JP2002313285A - Dielectric body barrier discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric body barrier discharge lamp, in which discharge start is stable and discharge can be achieved surely. SOLUTION: The dielectric body barrier discharge lamp comprises a discharge container (1), of which at least a part also constitutes a dielectric of dielectric barrier discharge, a discharge gas which is filled in the discharge container (1) and forms excimer molecules by dielectric barrier discharge, and a pair of electrodes (14, 15) that are arranged on the outer face of the discharge container (1). The discharge lamp is characterized, by having a conductor (16) which contacts the inner part of the container opposing the above electrodes (14, 15) in the discharge container (1). The dielectric barrier discharge lamp has stable discharging and has high luminous efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric barrier discharge lamp. In particular, for example, a kind of discharge lamp used as an ultraviolet light source for photochemical reaction, which forms excimer molecules by dielectric barrier discharge, and improves a so-called dielectric barrier discharge lamp using light emitted from the excimer molecules. About.

[0002]

2. Description of the Related Art As a technique related to the present invention, there is, for example, JP-A-2-7353, in which a discharge vessel is filled with a discharge gas for forming excimer molecules, and a dielectric barrier discharge (also known as a dielectric barrier discharge). Ozonizer discharge or silent discharge. An excimer molecule that forms excimer molecules by the revised edition of “Discharge Handbook” published by the Institute of Electrical Engineers of Japan, page 263, reprinted in June 2001, and emits light emitted from the excimer molecules. It describes a body-barrier discharge lamp and is useful because it has various features not found in conventional low-pressure mercury discharge lamps and high-pressure arc discharge lamps.

However, as the output of the dielectric barrier discharge lamp is increased, the discharge gap length is increased and the pressure of the filled gas is increased. As a result, the discharge starting voltage and the input voltage during normal lighting are also increased. For this reason, there is a strong demand for boosting transformers included in lamp lighting devices to have high performance.

Here, in order to reliably light the dielectric barrier discharge lamp, a step-up transformer capable of generating a voltage sufficiently higher than the discharge starting voltage of the dielectric barrier discharge lamp must be used. However, in order to generate a high voltage in a step-up transformer, it is necessary to increase the number of coil windings, which leads to an increase in the size of the transformer itself. In addition, a method of reducing the coil diameter is also conceivable. However, since the electric resistance increases, another problem occurs that heat is generated from the transformer. For this reason, it is not preferable to design a boosting transformer capable of generating a voltage sufficiently higher than the discharge starting voltage as a means for reliably lighting the dielectric barrier discharge lamp, and it is not preferable to reduce the discharge starting voltage itself. A method for ensuring reliable lighting is being studied.

As one method for lowering the discharge starting voltage of such a dielectric barrier discharge lamp, a method has been proposed in which a constricted portion is provided in a part of the discharge space to thereby enhance the lighting startability. The technology is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-209131. The technology described in this document is based on forming a projection with the wall of a discharge vessel itself, which is a dielectric, facing inward, or forming titanium oxide or titanium oxide. That is, a dielectric material made of aluminum oxide is disposed in the discharge space. In other words, a technical idea is disclosed in which a part of the discharge space is designed to be located at a short distance from the other part when discharging between the dielectrics via the discharge space.

However, the dielectric material itself constituting the discharge vessel originally has a variation in its thickness. Due to this variation, the distance of the discharge space (the distance in the discharge direction) is not completely equal in the entire discharge region. Absent. Therefore, even if a part of the discharge space is locally shortened as in the above-described prior art, the discharge space is not necessarily shortened as desired due to variations in the thickness of the dielectric material. However, this causes a problem that discharge cannot be started satisfactorily. In a lighting device for lighting a dielectric barrier discharge lamp, there is no problem if there is an environment in which a sufficient voltage supply is allowed.However, due to the miniaturization of the device and the problem of heat generation, it is ensured that the discharge starting voltage is as small as possible. In a situation where a structure capable of lighting is strongly demanded, such a difference in characteristics due to the variation of the dielectric material has a great influence.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric barrier discharge lamp in which discharge starting can be stably and reliably achieved.

[0008]

In order to solve the above-mentioned problems, a dielectric barrier discharge lamp according to the present invention includes a discharge vessel at least partially serving also as a dielectric of a dielectric barrier discharge,
In a dielectric barrier discharge lamp comprising a discharge gas filled in the discharge vessel to form excimer molecules by dielectric barrier discharge and a pair of electrodes arranged on the outer surface of the discharge vessel, Is characterized by having an electric conductor (hereinafter, also simply referred to as “conductor”) that comes into contact with the inner surface portion of the container facing the electrode.

Further, the conductor is characterized by being springy. A conductor holding member is provided outside the discharge vessel, and at least one of the conductor and the conductor holding member has a magnetic force to hold the conductor at a predetermined position in the discharge vessel. In addition, the conductor is formed of small pieces, and the inside of the discharge vessel is 90 ° or less, preferably 45 ° with the inner surface.
It is characterized by being arranged at an angle of less than or equal to °. Further, the discharge vessel is a substantially double cylindrical type in which an outer tube and an inner tube are coaxially arranged, and one of the electrodes is arranged on the outer surface of the outer tube and the other electrode is arranged on the outer surface of the inner tube. It is characterized by having a configuration. Further, the conductor has a ring shape, the diameter of which is larger than the sum of the outer diameter of the inner tube of the discharge vessel and the discharge gap length, and the inner surface of the outer tube and the inner surface of the inner tube of the discharge vessel. It is characterized by contact.

[0010]

FIG. 1 is a schematic view of a dielectric barrier discharge lamp according to the present invention. FIG. 1A shows the overall configuration by a cross-sectional view of a dielectric barrier discharge lamp, and FIG.
FIG. 3A is a sectional view taken along line AA ′ of FIG. The dielectric barrier discharge lamp 1 has a cylindrical overall shape, and is made of synthetic quartz glass that functions as a dielectric by dielectric barrier discharge and transmits vacuum ultraviolet light. In the discharge lamp 1, the inner tube 11 and the outer tube 12 are coaxially arranged to form a double cylindrical tube, and since both ends are closed, a discharge space 13 is formed between the inner tube 11 and the outer tube 12.
In the discharge space 13, excimer molecules are formed by dielectric barrier discharge, and a discharge gas, for example, xenon gas, which emits vacuum ultraviolet light from the excimer molecules, is sealed. To give a numerical example, the discharge lamp 1 has a total length of 800 m.
m, the outer diameter is 36 mm, the outer diameter of the inner tube 11 is 16 mm, and the thickness of the inner tube 11 and the outer tube 12 is 2 mm.

A mesh electrode 14 is provided on the outer surface of the outer tube 12, and the inner electrode 1, which is the other electrode, is provided inside the inner tube 11.
5 are provided. The mesh electrode 14 is formed seamlessly and has elasticity as a whole, so that the adhesion to the outer tube 12 can be improved. The inner electrode 15 has a pipe shape or a substantially C-shape having a cutout in a section, and is provided so as to be in close contact with the inner tube 11. Getters are arranged in the discharge space 13 as needed.

An AC power supply (not shown) is connected between the mesh electrode 14 and the inner electrode 15, whereby excimer molecules are formed in the discharge space 13 to emit vacuum ultraviolet light. When xenon gas is used as the discharge gas, the wavelength is 172n.
m light.

In the discharge space 13, a metal piece is provided as a conductor 16 for improving lighting startability, and an inner tube 11 and an outer tube 12 are provided.
It is arranged so that it may contact. The conductor 16
Must be arranged at a position where electrodes exist on the outer surfaces of the inner tube 11 and the outer tube 12. Although this will be described later, since the conductor 16 is a starting point of the dielectric barrier discharge,
This is because it is necessary to be in a state where a voltage is applied from outside the dielectric. The conductor 16 is, for example, platinum,
Gold, tungsten, iron, nickel, stainless steel, inconel, phosphor bronze, tungsten, beryllium copper, etc. are applied, and not only metals generally having an electric resistivity of 10 ⁻⁴ (Ω · cm) or less, but also electric resistivity ^10-3
It also includes a semiconductor defined by 10 ³ (Ω · cm). Further, a conductor may be coated on the surface of a dielectric such as a resin or a glass piece by a method such as vapor deposition.

FIG. 2 shows a state where the portion where the conductor 16 is arranged in FIG. 1 is enlarged. The conductor 16 has, for example, a leaf spring made of stainless steel inserted therein. When a voltage is applied between the outer electrode 14 and the inner electrode 15, a potential is formed on the outer surfaces of the outer tube 12 and the inner tube 11, which are dielectrics, respectively.
Since this potential is also formed on the inner surfaces of the outer tube 12 and the inner tube 11, a discharge D1 is generated from a gap between the conductor 16 and the dielectric. The discharge D1 induces the discharges D2 and D2.
3, and then a discharge D4 occurs between the discharge gaps. Due to the generation of the discharge D4, a discharge is generated in the entire discharge space. That is, the conductor 16
, A dielectric barrier discharge can be satisfactorily generated if a voltage sufficient to generate the discharge D1 is applied. The length X of the conductor 16 (the inner electrode 15
Is, for example, 20 mm, which is extremely smaller than the length (longitudinal direction) of the discharge space, 800 mm. For this reason, once the dielectric barrier discharge lamp starts lighting, the presence of the conductor 16 does not affect the discharge characteristics thereafter. Since the conductor 16 is in contact with the inner tube 11 and the outer tube 12, it is desirable to use a material having elasticity such as a spring material. Even conductor
16 is fixed. Also, the conductor 16 is not only a spring material,
By devising the shape, etc., it is possible to contact the inner tube 11 and the outer tube 12 with a small elastic force such as plastic deformation. 16 is fixed. Since the lamp shown in FIG. 1 has a cylindrical shape as a whole, the end of the conductor 16 may not be completely in contact with the dielectric, but there is no problem if the end is in contact with a part.

Here, the present inventors prefer to arrange a conductor instead of a dielectric in the discharge space, and to bring this conductor into contact with the dielectric constituting the discharge vessel instead of separating it from the starting space. I found that it was effective in terms of sex. Although the technical basis is not always clear, it can be guessed as follows. FIG. 3 is a drawing for explaining the discharge principle of the present invention. Consider a case where an AC voltage V0 is applied between the inner electrode 15 and the outer electrode 14. The thickness of the inner tube 11 and the outer tube 12 is d1, and the distance of the discharge space 13 is d2. The relative permittivity of the discharge space 13 is set to 1,
The relative permittivity of the inner tube 11 and the outer tube 12 is ε1. Here, A is a unit area where no object is present in the discharge space 13, and
The capacitances of the inner tube 11, the discharge space 13, and the outer tube 12 of the unit area A are C1, C2, and C3, respectively, and the voltages applied thereto are ΔV1, ΔV2, and ΔV3. Further, the potential on the discharge space 13 side of the inner tube 11 is V1, and the potential on the discharge space side of the outer tube 12 is V2. ΔV1: ΔV2: ΔV3 = (1 / C1) :( 1 / C2) :( 1 / C3) = (d1 / ε1): d2: (d1 / ε1) V1 = V0 × (ΔV2 + ΔV3) / (ΔV1 + ΔV2 + ΔV3) = V0 × (d1 + ε1 × d2) / (2 × d1 + ε1 × d2) V2 = V0 × ΔV3 / (ΔV1 + ΔV2 + ΔV3) = V0 × d1 / (2 × d1 + ε1 × d2) And the capacitances of the inner tube 11, the outer tube 12 in the unit region B are C4 and C5, respectively, and the voltages applied to the inner tube 11, the conductor 16, and the outer tube 12 in the unit region B are Δ
V4, ΔV5, and ΔV6. Further, the potential on the conductor 16 side of the inner tube 11 is V3, and the potential on the conductor 16 side of the outer tube 12 is V4. ΔV4: ΔV5: ΔV6 = (1 / C4): 0: (1 / C5) = (d1 / ε1): 0: (d1 / ε1) V3 = V0 × (ΔV5 + ΔV6) / (ΔV4 + ΔV5 + ΔV6) = V0 / 2 V4 = V0 × ΔV6 / (ΔV4 + ΔV5 + ΔV6) = V0 / 2 V3 and V4 have the same size. Here, V1−V3
(= ΔV10) and V2−V4 (= ΔV11), ΔV10 = V1−V3 = (V0 × d2 × ε1) / (4 ×
d1 + 2 × d2 × ε1) ΔV11 = V2-V4 = − (V0 × d2 × ε1) / (4
× d1 + 2 × d2 × ε1) Boundary K between the region where the object does not intervene and the region where the conductor intervenes
At 1 and K2, since the potentials of V1 and V3 and V2 and V4 occur at extremely short distances, a strong electric field is locally generated. Discharge can be easily generated by this strong electric field, and this discharge becomes a starting point of discharge in the entire discharge space. Here, ΔV when the distance d2 of the discharge space is ∞
10. When calculating ΔV11, these are respectively V0 /
2, converges to -V0 / 2. This is the distance d of the discharge space
This means that even when the value of 2 becomes large, a local strong electric field serving as a starting point of discharge can be obtained stably.

On the other hand, consider the case where a dielectric is interposed in the discharge space instead of a conductor. The unit region where the dielectric 22 having the relative permittivity ε2 intervenes in the discharge space is C, and the capacitances of the inner tube 11, the dielectric 22, and the outer tube 12 of the unit region C are C6, C7, and C8, respectively. Are ΔV7, ΔV8, and ΔV9. Further, the potential on the dielectric 22 side of the inner tube 11 is V5, and the potential on the dielectric 22 side of the outer tube 12 is V6. ΔV7: ΔV8: ΔV9 = (1 / C6): (1 / C7): (1 / C8) = (d1 / ε1): (d2 / ε2): (d1 / ε1) V5 = V0 × (ΔV8 + ΔV9) / ( ΔV7 + ΔV8 + ΔV9) = V0 × (d2 × ε1 + d1 × ε2) / (d2 × ε1 + 2 × d1 × ε2) V6 = V0 × ΔV9 / (ΔV7 + ΔV8 + ΔV9) = V0 × d1 × ε2 / (d2 × ε1 + 2 × d1 × ε2) V1−V5 (= Δ12), V2−V6 (= Δ1)
When calculating 3), ΔV12 = V1-V5 = {V0 × d1 × d2 × ε1 × (ε2-1)} / ｛(2
× d1 + d2 × ε1) × (d2 × ε1 + 2 × d1 × ε
2) ΔV13 = V2−V6 = − {V0 × d1 × d2 × ε1 × (ε2-1)} /
｛(2 × d1 + d2 × ε1) × (d2 × ε1 + 2 × d1
× ε2)｝ A strong electric field can be locally obtained when a dielectric is interposed instead of a conductor, as in the case of a conductor, but is smaller than that of a conductor. Further, when ΔV12 and ΔV13 are calculated when the distance d2 of the discharge space is ∞, these converge to 0. This means that as the distance d2 in the discharge space increases, the local electric field serving as the starting point of the discharge decreases. In the case of a conductor, the emission of initial electrons from the conductor can be expected, but in the case of a dielectric, the effect cannot be expected. That is, the presence of the conductor in the discharge space means that the lighting can be started with a smaller discharge starting voltage than in the case where the dielectric is provided in the discharge space. This effect becomes more remarkable as the discharge gap increases with the output of the dielectric barrier discharge lamp. In this illustration, the conductor 16 and the inner tube 11 and the conductor 16 and the outer tube 12 each form an angle of 90 °. Although a sufficient effect can be obtained at this angle, if possible, a smaller angle will increase the region where the electric field is strong, so that a better effect can be obtained.

Next, the conductor 16 interposed in the discharge space is
It is necessary to make contact with the inner tube 11 and the outer tube 12 which constitute the dielectric. As can be seen from the above description, it is necessary to make contact with each other in order to further increase the potential difference between the discharge starting points K1 and K2. Will attenuate. Therefore, in the structure in which the protrusion is formed as disclosed in Japanese Patent Application Laid-Open No. 6-209131 introduced in the prior art, even if such a protrusion is formed by a conductor, the discharge is performed by applying the minimum voltage as in the present invention. The effect of achieving the start cannot be expected.

FIG. 9 shows an example for proving such a discharge principle. Potential difference ΔV1 at discharge starting points (K1, K2) when a conductor (for example, platinum or the like) is interposed
0 and the starting point of discharge (K1, K
2) shows the potential difference ΔV12 in 2), and shows values when the distance d2 of the discharge space is changed. In addition, the dielectric material described about titanium oxide (dielectric constant ε = 170) and quartz glass (dielectric constant ε = 3.7). In the figure, the vertical axis shows the potential difference (voltage relative value) at the discharge starting point (applied voltage V
The relative value when 0 is 1) and the horizontal axis is the distance d of the discharge space
2 is shown. In addition, the potential difference (voltage relative value) of the conductor is denoted by A, the potential difference (voltage relative value) of titanium oxide is denoted by B, and the potential difference (voltage relative value) of quartz glass is denoted by C. As a result, it can be seen that the potential difference is larger when the conductor is interposed in the discharge space than when the dielectric is interposed. Further, even if a dielectric having a high dielectric constant such as titanium oxide is interposed, the potential difference between the conductor and the conductor increases as the discharge space d2 increases.

Further, in the present invention, the conductor arranged in the discharge space does not constitute an electrode. Some dielectric barrier discharge lamps have a structure in which one of a pair of electrodes is provided in a discharge space, but the conductor according to the present invention is not such a structure. Also, a metal getter is disposed in order to adsorb impurities in the discharge space, and a metal deposition film is applied for the purpose of shielding light to prevent direct exposure to a specific part of the discharge vessel. Body-barrier discharge lamps exist, which differ from the structure of the present invention in that they are located at positions outside the region where the discharge occurs if electrodes are present, and the conductor of the present invention is a discharge vessel. The configuration is completely different in that it must be in contact with the inner surface that is to face the electrode.

FIG. 4 shows another embodiment of the dielectric barrier discharge lamp according to the present invention, and is a partially enlarged view of one end having a conductor of the discharge lamp shown in FIG. In this embodiment, instead of using a metallic spring member as a conductor, a conductor that forms a magnetic relationship is used. That is, the discharge space 13
And a conductor holding member 17 that arranges the conductor 16 via a dielectric (outer wall of the discharge vessel) to form a magnetic relationship. Then, at least one of the material having the magnetic force and the other ferromagnetic material is fixed with the dielectric therebetween. For example, a samarium-cobalt magnet, an alnico magnet, etc. can be used as a material having a magnetic force.
Nickel, silicon steel, etc. can be used. In addition, even if both are materials having a magnetic force, the present invention can be applied as long as they can be fixed and held together. As described above, the conductor holding member is provided outside the discharge vessel, and the conductor existing inside the discharge vessel (discharge space) has a magnetic relationship to hold the conductor 16 at a predetermined position in the discharge vessel. Becomes possible.

The conductor 16 needs to be in contact with the outer wall of the discharge vessel inside the discharge vessel (in the discharge space), that is, the inner tube 11 and the outer tube 12 in the figure.
Preferably, as shown in the figure, it is preferable that the conductor 16 and the outer wall form an acute angle. This is because such a configuration makes it easier to generate a discharge serving as a starting point. This acute angle is more effective as it is smaller than 90 °, but it has been confirmed that, in a practical sense, when the angle is 45 ° or less, more preferably 30 ° or less, a discharge starting point is remarkably generated. In addition, as shown in FIG.
6, the contact angle between the conductor 16 and the inner tube 11 and the outer tube 12, which is a dielectric, always forms an acute angle of 90 ° or less. In the case where a conductive paste or the like is applied to the end and the dielectric is brought into contact, the contact angle formed by the conductive paste may exceed 90 °. At an acute angle.

FIG. 5 shows another embodiment of the dielectric barrier discharge lamp according to the present invention, and is a partially enlarged view of one end having conductors of the discharge lamp shown in FIG. In this embodiment, instead of using a metallic spring member or a magnetic material as the conductor,
A ring-shaped wire 18 is used. The embodiment using a ring-shaped wire as a conductor as introduced in this embodiment is particularly effective in a double-tube dielectric barrier discharge lamp in which an outer tube and an inner tube are coaxially arranged. That is, as shown in FIG.
Can be satisfactorily locked in the wire locking dent 19 provided in the inner tube 11, whereby the diameter of the ring-shaped wire 16 is larger than the sum of the outer diameter d 1 of the inner tube 11 and the discharge gap length d 2. If the relation is large, the wire 16 can contact both the inner tube 11 and the outer tube 12, and such a configuration can be assembled very easily. As an example of the ring-shaped wire, nickel, tungsten, platinum, stainless steel, or the like can be used. In addition, it may be a substantially C-shape having a cut part in a part instead of a complete ring shape, or an oval shape, a shape close to a square shape that is not a perfect circular shape, and furthermore, If the portion forming the arc has a spring property, the same operation and effect as the embodiment can be obtained. In the embodiment shown in FIG. 2, the conductor is held by the elastic force of the conductor itself, and in the embodiment shown in FIG. 4, the conductor is held by the magnetic force. However, the conductor in this embodiment is held by the gravity of the conductor itself. Will be.

FIG. 6 also shows another embodiment of the dielectric barrier discharge lamp of the present invention, which is a double tube type dielectric barrier discharge lamp similar to FIG. 5, and is a conductor of the discharge lamp shown in FIG. FIG. 4 shows a partially enlarged view of one end portion having the following. In this embodiment, for example, a platinum wire having a diameter of 0.4 mm is used as the conductor 16. The conductor 16 is wound around the inner tube 11,
One end is bent into a semicircle and is in contact with the inner surface of the outer tube 12. The platinum wire has no strong elastic force, but is in contact with the outer tube with a weak elastic force in the range of plastic deformation. However, if the holding force of this level is applied to the lamp, the conductor 16 moves when vibration or impact is applied to the lamp.
And a projection 21 for supporting the fixture 20 are provided and fixed. The fixture 20 may be a separate member from or integral with the conductor 16. The projections 21 may be, for example, perforated with small holes in a quartz glass plate, fixed through the fixture 20, and welded to the inner tube 11. In such a structure, the discharge phenomenon for the conductor 16 to generate a discharge base point is the same as that shown in the above-described embodiment. The feature of this structure is that conductor 1
6 is fixed in the discharge space by a conductor 16
Since there is no need to consider itself, the conductor 16 can be formed only in terms of the discharge starting point. Shape can be formed.

In the above embodiments, excimer light can be obtained even when the dielectric barrier discharge lamp is turned on, for example, from a commercial frequency of about 50 Hz to several MHz to several GHz or more.

Next, a light source device using the dielectric barrier discharge lamp of the present invention will be described. FIG. 7 shows the light source device 3
0, the metal block 31, the wall 32, and the light extraction window 33
Is formed in a box shape as a whole. The dielectric barrier discharge lamp 1 is arranged so as to fit into the concave portion of the metal block 31, and the radiated light is radiated through the light extraction window 33. The metal block 31 is provided with an optical sensor unit 35, which measures the amount of radiation and the like, and the cooling water pipe 3
6 is also provided. In addition, an inlet 34a and an outlet 35b for the inert gas are formed in the wall 32. The structure of such a light source device is general, and is disclosed in, for example, Japanese Patent No. 2836058, and a detailed description thereof will be omitted. In the light source device having such a structure, the dielectric barrier discharge lamp is provided with a conductor 16 provided in the discharge space.
Can be arranged so as to face the metal block 31. That is, the dielectric barrier discharge lamp emits ultraviolet light radially from the outer peripheral surface thereof. However, since ultraviolet light that goes straight to the light transmission window 33 has a low attenuation factor and a high use efficiency, such a light is used. This is because it may be advantageous not to dispose a conductor that causes light shielding in the direction.

The light transmission window 33 can be designed so as not to collide with the conductor 16 when a perpendicular line is drawn toward the dielectric barrier discharge lamp 1. Also in this case, it is effective to prevent the conductor 16 from being affected by partial light shielding. This is a preferable design particularly when it is desired to obtain uniform radiation from the light transmission window 33.

Next, experimental results showing the effects of the present invention will be described. The experiment was conducted on a dielectric barrier discharge lamp having the structure shown in FIG. 36m
m, the outer diameter of the inner tube 11 is 16 mm, the thickness of the inner tube 11 and the outer tube 12 is 2 mm, the discharge gap length is 8 mm, and xenon is filled as a discharge gas at 53 kPa. The experiment was performed using (between zero and peak). In the measurement, a lamp 1 in which nothing is disposed in the discharge space, a lamp 2 in which a quartz piece is disposed in the discharge space as a dielectric, a lamp 3 in which a conductor is disposed in the discharge space, and a plate spring shown in FIG. 3
For each type of dielectric barrier discharge lamp, the discharge starting voltage when the applied voltage was gradually increased was measured. The measurement was performed about 30 times for each lamp.

As a result, the lamp 1 has a discharge starting voltage of 7 to
8 KV (zero-peak voltage: the same applies hereinafter), lamp 2 had a discharge starting voltage of 4.5 to 5.5 KV, and lamp 3 was scattered in the range of 2.5 to 3.0 KV. This result not only indicates that the dielectric barrier discharge lamp of the present invention in which the conductor is disposed in the discharge space can start discharge by applying a remarkably low voltage, but also more surprisingly, the applied voltage is lower than the applied voltage at the time of steady lighting. That is, discharge can be started at a low voltage. This is a big change from the conventional wisdom. In this experiment, since the applied voltage at the time of steady lighting is 4 KV, it is necessary to apply this voltage in order to obtain a predetermined amount of radiation. However, as in a conventional dielectric barrier discharge lamp, it is necessary to apply this voltage. There is no need to apply a higher voltage than the voltage. This leads to a very large effect such as downsizing of the step-up transformer.

As another effect, in the above experiment, the lamps were started 30 times for each lamp, but the conventional lamps 1 and 2 had a variation of 1.0 kV. On the other hand, the lamp 3 of the present invention has a variation of 0.5 kV, and it can be seen that the dielectric barrier discharge lamp of the present invention can be reliably started to light at the set discharge starting voltage.

When dimming the dielectric barrier discharge lamp, there are generally a method of changing the amplitude of the applied high-frequency voltage and a method of changing the frequency of the applied high-frequency voltage. However, in the former case, the dimming range is limited in terms of the occurrence of unevenness in the emitted light, and even in the latter case, dimming cannot be satisfactorily performed due to the problem of saturation of the step-up transformer. As shown in FIG. 8, a method of periodically stopping the voltage supply to the lamp is also conceivable. In such a case, in the case of a conventional dielectric barrier discharge lamp, it is necessary to apply a high discharge starting voltage every time a voltage is applied as shown in FIG. It is necessary to take this into consideration, and a high load is applied to the dielectric barrier discharge lamp by applying a high voltage every time discharge is started. On the other hand, the dielectric barrier discharge lamp of the present invention can start discharge by applying the same or lower voltage as in normal lighting as described above, so that the above-described problem does not occur. Dimming of the discharge lamp can be performed by a lighting method that provides a regular pause.

[0031]

As described above, according to the present invention, it is possible to provide a dielectric barrier discharge lamp that can be reliably started by applying a low voltage.

[Brief description of the drawings]

FIG. 1 is a schematic view of a dielectric barrier discharge lamp of the present invention.

FIG. 2 is a partially enlarged view of the dielectric barrier discharge lamp of the present invention.

FIG. 3 is a partially enlarged view of the dielectric barrier discharge lamp of the present invention.

FIG. 4 is a partially enlarged view of the dielectric barrier discharge lamp of the present invention.

FIG. 5 is a partially enlarged view of the dielectric barrier discharge lamp of the present invention.

FIG. 6 is a partially enlarged view of the dielectric barrier discharge lamp of the present invention.

FIG. 7 is an example of a light source device using the dielectric barrier discharge lamp of the present invention.

FIG. 8 is a diagram for explaining the effect of the dielectric barrier discharge lamp of the present invention.

FIG. 9 is a diagram for explaining an effect of the dielectric barrier discharge lamp of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge container 11 Inner tube 12 Outer tube 13 Discharge space 14 Outer electrode 15 Inner electrode 16 Conductor 17 Conductor holding member

Claims (6)

[Claims] 1. A discharge vessel at least partially serving also as a dielectric of a dielectric barrier discharge, a discharge gas filled in the discharge vessel to form excimer molecules by the dielectric barrier discharge, and an outer surface of the discharge vessel. A dielectric barrier discharge lamp comprising a pair of electrodes arranged, wherein the discharge vessel has an electric conductor in contact with an inner surface portion of the vessel facing the electrodes. Discharge lamp. 2. The dielectric barrier discharge lamp according to claim 1, wherein said electric conductor is springy. 3. An electric conductor having a conductor holding member outside the discharge vessel, wherein at least one of the electric conductor and the conductor holding member has a magnetic force and the other is magnetized, so that the electric conductor is formed. 2. The dielectric barrier discharge lamp according to claim 1, wherein the dielectric barrier discharge lamp is held at a predetermined position in the discharge vessel. 4. The dielectric barrier discharge lamp according to claim 1, wherein the electric conductor is formed of small pieces, and is arranged at an angle of 90 ° or less with the inner surface of the discharge vessel. 5. The discharge vessel is of a generally double cylindrical type having an outer tube and an inner tube coaxially arranged, one of the electrodes being arranged on the outer surface of the outer tube and the other electrode being arranged on the outer surface of the inner tube. 2. The arrangement according to claim 1, wherein:
Dielectric barrier discharge lamp. 6. The electric conductor has a ring shape, the diameter of which is larger than the sum of the outer diameter of the inner tube of the discharge vessel and the discharge gap length, and the inner surface and the inner side of the outer tube of the discharge vessel. 6. The dielectric barrier discharge lamp according to claim 5, wherein the lamp contacts an inner surface of the tube.