of 5% is accommodated in a metal container 25 in order to release mercury. A glass rod 26 for positioning the metal container 25 is accommodated.

  On the outer peripheral surface of the cavity 12, a protective film 27, a short afterglow phosphor 28 and a long afterglow phosphor 29 are laminated and applied in two or three layers on the upper part, and the entire outer periphery of the lower part thereof is applied. The long afterglow phosphor 15 is applied. This is because the luminous efficiency of the long afterglow phosphor 15 is not good, and if applied near the plasma, the luminous efficiency of the lamp may be reduced.

  The long afterglow phosphor 15 as a dark place starting auxiliary material has an afterglow time of a general phosphor (the time from when the excitation light is blocked until the emission intensity is attenuated to 1/10) of several tens of milliseconds. On the other hand, it is very long and tens of minutes.

Examples of the long afterglow phosphor 15 include europium and disbrosium co-activated strontium aluminate phosphors (SrAl ₂ O ₄ : Eu, Dy, Sr ₄ Al ₁₄ O ₂₅ : Eu, Dy), europium, and neodymium. Examples include a co-activated calcium aluminate phosphor (CaAl ₂ O ₄ : Eu, Nd). These phosphors are particularly excited by near ultraviolet rays (wavelength 300 to 380 nm) and emit light. However, since the low-pressure mercury discharge of the electrodeless discharge lamp 10 of the present embodiment also includes light emission of the same wavelength, it is long. The afterglow phosphor 15 can be excited. Thus, it was confirmed that the long afterglow phosphor 15 can maintain afterglow for a very long time even after the lamp is turned off, and that the start-up delay can be suppressed even in a dark place by the electrons generated by the afterglow. The long afterglow phosphor 15 is more stable than a low work function material such as a cesium compound.

  The coupler 14 includes a cylindrical heat radiation cylinder 30, a cylindrical ferrite core 31 fitted on the upper end side of the heat radiation cylinder 30, and an induction coil 32 wound around the outer periphery of the ferrite core 31. ing.

  Since the high frequency current passed through the induction coil 32 is a low frequency on the order of several hundred Hz, the magnetic core of the ferrite core 31 is disposed in the induction coil 32.

  A heater 16 is disposed opposite to the long afterglow phosphor 15 across the cavity 12.

  Each part of the coupler 14 has an annular shape when viewed from the horizontal cross section, and its outer diameter is set slightly smaller than the inner diameter of the hollow part 13 of the cavity 12. Further, the inner diameter of the heat radiating cylinder 30 is set slightly larger than the outer diameter of the exhaust thin tube 24. Thereby, the coupler 14 can be fitted into the hollow portion 13 of the cavity 12.

  A base 33 is provided at the lower end of the lamp unit 17, and the lamp unit 17 and the coupler 14 are coupled by the base 33.

  As shown in FIG. 5, the heater 16 is connected to the secondary coil 34 in series. The secondary coil 34 is wound around the ferrite core 31 on the lower side of the induction coil 32. Therefore, the heater 16 is driven by receiving the induced electromotive force from the induction coil 32 at the start before the lamp is turned on, and activates the long afterglow phosphor 15 disposed opposite to the heater 16.

  In such an electrodeless discharge lamp 10, a high frequency magnetic field is generated around the induction coil 32 by supplying high frequency power from the lighting circuit 5 to the induction coil 32. Electrons in the sealed space 20 are accelerated by the high-frequency magnetic field, and the gas is ionized by the collision of the electrons to generate a discharge. Further, during discharge, the rare gas is excited, and the excited atoms generate ultraviolet rays when returning to the ground state. This ultraviolet light is converted into visible light by the phosphor film 23 applied to the inner wall of the bulb 11. The converted visible light passes through the bulb 11 and is emitted to the outside.

At this time, the heater 16 is driven by the induced electromotive force from the induction coil 32 and the long afterglow phosphor 15 is activated at the start before the lamp is lit.
Therefore, the initial electrons generated from the long afterglow fluorescent lamp 15 at the time of start-up before the lamp is turned on promote the discharge at the time of subsequent turn-on and improve the start-up performance in the dark place.

According to the electrodeless discharge lamp 10 of the first embodiment described above, the heater 16 is provided on the coupler 14 side with the cavity 12 interposed between the long afterglow phosphor 15 applied to the outer surface of the cavity 12.
As a result, the problem of scattering and deterioration due to the splatter during the life is eliminated, as compared with the conventional case where a material having a low work function such as cesium is used as a starting auxiliary material and a mesh structure.
Therefore, it is possible to ensure a stable starting performance in a dark place during the lifetime.

  Moreover, according to the lighting fixture 1 of 1st Embodiment, the electrodeless discharge lamp 10 which provided the heater 16 in the coupler 14 side is equipped with the cavity 12 with respect to the long persistence fluorescent substance 15 apply | coated to the outer surface of the cavity 12. As a result, it is possible to provide the luminaire 1 that ensures stable starting performance in a dark place until the end of its life.

(Second Embodiment)
Next, an electrodeless discharge lamp and a lighting fixture according to a second embodiment of the present invention will be described. In the following embodiments, components that are the same as those in the first embodiment described above or functionally similar components are simplified or omitted by giving the same reference numerals or equivalent symbols in the drawings. To do.

  As shown in FIG. 6, the electrodeless discharge lamp 40 according to the second embodiment of the present invention has a heater 16 connected to a resonance circuit 42 including a secondary coil 41 and a capacitor C <b> 1.

As shown also in FIG. 7, the heater 16 resonates at the time t <b> 1 with respect to the starting frequency f <b> 1 before the lamp is lit, and the heater 16 is heated by the heat of the heater 16. The long afterglow phosphor 15 is activated. Thereafter, the electrodeless discharge lamp 10 is lit at time t2 with the frequency f2.

  According to the electrodeless discharge lamp 40 of the second embodiment, the heater 16 is driven through the resonance circuit 42 that operates in resonance with the oscillation frequency at start-up before the lamp is lit, thereby heating the heater 16 only at start-up. Therefore, it is possible to reduce the deterioration of the long afterglow phosphor 15 and to secure the starting performance in a dark place that is more stable during the lifetime.

(Third embodiment)
Next, an electrodeless discharge lamp and a lighting fixture according to a third embodiment of the present invention will be described.

  As shown in FIG. 8, the electrodeless discharge lamp 50 according to the third embodiment of the present invention has a heater 16, a resonance circuit 42 including a secondary coil 41 and a capacitor C <b> 1, and a resistance value that varies depending on the ambient temperature. For example, a thermal temperature sensing element 51 such as a PTC thermistor is connected.

  The thermosensitive element 51 has a high resistance value when the lamp temperature is high, and a low resistance value when the lamp temperature is low.

  When the electrodeless discharge lamp 50 is started in a dark place, the heater 16 is heated by the resistance value of the thermosensitive element 51 being lowered, and the long afterglow phosphor 15 is activated by the heat of the heater 16, thereby causing long afterglow. The initial electrons generated from the fluorescent lamp 15 promote the subsequent discharge during lighting.

  According to the electrodeless discharge lamp 50 of the third embodiment, the long afterglow phosphor is obtained by heating the heater 16 at a low temperature by connecting the thermal sensor 51 whose resistance value varies with temperature to the resonance circuit 42. 15 can be activated by the initial electrons emitted from the long afterglow phosphor 15 by activating 15.

  In addition, the valve | bulb 11, the nozzle | cap | die 33, etc. which were used in each said embodiment are not limited to what was illustrated, and can be changed suitably.

External view of the lighting fixture to which the electrodeless discharge lamp of the first embodiment according to the present invention is applied The longitudinal cross-sectional view explaining the internal structure of the electrodeless discharge lamp of 1st Embodiment which concerns on this invention Longitudinal sectional view of the lamp part of the electrodeless discharge lamp of FIG. Longitudinal sectional view of the coupler of FIG. Circuit diagram of the heater applied to the electrodeless discharge lamp of FIG. The circuit block diagram of the heater applied to the electrodeless discharge lamp of 2nd Embodiment which concerns on this invention Frequency characteristics diagram of the electrodeless discharge lamp of FIG. The circuit block diagram of the heater applied to the electrodeless discharge lamp of 3rd Embodiment which concerns on this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lighting fixture 5 Lighting circuit 10, 40, 50 Electrodeless discharge lamp 11 Valve 12 Cavity 14 Coupler 15 Long afterglow fluorescent substance 16 Heater 20 Sealed space (airtight space)
22, 27 Protective film 23 Phosphor film 24 Exhaust capillary 25 Metal container 28 Short afterglow phosphor film (phosphor film)
29 Long afterglow phosphor film (phosphor film)
31 Ferrite core 32 Inductive coil 42 Resonant circuit 51 Thermal sensor

Claims (4)

A bulb having translucency and having a protective film and a phosphor film applied to the inner wall;
A cavity for applying a protective film and a phosphor film to form an airtight space integrally with the bulb;
An exhaust tube containing mercury that is opened from the bottom of the cavity toward the top and is enclosed in a discharge gas and a metal container;
An induction coil for generating an induction electric field in the bulb, a coupler comprising a ferrite core around which the induction coil is wound,
A lighting circuit that generates a high-frequency current;
With
The coupler is detachably assembled to the lamp part composed of the bulb and the cavity,
In an electrodeless discharge lamp for exciting and emitting the discharge gas by the action of an electromagnetic field generated by the induction coil by the high-frequency current given from the lighting circuit,
Apply a long afterglow phosphor on the outer surface of the cavity,
An electrodeless discharge lamp, wherein a heater is provided on the coupler side with the cavity interposed therebetween.   2. The electrodeless discharge lamp according to claim 1, wherein the heater is driven through a resonance circuit that resonates and operates at a starting oscillation frequency before the lamp is lit.   The electrodeless discharge lamp according to claim 2, wherein the resonance circuit includes a thermosensitive element whose resistance value can be varied according to temperature.   A lighting fixture using the electrodeless discharge lamp according to any one of claims 1 to 4.

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