JP2002164022A - Light emitting device and back light for plane display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device capable of exhibiting an excellent characteristic. SOLUTION: This light emitting device has a discharge vessel 1 having a discharge space 100 inside, and plural electrodes 40 arranged in the discharge space 100, covering the respective peripheries with a dielectric structure 30, and applied with alternating voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light emitting device and a backlight for a flat display, and more particularly to a light emitting device using a rare gas discharge and a backlight for a flat display.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of global environmental protection,
The use of harmful substances is being regulated or banned. One of the movements is mercury-free fluorescent lamps. Mercury plays an extremely important role in emitting ultraviolet light in fluorescent lamps and causing phosphors to emit light, while mercury has the danger of accumulating and causing harm in living organisms. At present, rare gases such as krypton and xenon are considered to be the most promising ultraviolet radiating materials in place of mercury. Among them, xenon is widely used as one having the highest excitation efficiency for emitting a fluorescent substance.

As shown in FIG. 18, xenon is excited by the collision of electrons or the like to form a resonance line level (8.45 e).
V), and 172 nm from excimer molecules generated from a metastable state (8.3 eV) via triple collisions. This 14
Various discharge modes have been studied in order to increase the radiation efficiency at 7 nm and 172 nm, but the highest radiation efficiency is currently reported using a dielectric barrier discharge.

[0004] The dielectric barrier discharge is a discharge performed through a dielectric, and has a feature that a large number of minute discharges are generated, and each minute discharge ends instantaneously. In the dielectric barrier discharge, since the discharge is instantaneously terminated, the electrons excited to the resonance line level are efficiently excited to 147 nm or 17 nm without being excited again to the upper high level band.
Emit 2 nm.

On the other hand, in discharges other than the dielectric barrier discharge,
Since the discharge does not end instantaneously and lasts for a long time, the electron density becomes excessive. As a result, the electrons excited to the resonance line level are again excited to the upper high level band as shown in FIG. 18, and then emit near-infrared light or visible light. Near-infrared light hardly contributes to the light emission of the phosphor, and visible light has extremely low luminous efficiency. Therefore, when such radiation is generated, the luminous efficiency is reduced.

Conventionally, light emitting devices using dielectric barrier discharge can be roughly classified into two types depending on the arrangement of electrodes. One is a surface discharge type light emitting device having a plurality of electrodes only on one of the substrates and causing a discharge on the surface (for example, see JP-A-6-223131 and JP-A-11-31480). ). The other has one or more electrodes on both substrates,
It is a light emitting device of a counter discharge type in which a discharge is generated between electrodes on a single substrate (for example, see JP-A-8-22805 and JP-A-8-287869). Each discharge type light emitting device will be described with reference to FIG. 16 and FIG.

FIG. 16 schematically shows a cross section of a surface discharge type light emitting device. The light emitting device shown is
Back substrate 11 (thickness 3) made of soda lime glass or the like
mm), a front substrate 21 (approximately 3 mm in thickness) provided opposite the rear substrate 11, and an outer frame 71 (the rear substrate 11 and the front substrate 21) located between the rear substrate 11 and the front substrate 21. (Discharge interval is 1 to 10 mm). A plurality of linear electrodes 4a (electrode width 0.2 to 2 mm, electrode interval 5 to 1)
5 mm), and a dielectric layer 130 made of glass or the like (having a thickness of 50 mm) so as to cover the linear electrodes 4a.
To 500 μm), and on the surface of the dielectric layer 130,
A light emitting layer 52 made of a phosphor or the like is formed. On the other hand, only the light emitting layer 52 is formed on the surface of the front substrate 21. The discharge vessel 3 includes a rear substrate 11 and a front substrate 21.
And the outer frame 71, and the rare gas 101 (for example, xenon) is 1 to 100 inside the discharge vessel 3.
It is sealed at a pressure of about kPa.

Next, the operation of the light emitting device shown in FIG. 16 will be described. First, when a sine wave or pulsed voltage of about 500 to 3000 V is applied to a plurality of adjacent linear electrodes 4a, the dielectric layer 130 is polarized, and an electric field is generated between the linear electrodes 4a. Then, when this electric field exceeds the electric field for starting the discharge of xenon, a minute discharge is started. At this time, electric charges are accumulated on the surface of the dielectric layer 130 by the minute discharge. When the combined electric field of the internal electric field due to the accumulated charges and the external electric field in the opposite direction due to the polarization of the dielectric layer 130 falls below the sustaining electric field, the micro discharge ends. The duration of the minute discharge is very short, and immediately after the end of the discharge, the next minute discharge is started in a place where the minute discharge has not yet occurred. By repeating the minute discharge, the discharge plasma 12a spreads uniformly. The discharge plasma 12a generated by the minute discharge is curved as shown in FIG. When the generation of these minute discharges ends, the discharge completely stops.

Next, a voltage in the opposite direction is applied to the linear electrode 4a, and the sum of the electric field generated by the charges accumulated on the surface of the dielectric layer 130 and the electric field generated between the gaps by the electrode applied voltage is the discharge starting voltage. Is exceeded, discharge starts again.
Thus, each time the application direction of the electrode application voltage changes, the start and the pause of the discharge are repeated. Discharge plasma 1
The ultraviolet light (not shown) emitted by 2 a is converted into visible light (not shown) by the light emitting layer 52 provided on the rear substrate 11 and the front substrate 21, and is guided out of the discharge vessel 3.

FIG. 17 schematically shows a cross section of a facing discharge type light emitting device. The illustrated light emitting device includes a back substrate 12 (thickness of about 3 mm) made of soda lime glass or the like, a front substrate 22 (thickness of about 3 mm) provided opposite to the back substrate 12, a back substrate 12 and a front substrate The discharge vessel 4 includes an outer frame 72 (the distance between the back substrate 12 and the front substrate 22 is 1 to 10 mm) positioned between the discharge container 4 and the outer frame 72. Electrodes 4b and 4c (electrode width 0.2 to 2 m) are provided on rear substrate 12 and front substrate 22.
m, and an electrode interval of 5 to 15 mm, respectively. The dielectric layer 131 (having a thickness of 50 to 5 mm) is formed on the rear substrate 12 and the front substrate 22 so as to cover the electrodes 4 b and 4 c.
00 μm), and a light emitting layer 53 is formed thereon. In this configuration, in order to reduce the electrode area so as not to block the visible light from the light emitting layer 53, for example, a stripe-shaped electrode is used as the electrode 4c on the front substrate 22, or indium tin oxide or the like is used. A transparent electrode has been used. The discharge vessel 4 is sealed by a back substrate 12, a front substrate 22, and an outer frame 72, similarly to the surface discharge type shown in FIG. 16, and inside the discharge vessel 4 is a rare gas 102 (for example, xenon). Is sealed at a pressure of about 1 to 100 kPa.

The operation of the light emitting device shown in FIG. 17 is basically the same as the operation of the light emitting device shown in FIG. The operation of the light emitting device shown in FIG. 17 will be briefly described. When a sine wave or pulsed voltage of about 500 to 3000 V is applied between the opposing electrodes 4b and 4c, a plurality of Discharge plasma 12b is generated. At that time, the ultraviolet light (not shown) emitted from the discharge plasma 12b is converted into visible light (not shown) by the light emitting layer 53 provided on the rear substrate 12 and the front substrate 22.
It is led out of the discharge vessel 4.

[0012]

The opposed discharge type light emitting device shown in FIG. 17 has three main problems as described below.

First, when aiming at a thin light emitting device such as a liquid crystal backlight, the distance between electrodes cannot be increased. Generally, it is empirically known that the light emission efficiency is reduced when the discharge gap is short. This is considered to be due to the low luminous efficiency near the electrodes. When a thin light-emitting device is configured by the opposed discharge type, the distance between the electrodes is short, that is, the discharge gap is short, so that the luminous efficiency is reduced. In addition, plasma
One reason that the luminous efficiency of the display panel does not increase from several lm / W is that the discharge gap is as short as several hundred micrometers.

Second, an electrode is formed on the light extraction surface. When light is desired to be extracted from the front surface of the light emitting device, when the electrode 4c formed on the front glass substrate 22 is made of a non-translucent material such as a metal,
Part of the light from the light emitting layer 53 is scattered or absorbed by the electrode 4c, and the luminance of the light emitting surface is reduced. In order to prevent a decrease in the luminance of the light emitting surface due to scattering or absorption of the electrode 4c, it is conceivable to reduce the electrode area. However, when the electrode area is reduced, the luminance is reduced and the resistance value of the electrode is increased. I will. For example, even if the electrode 4c is made of a translucent material, it is necessary to reduce the film thickness in order to increase the transmittance of the electrode, and the electrical resistance increases.

Third, the phosphor is greatly deteriorated. As can be understood from FIG. 17, the opposed discharge type light emitting device has a structure in which ions in the discharge plasma 12b directly collide with the light emitting layer 53 (phosphor layer). The collision of the ions with the phosphor deteriorates the phosphor and causes a significant decrease in luminance. This deterioration of the phosphor is the biggest problem of the opposed discharge type, and various studies have been made to solve this problem even in a DC type plasma display panel having a similar structure. .

Next, problems in the surface discharge type light emitting device shown in FIG. 16 will be described. First, the surface discharge type light emitting device can easily increase the discharge gap unlike the opposed discharge type light emitting device. However, since the starting voltage increases at the same time as the discharge gap increases, the discharge gap is suppressed within a range where the starting voltage does not become too high.

In a surface discharge type light emitting device,
Unlike the counter discharge type, all the electrodes 4a are provided on the back substrate 11, so that the light emission surface brightness does not decrease due to scattering or absorption of the electrodes. Since the electrodes are formed only on one of the substrates, damage to the phosphor can be halved. However, the biggest problem of the surface discharge type is, for example, Japanese Patent Application Laid-Open No. 2000-500916.
As described in the publication, the discharge plasma 12a is easily affected by the substrate surface.
This can be understood from FIG.
2a passes near the rear substrate 11. less than,
The influence of the discharge plasma 12a from the substrate surface will be described.

Some of the electrons and ions in the discharge plasma are:
The diffusion proceeds toward the substrate. In general, the speed of electrons is higher than the speed of ions, so that in a normal state, more electrons arrive at the substrate surface than ions. As a result, the electrons on the substrate surface form a negative electric field near the surface, and act to repel subsequent electrons. This negative electric field attracts ions while decelerating the electrons and eventually increases until the electron and ion currents reaching the surface are equal. Such a mechanism is called ambipolar diffusion (see:
"Plasma Basic Engineering", author: Nobutsu Tsutsui, publisher; In the case of the surface discharge type, if the distance between the discharge plasma and the substrate becomes small, the loss ratio due to recombination of electrons and ions on the substrate surface increases. Then, in order to maintain the conductivity of the discharge plasma, the number of re-supplied electrons and ions also increases, and the density of the electrons and ions in the discharge plasma increases. As described above, when the electron density becomes excessive, re-excitation of the xenon gas from the resonance line level becomes active, which causes a decrease in luminous efficiency (see FIG. 18). In addition, the increase in the electron density causes non-uniformity of the electric field intensity, and also becomes a factor of making the discharge unstable.

Furthermore, a problem common to both the opposed discharge type and the surface discharge type light emitting devices is that many high-temperature processes are required in the manufacturing process of the light emitting devices. When producing any type of light-emitting device, a total of 5 times, including electrode formation, dielectric layer formation, light-emitting layer formation, sealing and exhaustion, up to 60 times
A high-temperature process near 0 ° C. was required, and in order to withstand these high temperatures, it was necessary to use a glass substrate having a small thermal distortion and a large thickness.

The present invention has been made in view of the above points, and a main object thereof is to provide a light emitting device having characteristics superior to those of the prior art.

[0021]

According to the present invention, there is provided a light emitting device comprising: a discharge vessel having a discharge space therein; and a discharge vessel provided in the discharge space. And a plurality of electrodes to which is applied.

It is preferable that a part of the dielectric structure other than a part supported by the discharge vessel is separated from the discharge vessel.

In one embodiment, the dielectric structure is a glass tube, and each of the plurality of electrodes is arranged in the glass tube so as not to be exposed to the discharge space, and the discharge vessel It has been extended outside.

It is preferable that each of the plurality of electrodes has a hollow structure.

[0025] Each of the plurality of electrodes may have a mesh-like structure. Each of the plurality of electrodes may have a structure separated in a longitudinal direction.

It is preferable that at least a part of the discharge vessel has a translucent portion, and at least a part of an inner surface of the discharge vessel is provided with a light emitting layer.

In one embodiment, the discharge vessel comprises a front substrate and a rear substrate opposed to each other, and the plurality of electrodes are arranged at regular intervals, and are arranged at equal intervals. And are arranged in a plane so as to be parallel to.

Preferably, the discharge vessel is provided with a groove for accommodating a part of the dielectric structure and supporting the dielectric structure.

Preferably, the plurality of electrodes are arranged such that electrodes connected to the high voltage side of the power supply and electrodes connected to the ground side alternate.

In one embodiment, the electrodes including the dielectric structures in contact with each other, the electrodes of which are surrounded by the dielectric structures in contact with each other, are brought to the same potential and brought to the same potential. The electrode comprises an electrode connected to the high voltage side of the power supply or an electrode connected to the ground side.

Preferably, the area of the electrodes located at both ends of the plurality of electrodes is half the area of the electrodes located at positions other than the both ends.

In one embodiment, each of the plurality of electrodes is covered by one dielectric structure, and the areas of the electrodes located at positions other than both ends are substantially equal.

In one embodiment, the electrodes located at both ends are electrodes whose periphery is covered by one dielectric structure, and the electrodes located at positions other than the two ends are two electrodes in contact with each other. It is composed of two electrodes whose periphery is covered by a body structure, and the sum of the electrode areas of the two electrodes is twice the area of the electrodes located at both ends.

It is preferable that at least a part of the surface of each of the plurality of electrodes is in close contact with the dielectric structure.

The backlight for a flat display according to the present invention has a discharge space inside, and a discharge vessel in which at least a rare gas is filled as a luminescent substance in the discharge space, and a portion other than a portion supported by the discharge vessel. A portion provided in the discharge space apart from the discharge vessel;
A plurality of tubes made of a dielectric, and provided inside each of the plurality of tubes, an electrode to which an alternating voltage is applied,
The discharge vessel is composed of a front substrate and a rear substrate facing each other, the plurality of tubes are arranged in a plane so as to be parallel to the front substrate or the rear substrate, and At least a part is provided with a translucent part, and at least a part of the inner surface of the discharge vessel is provided with a light emitting layer.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor of the present application has searched for the possibility of a new type of light emitting device which can solve the problems of the conventional opposed discharge type and surface discharge type light emitting devices, and has conducted extensive research. And completed such a new type of light emitting device. In other words, the problems of the conventional opposed discharge type in which the distance between the electrodes cannot be increased, the point that the electrode is formed on the light extraction surface, and the fact that the phosphor is greatly deteriorated are solved. A new type of light emitting device that solves the problem that plasma is easily affected by the substrate surface has been realized.

A light emitting device according to the present invention has a plurality of electrodes provided in a discharge space inside a discharge vessel, each of the electrodes being covered by a dielectric structure. That is, unlike any type of configuration of the prior art,
The electrode is provided in the discharge space, and has a configuration in which a dielectric is formed around the electrode. Since the electrodes are provided in the discharge space, there is no need to form electrodes on the light extraction surface, and the distance between the electrodes can be set arbitrarily without depending on the size of the substrate and the distance between the substrates. Can reduce the influence on the discharge plasma. In addition, since the discharge may be performed between the electrodes provided in the discharge space, the problem of deterioration of the phosphor can be avoided. In addition, since the periphery of the electrode is covered with the dielectric structure, a dielectric barrier discharge that can obtain high luminous efficiency can be performed, and the electrode is not exposed in the discharge space. it can.

By arranging the dielectric structure so as to be separated from the discharge vessel except for the support portion with the discharge vessel, it is possible to more effectively reduce the influence of the discharge vessel (substrate). For example, a glass tube may be used as the dielectric structure, and an electrode (for example, a linear electrode made of Al) may be arranged in the glass tube. If an electrode having a hollow structure or a mesh-like structure is used, destruction and cracking caused by a difference in the thermal expansion coefficient between the electrode and a dielectric structure (for example, a glass tube) can be effectively prevented. Can be.

In the case of a light emitting device using a rare gas,
At least a rare gas as a light-emitting substance may be sealed in the discharge space, and a light-transmitting portion is provided on at least a part of the discharge vessel, and a light-emitting layer is provided on at least a part of the inner surface of the discharge vessel. Ultraviolet light can be extracted to the outside as visible light. If mercury is not sealed in the discharge vessel, a preferable light emitting device can be provided from the viewpoint of global environmental protection.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments. Embodiment 1 A light emitting device according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 (a) and 1 (b) and FIG. FIG. 1A schematically shows a vertical cross section of the light emitting device of the present embodiment.
(B) schematically shows a horizontal cross section of the light emitting device of the present embodiment. FIG. 2 schematically shows a configuration of an outer frame included in the light emitting device of the present embodiment.

The light emitting device shown in FIGS. 1A and 1B has a discharge vessel 1 having a discharge space 100 therein,
It has a plurality of electrodes 40 provided in the discharge space 100 and each of which is surrounded by a dielectric structure 30. An alternating voltage is applied to the plurality of electrodes 40. In the present embodiment, the discharge vessel 1 includes a front substrate 20 and a rear substrate 10 facing each other, and a space sandwiched between the front substrate 20 and the rear substrate 10 is a discharge space 100. The thicknesses of the front substrate 20 and the rear substrate 10 are, for example, 2.8 mm and 2.8 mm, respectively, and the distance between the substrates is 4.8 mm. A rare gas (for example, xenon) serving as a light emitting substance is sealed in the discharge space 100, and when the light emitting device is turned on,
Noble gas discharge plasma 120 is generated between the electrodes 40. In the present embodiment, xenon is filled at 13.3 kPa as a light emitting substance.

The front substrate 20 and the rear substrate 10 are each made of translucent soda lime glass, and the phosphor (on the inner surface of the discharge vessel 1) is formed on each of the front substrate 20 and the rear substrate 10. Light emitting layer 50 is formed. Since the light emitting layer 50 is provided on the inner surface of the discharge vessel 1, the ultraviolet light emitted from the discharge plasma 120 can be converted into visible light and extracted. As the phosphor constituting the light emitting layer 50, for example, a phosphor for a plasma display panel can be used.

Between the front substrate 20 and the rear substrate 10,
A spacer 6 for defining the distance between the substrates is provided, and a rectangular outer frame 70 is arranged around the rear substrate 10 located outside the spacer 6. As shown in FIG. 2, the outer frame 70 is formed with a groove (in FIG.
U-shaped grooves) are provided, and using these grooves,
The dielectric structure 30 including the electrode 40 therein can be housed and supported. In the present embodiment, the grooves for the dielectric structure 30 are provided at the same height and the same size and at equal intervals. An exhaust pipe 9 for introducing a luminescent substance such as a rare gas into the discharge space 100 is provided on a side surface of the discharge vessel 1, and the dielectric frame 3 is provided on the outer frame 70.
A groove for passing the exhaust pipe 9 is formed along with a groove for passing the exhaust pipe 9. Outer frame 70, front substrate 20 and rear substrate 1
0 indicates that the discharge space 100 is sealed by the low-melting glass 8. Note that an opening (through hole) may be provided in the outer frame 70 instead of the groove.

Each of the plurality of electrodes 40 provided in the discharge space 100 is disposed inside the dielectric structure 30 so as not to be exposed to the discharge space 100, and extends to the outside of the discharge vessel 1. ing. Each of the plurality of electrodes 40 in the present embodiment has a structure in which the inside is hollow. The electrode structure having a hollow inside can be realized by a configuration in which an aluminum foil is cylindrical. When the light emitting device is turned on, a crack (destruction) of the dielectric structure 30 caused by a difference in the coefficient of thermal expansion (coefficient of thermal expansion) between the electrode 40 and the dielectric structure 30 can be obtained by using an electrode structure having a hollow inside.・ Cracks) can be prevented.

When a crack occurs in the dielectric structure 30, the sealed rare gas leaks and the discharge vessel 1
Cannot be lit. Generally, the coefficient of thermal expansion of the electrode 40 is larger than the coefficient of thermal expansion of the dielectric 30. Therefore, when the temperature of the electrode 40 rises during lighting, a large stress is applied to the dielectric structure 30, which causes cracks. . When the inside of the electrode 40 is hollow, the stress on the dielectric structure 30 can be minimized, and the durability of the discharge vessel 1 can be improved. Further, as shown in FIG. 3, the same effect can be obtained even when the electrode 40 has a mesh structure. The electrode 4
The same effect can be obtained even if the inside of 0 or the gap of the mesh is filled with an insulator having a lower coefficient of thermal expansion than metal.

It should be noted that, in the present embodiment, in order to prevent stress from being applied to the dielectric structure 30 at the time of manufacturing the light emitting device, 1
One dielectric structure 30 supports one of the dielectric structures 30 (one end). That is, in the case where the dielectric structure 30 is supported at both ends, the dielectric structure 30 is fixed to the discharge vessel 1 when the dielectric structure 30 is thermally expanded in the manufacturing process of the light emitting device, so that the dielectric structure 30 returns to room temperature. Then, the dielectric structure 30 receives tensile stress from both ends, and is supported at one end so that such stress is not applied. However, by selecting a material constituting the dielectric structure 30, the dielectric structure 3
In the case of a configuration in which stress is not so much applied to zero, one dielectric structure 30 may be supported at two places (both ends).

The plurality of electrodes 40 in the discharge space 100 are arranged at equal intervals, and are arranged in a plane so as to be parallel to the front substrate 20 or the rear substrate 10. With this arrangement, the electric field strength between the electrodes 40 can be made constant, and the distance between the electrodes 40 and the front substrate 20 or the rear substrate 10 can be made constant, so that the distribution of the electron density between the electrodes can be improved. Can be made constant, and as a result, a more uniform light emitting surface can be obtained. Further, by arranging the plurality of electrodes 40 in a planar shape, a thin light-emitting device can be obtained, which can be suitably used as a backlight of a flat display such as a liquid crystal display device (liquid crystal display panel). In addition, when each of the plurality of electrodes 40 is arranged in a planar shape, the shade of the electrodes 40 is more likely to appear as compared with a case where each of the plurality of electrodes 40 is arranged, for example, at a step.
Actually, since light is scattered by the light emitting layer 50, light in a state where the influence of the shadow of the electrode 40 is reduced is extracted from the discharge vessel 1.

The dielectric structure 30 covering the periphery of the electrode 40
Has an elongated shape and is, for example, a tube made of a dielectric material. In the present embodiment, as the dielectric structure 30,
A glass tube (for example, an outer diameter of 2.8 mm and an inner diameter of 1.6 mm) made of soda lime glass is used. A portion of the glass tube (dielectric structure) 30 other than a portion supported by the discharge vessel 1 (for example, a groove of the outer frame 70) (for example, a portion where the outer periphery of the glass tube is exposed to the discharge space 100). Are provided in the discharge space 100 at a distance from the discharge vessel 1. The length of the portion where the outer periphery of the glass tube is exposed to the discharge space 100 is, for example, about 50 mm.
Similarly to the electrode 40, the glass tubes 30 are arranged such that the tubes are arranged at equal intervals, and are arranged in a plane so as to be parallel to the front substrate 20 or the rear substrate 10.
In the present embodiment, the interval between the glass tubes 30 is 10 mm, and the interval between the glass tubes 30 and the front substrate 20 is, for example, 1 mm.
mm, and the distance between the glass tube 30 and the back substrate 10 is 1 mm. Further, in the present embodiment, in order to prevent unnecessary discharge (for example, discharge such as generation of ozone) from occurring due to the presence of air between the electrode 40 and the glass tube (dielectric structure) 30, The outer surface of the hollow electrode (cylindrical aluminum electrode) 40 is adhered to the inner surface of the glass tube 30 without any gap.

Each of the electrodes 40 is connected to a lighting power supply 110 at a portion extending to the outside of the discharge vessel 1.
One electrode 40 formed in one glass tube 30 is
The same potential (for example, either the high voltage potential or the ground potential) is set. As shown in FIG. 1A, in the present embodiment, in order to generate a discharge plasma 120 over the entire substrate and obtain a uniform light emitting surface, each electrode 40 is connected to the high voltage side of the lighting power supply 110. The lighting power supply 110 is electrically connected so that the ground side and the ground side alternate. For example, a frequency of 30 kHz is applied from the lighting power supply 110 to each electrode 40.
z, a pulse width of 10 μsec and an AC pulse of 2000 Vo-p are applied.

In the present embodiment, as shown in FIG. 1, the area of the electrodes located at both ends of the plurality of electrodes 40 is set to half the area of the electrodes located at the other ends (the electrodes located at the center). ing. In the configuration of the present embodiment, the electrode 4
In other words, the contact area of the electrodes 40 provided in the glass tubes 30 located on both sides with the glass tubes 30 of the other electrodes 40 in order to bring the outer surface of the glass tube 30 into close contact with the inner surface of the glass tube 30. And half of the contact area.
With such a configuration, discharge can be performed between all of the plurality of electrodes 40, and a more uniform light emitting surface can be obtained. The inventor of the present application has experimentally confirmed that a discharge can occur between all the electrodes when the electrode area at both ends is reduced to half. This is described further below.

First, the inventor of the present application has experimentally confirmed that in the case of a configuration in which the electrode areas of the plurality of electrodes 40 are all the same, discharge easily occurs between the pair of electrodes. That is,
When the electrode areas of all the electrodes are equal, in the configuration shown in FIG. 1, the first, second, third and fourth from the left in the figure
Discharge is likely to occur between the fifth, sixth, and fifth electrodes, but no or only weak discharge occurs between the second, third, fourth, and fifth electrodes from the left.

On the other hand, in the case of a configuration in which the electrode areas at both ends are halved, good results are obtained between all the electrodes, that is, between any of the first to sixth adjacent electrodes from the left in the drawing. It was confirmed experimentally that discharge was possible. The reason for this is that if the electrode area at both ends is halved, each electrode discharges with respect to the adjacent electrode with an electrode area (S / 2) that is half the area (S) of the central electrode. To be able to do that.
On the other hand, when the electrode areas of the electrodes 40 are all the same,
It is inferred that performing a discharge with an electrode area S between a pair of electrodes results in a more stable discharge than discharging between all the electrodes.

Next, the operation of the light emitting device according to this embodiment will be described.

First, when an alternating voltage (for example, an AC pulse voltage) is applied to a plurality of electrodes 40 each electrically connected to either the high voltage side or the ground side of the lighting power supply 110, the glass tube 30 is constructed. The resulting dielectric is polarized, and an electric field is generated between the plurality of electrodes 40. When this electric field exceeds the electric discharge starting electric field of the enclosed xenon gas, a minute electric discharge is started. At this time, electric charges are accumulated on the surface of the dielectric by the minute discharge. When the combined electric field of the internal electric field due to the accumulated charges and the external electric field in the opposite direction due to the polarization of the dielectric falls below the sustaining electric field, the minute discharge ends.

Since the duration of the minute discharge is very short, immediately after the end of the discharge, the next minute discharge is started in a place where the minute discharge has not yet occurred. By repeating the minute discharge, the discharge plasma 120 spreads uniformly among the plurality of electrodes 40. It has been confirmed by the present inventors that the discharge plasma 120 spreads uniformly. When the generation of the minute discharge ends, the discharge is completely stopped.

Next, a reverse voltage is applied to the plurality of electrodes 40, and the sum of the electric field generated by the charges accumulated on the surface of the dielectric 30 and the electric field generated between the electrodes 40 due to the electrode applied voltage becomes When the voltage exceeds the discharge starting voltage, the discharge starts again.
Thus, each time the application direction of the electrode application voltage changes, the start and the pause of the discharge are repeated.

The ultraviolet light emitted from the discharge plasma 120 is converted into visible light by the light emitting layer 50 on the back substrate 10 and the front substrate 20, and this visible light is guided out of the discharge vessel 1. By such an operation, the light emitting device of the present embodiment exhibits a luminance of 10,000 (cd / m ² ) or more,
A very high brightness, high efficiency and uniform white light emitting surface is realized.

The reason why the alternating voltage is applied to the electrode 40 to turn on the light emitting device in this embodiment will be described with reference to FIG.

As shown in FIG. 4A, when an alternating voltage is applied between the electrodes 40, a uniform discharge plasma 120 can be generated between the electrodes 40. Further, in the light emitting device of the present embodiment, since all the electrodes 40 are covered by the dielectric structure (glass tube) 30,
All the electrodes 40 can be protected from ions at the time of discharge, and the life of the electrodes 40 can be extended.

On the other hand, as shown in FIG. 4B, when the light emitting device is turned on by direct current (DC) instead of alternating voltage, the following problem occurs. In the case of lighting with direct current (for example, in the case of unipolar pulse lighting), since the discharge column (discharge plasma) 120 spreads in a fan shape from the cathode 40 'to the anode 40, the discharge column near the cathode 40' becomes sparse. As a result, the luminance of the light emitting layer near the cathode is reduced. That is, as compared with the case of the alternating voltage, the luminance unevenness increases. In addition, when lighting with direct current, FIG.
The cathode can be configured as the bare electrode 40 'as in the configuration shown in (b). However, in such a configuration, ions directly collide with the bare electrode 40' during discharge, so that The electrode is sputtered, resulting in a shortened life of the electrode. In addition, since unevenness is formed on the electrode by sputtering, non-uniformity of discharge is increased. Further, there is a problem that the scattered electrodes adhere to the surface of the light emitting layer. If the lighting is performed at the alternating voltage in the configuration shown in FIG. 1, such a problem can be avoided.

In the light emitting device of the present embodiment, since the plurality of electrodes 40 each covered by the dielectric structure 30 are provided in the discharge space 100, unlike the prior art, the electrodes are formed on the light extraction surface. No need. As a result, a high-luminance and uniform light-emitting surface can be obtained. Also,
Since the dielectric structure 30 has an elongated shape, it is possible to minimize the influence that the light emission from the light emitting layer 50 on the rear substrate 10 is blocked by the dielectric 30.

Further, the plurality of electrodes 40 are connected to the discharge space 100.
Since it is provided inside, the distance between the electrodes 40 can be increased without depending on the size of the front substrate 20 and the rear substrate 10 and the distance between the substrates, as long as the starting voltage does not become too high. Further, since the plurality of electrodes 40 are provided in the discharge space 100, the discharge plasma 120 is applied to the front substrate 2.
0 and the back substrate 10, and an excessive increase in electron density can be suppressed. As a result, stable discharge with high luminous efficiency can be obtained. In addition, the ions in the discharge plasma 120 are emitted by the light emitting layer 50 (phosphor layer).
Since there is no direct collision, the phosphor of the light emitting layer 50 can be hardly deteriorated, and as a result, high luminance can be maintained for a long time.

As described above, according to the present embodiment, it is possible to provide a light emitting device exhibiting characteristics superior to those of the prior art.

When the light emitting device of the present embodiment is used as a backlight for a large-screen flat display, as shown in FIG. The electrode 40 may be extended so as to be positioned in the discharge space 100.
The configuration in which the glass tube 30 is extended from both sides of the outer frame 70 to support one end of the glass tube 30 is longer than the configuration in which the long glass tube 30 is extended from one side of the outer frame 70 to support one end of the glass tube 30. This is because the stress applied to the glass tube 30 at the support portion of the outer frame 70 can be reduced.
That is, if two glass tubes 30 each having a half length are used instead of one long glass tube 30, the stress applied to the supporting portion by the weight of the glass tube 30 can be greatly reduced. As a result, the possibility that the glass tube 30 is broken can be reduced.

Further, by modifying the configuration shown in FIG. 5, as shown in FIG. 6, the electrode 40 on the high voltage side may be extended from one side, and the electrode 40 on the ground side may be extended from the other side. Good. By doing so, in addition to the effect of the configuration shown in FIG. 5, the wiring between the electrode 40 and the lighting power supply 110 can be simplified. Since the wires having different polarities are arranged apart from each other, it is possible to prevent a current from leaking.

In the structure shown in FIGS. 1, 5 and 6, the glass tube 3 located in the discharge space 100
For example, a base (not shown) for supporting the front end is provided below the front end of the glass tube 30, and the front end of the glass tube 30 is supported by the base.
A configuration may be employed in which the stress applied to the support of the glass tube 30 is reduced. If the tip of the glass tube 30 and the base are not fixed, even if heat shrinkage occurs in the glass tube 30 during the manufacturing process, it is possible to prevent the glass tube 30 from being subjected to tensile stress. Can be prevented from being damaged.

Next, a method for manufacturing the light emitting device according to this embodiment will be described.

First, a back substrate 10 (2.8 mm thick) made of translucent soda lime glass and a front substrate 20
After preparing (a thickness of 2.8 mm), the light emitting layer 50 is formed on the rear substrate 10 and the front substrate 20. The light emitting layer 50 may be formed as follows.

First, phosphors for a RGB three-color plasma display panel are sufficiently dispersed in a vehicle (eg, α-terpineol + 25 wt% acrylic resin) as a dispersion medium. As a phosphor for a plasma display panel of three colors of RGB, for example, 5
Europium-activated yttrium gadolinium borate phosphor having a center wavelength of light emission at around 90 nm, 610 nm, and 630 nm, a magnesium-activated aluminate phosphor having a center wavelength of light emission at around 515 nm, and having a center wavelength of light emission near 455 nm A europium-activated barium magnesium aluminate phosphor can be used. Next, the phosphor dispersed in the vehicle is printed on the substrate by screen printing to form a uniform phosphor layer.
Next, this layer is sufficiently dried, and then heated and fired at an atmosphere temperature of 450 ° C., whereby the vehicle is fired and scattered to obtain the light emitting layer 50 fixed to the surfaces of the back substrate 10 and the front substrate 20. .

Next, in order to determine the distance between the substrates,
For example, as shown in FIG. 1B, a spacer 6 made of soda lime glass and having a thickness of 4.8 mm is arranged around the periphery of the back substrate 10, and a rectangular outer frame 70 (long side length 90 mm, The short side length is 64 mm and the height is 3.8 mm). The outer frame 70 is made of soda lime glass. As shown in FIG. 2, the outer frame 70 has a U-shape through which the dielectric structure (glass tube) 30 and the exhaust pipe 9 pass. A plurality of grooves are provided. The plurality of grooves for the dielectric structure 30 have the same height, the same size, and are provided at equal intervals.

Next, for example, a plurality of tubular dielectric structures (glass tubes) 30 made of soda lime glass or the like and having an outer diameter of 2.8 mm and an inner diameter of 1.6 mm, and an exhaust pipe 9 also made of soda lime glass or the like Are arranged in predetermined grooves of the outer frame 70, respectively. The interval between the plurality of dielectrics 30 is, for example, 10 mm, and the length of the glass tube 30 in the portion located in the discharge vessel 1 is, for example, 50 mm.

Next, a low-melting glass paste was prepared from a low-melting glass 8 (for example, manufactured by Asahi Glass Co., Ltd.) as a sealing material and a resin dispersion medium (for example, vehicle C manufactured by Tokyo Ohka Kogyo Co., Ltd.). Thereafter, the low-melting glass paste is uniformly discharged onto the upper portion of the outer frame 70 by a dispenser or the like, and further discharged so as to fill the grooves of the outer frame 70 in which the dielectric 30 and the exhaust pipe 9 are arranged. Next, the discharging and drying are repeated until the total height of the thickness of the low-melting glass paste and the height of the back substrate 10 becomes higher than the height of the spacer 6 by about several mm. Thereafter, the low-melting glass paste is discharged and dried along the outer portion where the outer frame 70 and the rear substrate 10 are in contact. Next, the outer frame 7
And the front substrate 20 on which the light emitting layer 50 is formed, and then firmly fixed with a heat-resistant metal fitting. Next, this is heated and baked at an atmosphere temperature of 450 ° C. to melt the lead glass powder in the low-melting glass paste, and sinter and scatter the resin dispersion medium. In this manner, the low-melting glass 8 seals the rear substrate 10 and the front substrate 20 at the interval of the thickness of the spacer 6. Through the above steps, the rear substrate 10, the front substrate 20, and the outer frame 70 are integrally fixed, and the discharge vessel 1 is obtained.

Next, the exhaust pipe 9 is connected to a vacuum pump (not shown), and the impurity gas in the discharge vessel 1 is exhausted in an atmosphere of 350 ° C. Next, after returning the atmosphere to room temperature, a rare gas composed of, for example, xenon alone is filled at 13.3 kPa. Thereafter, the exhaust pipe 9 is sealed using a burner or the like,
Remove unnecessary parts.

Next, the electrode 40 made of, for example, aluminum foil is formed into a cylindrical shape, and the cylindrical electrode is connected to the dielectric structure 30.
Adheres to the inside surface of the body without gaps. At this time, the electrodes 40 are bonded to the inner surfaces of the dielectrics 30 located on both sides of the plurality of dielectric structures 30 only in half in the direction in which the dielectric structures 30 are arranged next to each other. Thus, the light emitting device according to the present embodiment is obtained.

Each of the electrodes 40 of the obtained light emitting device is connected alternately to the high voltage side and the ground side of the lighting power supply 110, for example, at a frequency of 30 kHz, a pulse width of 10 μsec, and a voltage of 20 μm.
The light emitting device can be lit by applying a 00V-p AC pulse from the lighting power supply 110 to each electrode 40.

In the manufacturing method according to the present embodiment, since only the high-temperature process of a maximum of 450 ° C. needs to be performed three times, that is, formation of the light-emitting layer, sealing, and evacuation, the manufacturing process can be performed in comparison with the prior art. In addition to being able to greatly simplify, the use of thick glass substrates is no longer required. Further, thermal distortion of the back substrate 10 and the front substrate 20 can be suppressed. Further, in the manufacturing process of the present embodiment, the electrode 40 can be provided after the rare gas is sealed in the discharge vessel 1, that is, after the thermal process is completed. Therefore, the electrode 40 is not oxidized by heat, and therefore, And an electrode having a low resistivity. Embodiment 2 A light emitting device according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 7 schematically illustrates a cross-sectional structure (a cross-sectional structure in a direction perpendicular to the back substrate 10) of the plurality of electrodes 41 in the light emitting device according to the present embodiment.

The light emitting device according to the present embodiment is different from the light emitting device according to the first embodiment in that the light emitting device has electrodes 41 separated into two or more along the longitudinal direction of the dielectric structure (glass tube) 31. Different from light emitting devices. In the configuration shown in FIG. 7, the dielectric structure 31 has the same structure as the dielectric structure 30 of the first embodiment, and the discharge plasma 121 is the discharge plasma 12 of the first embodiment.
Occurs by a mechanism similar to zero. In the present embodiment and the embodiments described later, in order to simplify the description, the points different from the first embodiment will be mainly described, and the description of the same points as the first embodiment will be omitted or simplified.

As shown in FIG. 7, the electrode 41 in the present embodiment has a structure separated into two or more along the longitudinal direction of the dielectric structure (glass tube) 31. The electrode 41 shown in FIG. 7 has a structure in which the upper part and the lower part of the electrode 40 of the first embodiment are chipped, and has two parts (left part and right part) extending along the axial direction of the glass tube 31. Portion), and the two portions are opposed to the two portions of the electrode 41 located in the adjacent glass tube 31. That is, two portions of each of the plurality of electrodes 41 are arranged in a direction parallel to the rear substrate 10 (or the front substrate 20). The distance between the left and right portions (upper and lower gaps) of the electrode 41 is, for example, about 1.5 mm. Note that, similarly to the electrode 40 of the first embodiment, the outer surfaces of the left and right portions of the electrode 41 are
1 is in close contact with the inner surface.

The light emitting device of this embodiment has the electrodes 41 having the structure shown in FIG.
From both sides, a uniform discharge plasma 121 can be generated, and the progress of visible light in the vertical direction of the substrate can be prevented from being hindered by the electrode 41. Can be held down. For such a reason, a light emitting surface with an extremely high degree of uniformity can be obtained.

In addition to the above effects, it is needless to say that the same effects as in the first embodiment can be obtained. Third Embodiment A light emitting device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 8 schematically illustrates a cross-sectional structure (a cross-sectional structure in a direction perpendicular to the back substrate 10) of the plurality of dielectric structures 32 in the light-emitting device according to the present embodiment. Note that the dielectric structures 32 near both ends are shown, and other dielectric structures are omitted.

The light emitting device according to the present embodiment is different from the light emitting device of the first embodiment in that the dielectric structures 32 located at the center other than both ends are in contact with each other. In the configuration shown in FIG. 8, the dielectric structure 32 and the electrode 42 have the same structure as the dielectric structure 30 and the electrode 40 of the first embodiment, and the discharge plasma 122 is It is generated by the same mechanism as that of the first discharge plasma 120.

As shown in FIG. 8, the light emitting device according to the present embodiment has a configuration in which dielectric structures 32 located at the center other than both ends are in contact with each other in the direction parallel to the substrate. In other words, the electrodes 42 located at both ends are provided within one dielectric structure 32, and the electrodes 42 located at the center are placed inside the two dielectric structures 32 in contact with each other. 42 are provided one by one. Since the two electrodes in the center are a pair,
The sum of the electrode areas of the electrodes (two electrodes) located at the center is twice as large as the electrode areas of the electrodes located at both ends. The two dielectric structures 32 do not necessarily need to be in close contact with each other, but may be in light contact with each other, or may have a slight gap.

The electrode 42 is electrically connected to the lighting power supply 111 so that the pair of electrodes at the central portion have the same potential, and the electrode 42 or the adjacent electrode 42 or The lighting power supply 111 and the electrode 42 are electrically connected so that the opposite potential is applied to the pair of electrodes 42. That is, the electrodes connected to the high voltage side of the power supply and the electrodes connected to the ground side are arranged alternately. The inner surface of the dielectric structure 32 and the electrode 42
The area of contact with is set equal in all dielectric structures 32.

Since the light emitting device of this embodiment has a configuration in which the dielectric structures 32 located at the center other than both ends are in contact with each other, the electrodes (a set of two electrodes) 42 located at the central portion are provided. Of the electrode 4 located at both ends
2 is twice as large as the electrode area. Therefore, in a configuration using the dielectric structure 32 having the same contact area between the inner surface of the dielectric structure 32 and the electrode 42, the discharge plasma 122 is generated between all the electrodes as in the first embodiment. be able to. As a result, a more uniform light emitting surface can be obtained.

Since the light emitting device of this embodiment can use the dielectric structure 32 and the electrode 42 having the same structure, the discharge plasma 122 is generated between all the electrodes as compared with the light emitting device of the first embodiment. A light emitting device that can be manufactured can be easily manufactured. In the present embodiment, the two dielectric structures 32 are in close contact with each other in a direction parallel to the substrate. However, the two dielectric structures 32 may be in close contact with each other in a direction perpendicular to the substrate. Since the sum of the electrode areas of the electrodes 42 located at the central portion can be twice as large as the electrode areas of the electrodes 42 located at both ends, the same effect can be obtained.

In addition to the above effects, it is needless to say that the same effects as in the first embodiment can be obtained. Embodiment 4 Next, a light emitting device according to Embodiment 4 of the present invention will be described. The light emitting device according to the present embodiment is characterized in that at least a part of the outer surface of the dielectric structure 30 of the light emitting device according to the first embodiment is coated with a material (for example, magnesium oxide) that reflects visible light. In this embodiment, the light emitting device is different from the light emitting device of the first embodiment. The other points are the same as in the first embodiment, and a description thereof will not be repeated.

For coating the surface of the dielectric structure with magnesium oxide, for example, the following method may be used.
First, butyl acetate as a dispersion medium and ethyl cellulose as a binder are added to the fine particles of magnesium oxide, and then the mixture is sufficiently stirred, and then the mixture is applied to the surface of the dielectric structure. Next, after sufficiently drying the applied mixture, it is dried for 45 minutes.
When the dispersion medium and the binder are fired and scattered by firing at 0 to 550 ° C., magnesium oxide fixed to the dielectric surface is obtained.

In the present embodiment, at least a portion of the outer surface of the dielectric structure has a material (for example,
Since it is coated with magnesium oxide, visible light emitted from the light emitting layer 50 is guided to the outside of the substrate without being absorbed by the dielectric structure. As a result, higher luminance can be realized.

In addition to the above effects, it is needless to say that the same effects as in the first embodiment can be obtained. Embodiment 5 Next, a light emitting device according to Embodiment 5 of the present invention will be described. The light emitting device according to the present embodiment is different from the light emitting device according to the first embodiment in that at least a part of the outer surface of the dielectric structure 30 of the light emitting device is coated with a material that reflects ultraviolet light (for example, aluminum oxide). This is different from the light emitting device of the first embodiment. The other points are the same as in the first embodiment, and a description thereof will not be repeated.

To coat the surface of the dielectric structure with aluminum oxide, for example, fine particles of aluminum oxide may be used instead of the fine particles of magnesium oxide used in the fourth embodiment.

In the present embodiment, at least a portion of the outer surface of the dielectric structure is coated with a material that reflects ultraviolet light, so that the ultraviolet light generated by the discharge of the sealing gas hardly affects the dielectric structure. Without being absorbed, it reaches the light emitting layer and is converted to visible light,
Further higher luminance can be realized. In addition to the above effects, it is needless to say that the same effects as in the first embodiment can be obtained.

It is also possible to combine the visible light reflecting material and the ultraviolet light reflecting material in Embodiments 4 and 5 described above. Any place on the dielectric surface, such as when each of the visible light reflecting material and the ultraviolet light reflecting material is provided at a different location on the dielectric surface, when each is laminated to form a layer, or when each powder is mixed to form a layer In any case, the above-described effects can be obtained. Embodiment 6 Next, a light emitting device according to Embodiment 6 of the present invention will be described. The light emitting device of the present embodiment is different from the light emitting device of the first embodiment in that the electrode 40 of the light emitting device according to the first embodiment is translucent. The other points are the same as in the first embodiment, and a description thereof will not be repeated.

According to the configuration of this embodiment, the shadow of the electrode 40 is prevented from being reflected on the light emitting surface, and as a result, a more uniform light emitting surface can be obtained. In the case where the dielectric structure 30 is made of, for example, soda-lime glass, if the light-transmitting electrode of the present embodiment is used, an extremely high visible light transmittance is achieved. Note that, in addition to this effect, the same effect as in the first embodiment can be obtained. As a material forming the light-transmitting electrode, for example, indium tin oxide (ITO) can be used from the viewpoint of low resistance and high visible light transmittance.

Next, a method of forming an electrode made of indium tin oxide on the inner surface of the dielectric structure will be described. Since this operation is difficult after the sealing of the substrate, it is performed before the sealing of the substrate. First, an indium tin oxide solution for dip coating (for example, ITO-05C manufactured by High Purity Chemical Co., Ltd.) is prepared,
The dielectric structure is submerged in the solution. Next, the dielectric structure submerged in the solution is pulled up at a constant speed so that the axis of the electrode (the longitudinal direction of the electrode) is vertical, and then the solution adhering to the outer surface of the dielectric structure is sufficiently removed. Wipe off. Finally, after sufficiently drying the dielectric structure, the temperature is 550 ° C.
By firing at about the same level, a dielectric structure having an indium tin oxide film formed on the inner surface is completed. Embodiment 7 A light emitting device according to Embodiment 7 of the present invention will be described with reference to FIG. FIG. 9 schematically illustrates a cross-sectional structure (a cross-sectional structure in a direction perpendicular to the back substrate 10) of the plurality of dielectric structures 33 in the light emitting device according to the present embodiment.

The light emitting device according to the present embodiment differs from the light emitting device according to the first embodiment in that at least one flat portion is provided in the dielectric structure 30 of the light emitting device according to the first embodiment.
Different from the light emitting device. The other points are the same as in the first embodiment, and a description thereof will not be repeated.

Since the light emitting device of this embodiment has the dielectric structure 33 provided with at least one flat portion, it is possible to obtain a more stable and efficient discharge. That is, with such a structure, the electric field distribution in the thickness direction of the discharge vessel becomes uniform, so that optimal energy can be injected into the sealing gas, and as a result, stable and efficient discharge can be obtained. it can. The flat portion does not necessarily need to extend over the whole of the dielectric, and may have a configuration in which a flat portion is provided at any location.

In addition to the above effects, it is needless to say that the same effects as in the first embodiment can be obtained. (Eighth Embodiment) A light emitting device according to an eighth embodiment of the present invention will be described with reference to FIGS.
10 to 14 each schematically show the configuration of the dielectric structure and the electrode (the cross-sectional configuration in a direction parallel to the back substrate 10).

The light emitting device having the configuration shown in FIG. 10 differs from the light emitting device of the first embodiment in that irregularities are periodically provided on the outer surface of the dielectric structure 34. Since the unevenness is periodically provided on the outer surface of the dielectric structure 34, a stable and uniform discharge can be obtained even under a condition in which a uniform discharge is difficult to occur. Under conditions where uniform discharge is unlikely to occur, for example,
In some cases, a rare gas such as xenon, which does not easily diffuse discharge, is sealed at a high pressure.

Under a condition where uniform discharge is unlikely to occur, when attention is paid to a pair of dielectric structures, the discharge generated at the time of voltage application does not spread uniformly, but remains contracted in a single line. . In this state, the light emitting surface also emits light linearly without emitting light uniformly, and furthermore, the danger of damage to the dielectric structure increases due to a sharp increase in current density.

To avoid such a problem, FIG.
As shown in (1), the thickness distribution of the thickness of the dielectric structure is provided periodically in the axial direction (longitudinal direction). With the configuration shown in FIG. 10, the intensity of the electric field intensity is periodically distributed in the axial direction, and a discharge is generated in a thin portion where the electric field intensity is strong. Discharge will occur. In the example shown in FIG. 10, both of the pair of dielectric structures have a structure in which the thickness is changed at both ends of the discharge by forming the structure of the dielectric structure 34 having the changed thickness. ing. On the other hand, the same effect can be obtained by using a structure in which the thickness is changed only at one end of the discharge as in the example shown in FIG.

Further, as shown in FIG. 12, a structure in which a spiral electrode 46 is provided without providing periodic irregularities on the outer surface of the dielectric structure 36, or as shown in FIG. Even in the configuration of the meandering electrode 47, a stable and uniform discharge can be obtained as in the case described above. By periodically creating the distribution of the distance between the electrodes in the axial direction, a discharge can be generated in a portion where the distance between the electrodes is small and the electric field intensity is strong, and as a result, the discharge is periodically generated in the axial direction. Can be. In the case of using a spirally or periodically meandering electrode, as in the case of the above case, a configuration used at both ends of the discharge and a configuration used only at one end of the discharge can be considered. In each case, an effect can be obtained.

Further, as shown in FIG. 14, the same effect can be obtained by changing the shape of the dielectric structure according to the shape of the electrode 48. In the configuration shown in FIG. 14, the shape of the dielectric structure 38 is meandered corresponding to the shape of the meandering electrode 48.

In addition to the above effects, it is needless to say that the same effects as in the first embodiment can be obtained. Embodiment 9 A light emitting device according to Embodiment 9 of the present invention will be described with reference to FIG. FIG.
1 schematically illustrates a configuration (a cross-sectional structure in a radial direction of a discharge vessel 2) of a light emitting device according to the present embodiment.

The light emitting device of the present embodiment is different from the light emitting device of the first embodiment in that the discharge vessel is not flat but cylindrical. The cylindrical discharge vessel 2 is made of a light-transmitting material (for example, soda lime glass), and the inner surface of the discharge vessel 2 has a light emission made of a phosphor or the like as in the first embodiment. A layer 51 is provided. Inside the discharge vessel 2, a plurality of tubular dielectrics 39 made of soda lime glass or the like are arranged at regular intervals while keeping a distance from the inner surface of the discharge vessel 2. It is held at both ends of the discharge vessel 2.

As in the first embodiment, a rare gas such as xenon is sealed in the discharge vessel 2, and an alternating voltage or a pulse voltage is applied to an electrode 49 made of aluminum foil or the like inside the dielectric 39. Then, the first embodiment
Visible light emission can be obtained by the same principle as described above. With such a configuration, a high brightness and uniform cylindrical light emitting device can be obtained. In this embodiment, the same effects as those of the first embodiment can be obtained. (Other Embodiments) In the first to tenth embodiments, the rear substrate 10 and the front substrate 2 are used as the light-transmitting discharge vessels.
0 is sealed with a low-melting glass 8 or a configuration using a cylindrical soda-lime glass.
The present invention can be similarly implemented using other shapes such as spherical glass. Further, both the front substrate and the rear substrate are made of soda lime glass. However, both substrates need not be translucent, and it is sufficient if either one is translucent. Further, since both substrates need only be made of a material or a structure that can withstand the atmospheric pressure, other materials, for example, a light-transmitting ceramic, a light-transmitting resin, or the like can be used. In the case of using a translucent resin, it is desirable to use a material having excellent durability (for example, a material having excellent heat resistance and not deteriorating by ultraviolet rays or the like). A film may be separately provided on a transparent resin.

In the above embodiment, the light emitting layer 50
Although the example using the phosphor for the plasma display panel has been described as (or 51), the present invention is not limited to this. When the rare gas sealed in the discharge vessel (discharge space 100) discharges, other light emitting substances having an excitation band in a wavelength region of ultraviolet light generated when discharge is used can be similarly performed. Further, even when a plurality of kinds of light emitting substances having different light emission wavelengths are mixed and used, the present invention can be similarly implemented.

Further, in the above embodiment, the screen printing is used to form the light emitting layer 50 on the rear substrate 10 and the front substrate 20. However, the present invention is not limited to this, and other methods such as a dip method may be used. The present invention can be similarly implemented.

In the above embodiment, the spacer 6 and the outer frame 70 are used at the time of sealing. However, the outer frame 70 may function as a spacer without using the spacer 6.

In the above embodiment, xenon alone is used at 13.3 kPa as the rare gas to be sealed.
Other gas pressure or other gas, for example, a rare gas such as krypton or helium, or a mixed gas of two or more rare gases, or at least one rare gas and at least one halogen such as iodine or chlorine. The present invention can be similarly carried out using a mixed gas mixture.

In the above embodiment, an example was described in which aluminum foil was used for the electrodes 40 to 49. However, the present invention is not limited to this. For example, a hollow aluminum rod may be used. Further, the material forming the electrode is not limited to aluminum, and another metal such as copper or iron may be used.

Further, in the above-described embodiment, an example has been described in which the plurality of dielectrics 30 to 39 are arranged at equal intervals in parallel to the same plane, but other arrangements, for example, in which the intervals between the dielectrics are different from each other. It is equally feasible to be stepped, intersecting, in any arrangement, or in any shape of dielectric.

In the above embodiment, an example in which an AC pulse voltage of 30 kHz is used as an applied voltage has been described.
Other frequencies, or even if one of the electrodes is grounded, can be similarly implemented.

In the above embodiment, an example in which no reflective material is used outside the discharge vessels 1 and 2 has been described. However, if the direction in which light is extracted is determined, the outer surface of the discharge vessels 1 and 2 may be made of metal or the like. Even if the reflecting material is provided, the present invention can be similarly implemented.

In the above embodiment, the light emitting layer 5
Although the example using 0 and 51 has been described, the present invention is not limited to this.
Even when the discharge vessels 1 and 2 are made of an ultraviolet light transmitting material such as magnesium fluoride without using the light emitting layer, the light emitting device that can emit ultraviolet light can be similarly implemented.

[0115]

As described above, the light emitting device of the present invention has a plurality of electrodes provided in the discharge space, each of which is surrounded by a dielectric structure. can do.

[Brief description of the drawings]

FIG. 1A is a vertical sectional view of a light emitting device according to a first embodiment of the present invention, and FIG. 1B is a horizontal sectional view thereof.

FIG. 2 is a perspective view illustrating an appearance of an outer frame 70 according to the first embodiment.

FIG. 3 is a sectional view showing a modification of the electrode 40 in the first embodiment.

FIG. 4A shows an electrode 40 when an alternating voltage is applied.
4 schematically shows a discharge column 120 generated therebetween, and FIG.
5 schematically shows the discharge column 120 when a direct current (AC) is applied.

FIG. 5 is a horizontal sectional view of a modified example of the light emitting device according to the first embodiment.

FIG. 6 is a horizontal sectional view of a modified example of the light emitting device according to the first embodiment.

FIG. 7 is a cross-sectional view of an electrode 41 according to the second embodiment.

FIG. 8 is a cross-sectional view illustrating a configuration of a dielectric structure 32 and an electrode 42 according to a third embodiment.

FIG. 9 is a cross-sectional view illustrating a configuration of a dielectric structure 33 and an electrode 43 according to a seventh embodiment.

FIG. 10 is a diagram showing a configuration of a dielectric structure 34 and an electrode 44 according to an eighth embodiment.

FIG. 11 is a diagram showing a configuration of a dielectric structure 35 and an electrode 45 according to an eighth embodiment.

FIG. 12 is a diagram showing a configuration of a dielectric structure 36 and an electrode 46 according to an eighth embodiment.

FIG. 13 is a diagram showing a configuration of a dielectric structure 37 and an electrode 47 according to an eighth embodiment.

FIG. 14 is a diagram showing a configuration of a dielectric structure 38 and an electrode 48 according to an eighth embodiment.

FIG. 15 is a perspective view illustrating a configuration of a light emitting device according to a ninth embodiment.

FIG. 16 is a diagram showing a cross-sectional structure of a conventional surface discharge type light emitting device.

FIG. 17 is a diagram showing a cross-sectional structure of a conventional opposed discharge type light emitting device.

FIG. 18 is a diagram illustrating energy levels of xenon.

[Explanation of symbols]

1, 2 discharge vessel 10 back substrate 20 front substrate 30, 31, 32, 33, 34, 35 dielectric structure (glass tube) 36, 37, 38, 39 dielectric structure (glass tube) 40, 41, 42 , 43,44,45,46,47,4
8, 49 electrode 50, 51 light emitting layer 6 spacer 70, 71, 72 outer frame 8 low melting point glass 9 exhaust pipe 100 discharge space 110, 111 lighting power supply 120, 121, 122, 123, 124, 125 discharge plasma 126, 127 , 128,129 Discharge plasma

Claims (16)

[Claims] A discharge vessel having a discharge space therein; and a plurality of electrodes provided in the discharge space, each of which is covered with a dielectric structure and to which an alternating voltage is applied. Light emitting device. 2. The light emitting device according to claim 1, wherein a portion of the dielectric structure other than a portion supported by the discharge vessel is separated from the discharge vessel. 3. The dielectric structure is a glass tube, and each of the plurality of electrodes is disposed inside the glass tube so as not to be exposed to the discharge space, and extends outside the discharge vessel. The light emitting device according to claim 1, wherein the light emitting device is exposed. 4. The light emitting device according to claim 1, wherein each of the plurality of electrodes has a hollow structure. 5. The light emitting device according to claim 1, wherein each of the plurality of electrodes has a mesh structure. 6. The light emitting device according to claim 1, wherein each of the plurality of electrodes has a structure separated into two or more along a longitudinal direction of the dielectric structure. 7. The discharge vessel according to claim 1, wherein at least a part of the discharge vessel has a translucent portion, and at least a part of an inner surface of the discharge vessel is provided with a light emitting layer. The light-emitting device according to any one of the above. 8. The discharge vessel is composed of a front substrate and a rear substrate facing each other, and the plurality of electrodes are arranged at regular intervals, and are parallel to the front substrate or the rear substrate. The light-emitting device according to any one of claims 1 to 7, wherein the light-emitting device is arranged in a plane so as to be arranged. 9. The discharge vessel according to claim 1, wherein a groove for accommodating a part of the dielectric structure and supporting the dielectric structure is provided in the discharge vessel. Light emitting device. 10. The plurality of electrodes according to claim 1, wherein an electrode connected to a high voltage side of a power supply and an electrode connected to a ground side are alternately arranged. A light-emitting device according to any one of the above. 11. An electrode that includes the dielectric structures that are in contact with each other and whose surroundings are covered by the dielectric structures that are in contact with each other are set to the same potential, and the electrodes that are set to the same potential are: The light emitting device according to claim 10, wherein the light emitting device comprises an electrode connected to a high voltage side of the power supply or an electrode connected to a ground side. 12. The light emitting device according to claim 1, wherein the area of the electrodes located at both ends of the plurality of electrodes is half the area of the electrodes located at positions other than the both ends. . 13. One of the plurality of electrodes, wherein one dielectric structure covers the periphery of the electrode,
13. The light emitting device according to claim 12, wherein the areas of the electrodes located at positions other than both ends are substantially equal. 14. The electrodes located at both ends are electrodes whose periphery is covered by one dielectric structure, and the electrodes located at positions other than the both ends are formed by one dielectric structure. Two electrodes having a configuration in which the dielectric structure of the electrode whose periphery is covered are in contact with each other, and the sum of the electrode areas of the two electrodes is twice the area of the electrodes located at the both ends. A light emitting device according to claim 12. 15. The light emitting device according to claim 1, wherein at least a part of a surface of each of the plurality of electrodes is in close contact with the dielectric structure. 16. A discharge vessel having a discharge space therein and at least a rare gas filled as a luminescent substance in the discharge space, and a part other than a part supported by the discharge vessel is separated from the discharge vessel. A plurality of tubes made of a dielectric material provided in the discharge space, and an electrode provided inside each of the plurality of tubes and to which an alternating voltage is applied. The plurality of tubes are arranged in a plane so as to be parallel to the front substrate or the back substrate, and at least a part of the discharge vessel is transparent. A backlight for a flat panel display, comprising: a light-emitting layer; and a light-emitting layer provided on at least a part of an inner surface of the discharge vessel.