JP2001118544A - Fluorescent lamp with outer surface electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent lamp with outer surface electrodes that have superior characteristics of luminous flux rise and starting property and is made long in service life. SOLUTION: In this florescent lamp a glass tube 4 has its inside coated with a plurality of fluorescent film strips 5 arranged with an empty strip-like interval between adjacent film strips 5 along the axis of the glass tube, containing a discharge medium including xenon gas in a sealed manner. A pair of longitudinal electrode strip layers 6a and 6b are deposited on the outside of the glass tube 4 with a given interval between them along the length of the glass tube, thus forming the external electrodes. A conductor or semiconductor layer 7 is partially deposited on the inside of the glass tube, corresponding to one end part of the electrode strip layers 6a and 6b so as to at least partially opposing both the electrode strip layers 6a and 6b. The surface of the conductor or semiconductor layer 7 exposed to the discharge space is at least partially coated with a protective layer 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external electrode fluorescent lamp suitable for reading an original in a scanner or a copying machine, or as a light source for a backlight of a liquid crystal display device.

[0002]

2. Description of the Related Art For example, scanners, copiers, liquid crystal display devices, and the like have been required to have high performance and long life with their widespread use. Are being promoted. That is, this kind of fluorescent lamp (discharge lamp)
Since it is a rare gas discharge, its brightness and discharge voltage are hardly affected by the ambient temperature, and its features such as a long life are utilized.

[0003] As a high performance fluorescent lamp, a glass tube in which a phosphor coating is formed on the inner wall surface along the tube axis leaving a band-shaped region and a rare gas such as xenon is sealed, A pair of strip-shaped electrodes (external electrode layers) connected to external connection leads are integrally formed on the outer peripheral surface of the glass tube over substantially the entire length, one at a wide interval and the other at a narrow interval. An external electrode fluorescent lamp having an additional structure has been developed (JP-A-3-225745, JP-A-4-87249).
JP, JP-A-6-18808, JP-A-9-92226, JP-A-9-92227).

Here, the band-shaped region where the phosphor film is not formed forms an aperture having an increased light transmittance, and the wide interval between the band-shaped electrodes corresponds to the aperture forming portion, and the light-emitting region is formed. Functions as a window that emits light.

FIGS. 9 (a) and 9 (b) show an example of the configuration of a conventional external electrode fluorescent lamp. FIG. 9 (a) is a cross-sectional view, and FIG.
It is a longitudinal section along the aa line of (a).

In FIGS. 9 (a) and 9 (b), reference numeral 1 denotes a hermetically sealed glass tube which functions as an arc tube, and 2 denotes an inner wall surface of the glass tube 1 except for a certain width along the tube axis direction. It is a phosphor film formed. Here, the glass tube 1 has, for example, an outer diameter of about 6 to 10 mm and a length of about 100 to 400 mm, and a rare gas mainly composed of xenon gas as a discharge medium is 23 kPa (200 Torr).
It is sealed with the following sealing pressure.

Further, 3a, 3b is over the tube axis direction almost the entire length on the outer peripheral surface of the glass tube 1, one at wide intervals L _1,
The other narrow pair of strip electrode layer integrally additionally provided at intervals L ₂ of, for example, a width 5~10mm about a conductive film such as thickness. 20 to 100 [mu] m approximately aluminum foil. Here, a pair of strip-shaped electrode layers 3a, 3b are generally while setting the inter-electrode side to be a luminescent emission surface (strip-free portion of the phosphor coating) wider L _1, to obtain a high luminance It is set to the narrow L ₂ between the side serving as the non-emission radiation surface poles.

Further, the outer peripheral surface of the glass tube 1 including the strip-shaped electrode layers 3a and 3b is covered with a light-transmitting resin film, if necessary, for protection. In other words, a configuration is adopted in which the outer peripheral surface of the translucent resin film contributes to protection of the exterior or the glass tube 1 while ensuring insulation such as prevention of creeping discharge in the strip electrode layers 3a and 3b.

The pair of strip-shaped electrode layers 3a and 3b have
A required potential is applied via lead terminals connected by soldering or a conductive adhesive, and external connection leads electrically connected to the lead terminals by soldering.

The external electrode fluorescent lamp is connected to the strip electrode layers 3a, 3b via external connection leads and lead terminals.
The required high-frequency voltage (for example, 20 to 100 KHz,
When power of 1 to 2 KV is supplied), a high-frequency discharge is generated in the glass tube 1 to ionize and excite a rare gas such as xenon gas sealed in the glass tube 1 to emit ultraviolet rays. The emitted ultraviolet light is converted into visible light by the phosphor coating 2 on the inner wall surface of the glass tube 1 and functions as an aperture type fluorescent lamp (light source).

In the configuration of the external electrode fluorescent lamp, the length of the strip-shaped electrode layers 3a and 3b in the tube axis direction is made longer than that of the phosphor film 2 in the tube axis direction to protrude. In some cases.

[0012]

The external electrode fluorescent lamp having the above-mentioned structure is excellent in the luminous flux rising characteristic.
Because of the aperture type, the luminous efficiency is good and the illuminance distribution up to the tube end is uniform. Furthermore, the outer electrodes 3a, 3b
There is an advantage that the light output can be increased by increasing the discharge current by setting a large area for the discharge current. However, on the other hand, there are the following disadvantages. That is, in the case of the above-mentioned external electrode fluorescent lamp, there is no particular problem at the time of lighting and use in a bright place such as during the day, but at the time of lighting and use in a dark place such as at night, it is difficult to obtain initial electrons. Because the starting voltage of the fluorescent lamp itself is high,
There is an inconvenience that it takes time to start the engine.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an external electrode fluorescent lamp having excellent luminous flux rising characteristics and starting properties and a long life.

[0014]

According to a first aspect of the present invention, there is provided a glass tube in which a phosphor film is formed on an inner wall surface along a tube axis and a discharge medium containing xenon gas is sealed. A pair of strip-shaped electrode layers attached to the outer peripheral surface of the glass tube at a required interval over substantially the entire length in the tube axis direction,
A conductive layer or a semiconductor layer provided on the inner wall surface of the glass tube corresponding to one end of the strip-shaped electrode layer so as to at least partially face both the strip-shaped electrode layers, and contacting a discharge space of the conductor layer or the semiconductor layer; An external electrode fluorescent lamp comprising a protective layer covering at least a part of the surface.

According to a second aspect of the present invention, in the external electrode fluorescent lamp according to the first aspect, the conductor layer or the semiconductor layer contains at least one selected from the group consisting of indium oxide, tin oxide and zinc oxide. It is characterized by being.

According to a third aspect of the present invention, in the external electrode fluorescent lamp according to the first or second aspect, the protective layer contains at least one selected from the group consisting of a phosphor, aluminum oxide and magnesium oxide. It is characterized by having.

In the first to third aspects of the present invention, the discharge medium includes xenon gas, a rare gas mainly composed of xenon gas, or a mixed system of the aforementioned rare gas and mercury. The external electrode fluorescent lamp according to the first to third aspects of the present invention employs a method in which when a pair of band-shaped electrode (external electrode) layers are attached to the outer peripheral surface of the light emitting glass tube, the coating is simultaneously protected by a translucent resin film. Can also be taken. And
The coating of the outer peripheral surface with the translucent resin film can be performed by the following means.

For example, a pair of strip-shaped electrode layers is previously supported on one main surface of the light-transmitting resin film piece, and the edge of one of the strip-shaped electrode layers is placed on the edge of the light-transmitting resin film piece. By wrapping and fixing so as to overlap each other, or by fitting a heat-shrinkable resin tube and heat-shrinking, it is possible to simplify the manufacturing process of the press, improve productivity, and easily insulate between the strip-shaped electrode layers. I can do it.

In the first to third aspects of the present invention, the pair of strip-shaped electrode layers provided on the outer peripheral surface of the light emitting glass tube is not limited to a simple strip (linear), but may be, for example, a comb, a waveform, a comb, or the like. Any of the waveforms having different heights or pitches or the light transmission type may be used.

According to the first to third aspects of the present invention, at least a part of one end of both band-shaped electrode layers is provided on the inner wall surface of the glass tube at the end corresponding to the narrow interval between the pair of band-shaped electrode (external electrode) layers. The conductive layer or the semiconductor layer provided to face each other is formed of, for example, indium oxide, tin oxide, zinc oxide, titanium oxide, barium titanate, or a mixture of two or more thereof. The formation of the conductive layer or the semiconductor layer is performed directly on the inner wall surface of the glass tube or with a phosphor film interposed therebetween at one end of both band-shaped electrode layers.

That is, a form in which a conductive layer or a semiconductor layer is formed and arranged on the inner wall surface of the glass tube or the surface of the phosphor coating so as to face one end side of both band-shaped electrode layers, and the both band-shaped electrode layers are dielectrically connected. take.

Here, at the time of lighting, by applying a high-frequency voltage to the strip-shaped electrode layer, a required potential difference is generated between the conductive layer or the semiconductor layer and the strip-shaped electrode layer, and the potential difference causes discharge. That is, since the distance at which the potential difference occurs is the distance between the edge of the conductive layer or the semiconductor layer and the inner wall surface of the glass tube, the distance becomes a very small distance, the electric field becomes strong, and electric discharge easily occurs. . Therefore, the shape such as the thickness and width of the conductive layer or the semiconductor layer is appropriately set in consideration of the high-frequency voltage applied to the strip electrode layer, the material for forming the semiconductor layer, and the like.

In the first to third aspects of the present invention, the conductive layer or the semiconductor layer is at least partially covered with a protective film (protective layer) corresponding to the discharge space. That is, when the conductive layer or the semiconductor layer that contributes to the improvement of the light beam rising characteristic or the startability is exposed to the discharge space, the characteristic is likely to be deteriorated due to deterioration due to irradiation of ultraviolet light or ion bombardment. The inconvenience can be avoided by coating with a protective layer, and the life can be extended.

Here, the protective layer of the conductive layer or the semiconductor layer is formed of, for example, aluminum oxide, magnesium oxide, a phosphor, etc., which have excellent ultraviolet irradiation resistance and ion impact resistance. The protection layer is formed on the surface of the conductive layer or the semiconductor layer exposed to the discharge space, and is generally formed in a state where a part thereof overlaps the phosphor film. Therefore, when the conductive layer or the semiconductor layer is formed directly on the inner wall surface of the glass tube, and the inner wall of the nearby glass tube is exposed, the conductive layer or the semiconductor layer is formed so as to cover the exposed surface of the inner wall of the glass tube between the phosphor film. You.

Further, a slit can be formed in the axial direction of the glass tube so as to bisect the conductive layer or the semiconductor layer. Here, in the case where a slit is provided in a region facing one of the band-shaped electrodes, the conductive layer or the semiconductor layer has a different capacitance because the area surrounded by the band-shaped electrode and the conductive layer or the semiconductor layer is different. The potential difference generated between the strip-shaped electrode and the conductive layer or the semiconductor layer becomes large, and the discharge becomes easy.

On the other hand, when a slit is provided in a region where the interval between the strip electrodes is set relatively narrow, the conductive layer or the semiconductor layer is insulated, and a high electric field is generated in the slit portion to facilitate discharge. .

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, FIGS. 1 (a), (b) and 2 (a)
, (B), FIGS. 3 (a), (b), FIGS. 4, 5, 6 (a), (b)
An embodiment will be described with reference to FIGS. 7 (a) and 7 (b) and FIGS. 8 (a) and 8 (b).

FIG. 1A is a cross-sectional view showing a main part of the external electrode fluorescent lamp according to the first embodiment, and FIG. 1B is a vertical sectional view taken along line AA in FIG. 1A. FIG. Fig. 1 (a)
4B, reference numeral 4 denotes a hermetically sealed glass tube functioning as an arc tube, and reference numeral 5 denotes a phosphor coating formed on the inner wall surface of the glass tube 4 except for a certain width along the tube axis direction. Here, the glass tube 4 has, for example, an outer diameter of 10.0 mm, a wall thickness of 0.5 mm,
It has a length of about 300 mm and is filled with a rare gas as a discharge medium, for example, xenon gas of about 13 kPa.

Further, 6a, 6b is over tube axis direction almost the entire length on the outer peripheral surface of the glass tube 4, one at wide intervals L _1,
The other narrow pair of strip electrode layer integrally additionally provided at intervals L ₂ of, for example, a width of about 10mm, a conductive film such as an aluminum foil having a thickness of about 50 [mu] m. Here, a pair of strip-shaped electrode layers 6a, 6b is typically while setting machining gap side serving as a light-emitting emitting surface (between the facing edges) wider L _1, the non-emission radiation in order to obtain a high illuminance while being set face to become the side machining gap a (between opposing edges) the narrow L _2, it is integrated via an adhesive layer.

Further, reference numeral 7 denotes a strip which is separated from one edge of the phosphor coating 5 on the inner wall surface of the glass tube 4 and which is provided with the strip-shaped electrode layer 6.
a, straddles the narrow L ₂ region between 6b (between opposing edges), a semiconductor layer disposed so as to face the strip electrode layer 6a, a 6b, 8 are coated with the semiconductor layer 7 side Protective layer (protective film). Here, the semiconductor layer 7 is a C-shaped film having a width of about 2 mm and a thickness of about 20 μm mainly composed of, for example, zinc oxide (including about 80% by weight or more), and is within 20 mm inside the end of the glass tube 4. Is formed in a state where the two strip-shaped electrode layers 6a and 6b are connected via the glass tube 4.

The protective layer 8 is a C-shaped film containing aluminum oxide and having a width of about 2 mm and a thickness of about 10 μm.

The external electrode fluorescent lamp having the above configuration is mounted as a reading light source of a scanner reader, and a strip electrode layer is provided.
6a, 6b via power supply means, for example, 20-100 KH
When a high frequency voltage of 1 to 2 KV is applied,
At the voltage between a and 6b, a discharge occurs in the glass tube 4 to emit ultraviolet rays. Here, in a general use environment, the emitted ultraviolet light is converted into visible light by the phosphor coating on the inner wall surface of the glass tube 4 and irradiates the outside of the glass tube 4 with visible light. Acts as a light source.

On the other hand, in the external electrode fluorescent lamp according to this embodiment, the semiconductor layer 7 is arranged on the inner wall surface of the glass tube 4 so as to partially face the external electrode layers 6a and 6b. By applying a high-frequency voltage to the external electrode layer 6a (or 6b), a required potential difference is generated between the semiconductor layer 7 and the external electrode layers 6a and 6b, and a discharge is caused by the potential difference. That is, since the distance at which the potential difference occurs is the distance between the edge of the semiconductor layer 7 and the inner wall surface of the glass tube 4, the distance becomes very small, the electric field becomes strong, and electric discharge easily occurs.

Here, the generation of a large electric field between the semiconductor layer 7 and the external electrode layers 6a and 6b and the easiness of the discharge enable discharge and ultraviolet radiation in a dark environment. Is converted into visible light by the phosphor coating 5 and is irradiated with visible light. In other words, there is provided a fluorescent lamp having high versatility or an environment in which the use environment is not restricted, in which the unstable or insufficient lighting operation in a dark environment, which has conventionally been regarded as a problem, has been eliminated.

In addition, during the discharge / lighting process, the surface of the semiconductor layer 7 exposed in the discharge space region is covered with the protective layer 8 and protected against irradiation of the line of sight and ion bombardment. The fear is reduced, and the required functions are maintained and exhibited for a long period of time. In other words, a highly versatile and long-life external electrode fluorescent lamp that performs stable or sufficient lighting operation even in a dark environment is provided.

FIGS. 2 (a) and 2 (b) are cross-sectional views showing the main configuration of a modified example of the external electrode fluorescent lamp having the above configuration. That is, FIG. 2A is a cross-sectional view, and FIG.
(a) shows a schematic configuration in a longitudinal section along the line BB. This modified example has a structure in which the coating and formation of the protective layer 8 extend not only to the surface of the semiconductor layer 7 but also to the edge of the phosphor coating 5. Other structures and configurations, and actions and behaviors are the same as those in the above-described example, and therefore, detailed description is omitted.

FIG. 3A is a cross-sectional view showing a main part of the external electrode fluorescent lamp according to the second embodiment, and FIG. 3B is a vertical sectional view taken along the line CC of FIG. 3A. FIG. Fig. 3 (a)
4B, reference numeral 4 denotes a hermetically sealed glass tube functioning as an arc tube, and reference numeral 5 denotes a phosphor coating formed on the inner wall surface of the glass tube 4 except for a certain width along the tube axis direction. Here, the glass tube 4 has, for example, an outer diameter of 10.0 mm, a wall thickness of 0.5 mm,
It has a length of about 300 mm and is filled with a rare gas as a discharge medium, for example, xenon gas of about 13 kPa.

Further, 6a, 6b is over tube axis direction almost the entire length on the outer peripheral surface of the glass tube 4, one at wide intervals L _1,
The other narrow pair of strip electrode layer integrally additionally provided at intervals L ₂ of, for example, a width of about 10mm, a conductive film such as an aluminum foil having a thickness of about 50 [mu] m. Here, a pair of strip-shaped electrode layers 6a, 6b is typically while setting machining gap side serving as a light-emitting emitting surface (between the facing edges) wider L _1, the non-emission radiation in order to obtain a high illuminance while being set face to become the side machining gap a (between opposing edges) the narrow L _2, it is integrated via an adhesive layer.

Further, 7 extends over a narrow L ₂ region between the strip-shaped electrode layers 6a and 6b (between the opposing edges) on one end surface of the phosphor coating 5 on the inner wall surface of the glass tube 4. , Strip electrode layer
A semiconductor layer disposed opposite to 6a and 6b;
Is a protective layer (protective film) covering a surface including one side surface of the semiconductor layer 7. Here, the semiconductor layer 7 is a C-shaped film having a width of about 2 mm and a thickness of about 20 μm mainly composed of, for example, zinc oxide (including about 80% by weight or more), and is within 20 mm inside the end of the glass tube 5. Is formed in a state where the two strip-shaped electrode layers 6a and 6b are connected via the glass tube 5.

The protective layer 8 is a film containing aluminum oxide and having a width of about 2 mm and a thickness of about 10 μm.

The external electrode fluorescent lamp having the above configuration is mounted as a reading light source of a scanner reader, and a strip electrode layer is provided.
6a, 6b via power supply means, for example, 20-100 KH
When a high frequency voltage of 1 to 2 KV is applied,
At the voltage between a and 6b, a discharge occurs in the glass tube 4 to emit ultraviolet rays. Here, in a general use environment, the emitted ultraviolet light is converted into visible light by the phosphor coating on the inner wall surface of the glass tube 5 and radiates the visible light to the outside of the glass tube 5. Acts as a light source.

On the other hand, in the external electrode fluorescent lamp according to this embodiment, the semiconductor layer 7 is disposed on the inner wall surface of the glass tube 4 so as to partially face the external electrode layers 6a and 6b. By applying a high-frequency voltage to the external electrode layer 6a (or 6b), a required potential difference is generated between the semiconductor layer 7 and the external electrode layers 6a and 6b, and the potential difference facilitates discharge.

Here, the generation of a large potential difference between the semiconductor layer 7 and the external electrode layers 6a and 6b and the easiness of the discharge enable discharge and ultraviolet radiation in a dark environment. Is converted into visible light by the phosphor coating 5 and is irradiated with visible light. In other words, there is provided a fluorescent lamp having high versatility or an environment in which the use environment is not restricted, in which the unstable or insufficient lighting operation in a dark environment, which has conventionally been regarded as a problem, has been eliminated.

In addition, during the discharge / lighting process, the surface of the semiconductor layer 7 exposed in the discharge space region is covered with the protective layer 8 and protected against irradiation of the line of sight and ion bombardment. The fear is reduced, and the required functions are maintained and exhibited for a long period of time. In other words, a highly versatile and long-life external electrode fluorescent lamp that performs stable or sufficient lighting operation even in a dark environment is provided.

In FIGS. 4 and 5, line A shows the lighting characteristics of the external electrode fluorescent lamp. FIG. 4 shows the lamp lighting time (Hr) and the inverter input voltage Vs at the start of lighting.
FIG. 5 is a relationship diagram between the lamp lighting time (Hr) and the discharge delay time (msec). for reference,
In the configuration of the external electrode fluorescent lamp, a case (line a) of the external electrode fluorescent lamp under the same conditions except that the protective layer 8 is not provided is also shown. As can be seen from the comparison in FIGS. 4 and 5, in the case of the embodiment, not only the initial inverter input voltage Vs is maintained, but also the discharge delay time (msec).
No outbreaks were observed.

FIGS. 6 (a) and 6 (b) are cross-sectional views showing the main configuration of a modified example of the external electrode fluorescent lamp having the above configuration. That is, FIG. 6A is a cross-sectional view, and FIG.
1 shows a schematic configuration in a longitudinal section along the DD line. This modified example has a structure in which a protective layer 8 is coated and formed on the surface of a semiconductor layer 7. And other structures or configurations,
The operation and behavior are the same as those in the above-described example, and a detailed description thereof will be omitted.

FIGS. 7 (a) and 7 (b) are cross-sectional views showing the main configuration of an external electrode fluorescent lamp according to the third embodiment. FIG.
FIG. 7 (a) shows a schematic configuration in a transverse section, and FIG. 7 (b) shows a schematic configuration in a vertical section along the line EE in FIG. 7 (a).
The structure is the same as that of the second embodiment. That is, in the external electrode fluorescent lamp having the structure shown in FIGS. 3A and 3B, the fluorescent film 5, the semiconductor layer 7, and the protective layer 8 are common in a region facing one external electrode layer 6a. The slit 9 has a width of 0.5 mm.

As described above, when the slit 9 is formed in the axial direction of the glass tube so as to bisect the semiconductor layer 7, the semiconductor layer 7 is surrounded by the external electrode layers 6a and 6b and the semiconductor layer 8. Since the area of the portion is different, the capacitance changes, the potential difference between the external electrode layers 6a and 6b and the semiconductor layer 7 increases, and the discharge becomes easier. On the other hand, when the slit is provided in a region where the interval between the strip electrodes is set relatively narrow, the conductive layer or the semiconductor layer is insulated, and a high electric field is generated in the slit portion to facilitate discharge.

FIGS. 8 (a) and 8 (b) correspond to FIGS. 7 (a) and 7 (b).
And (b) are modifications of the external electrode fluorescent lamp having the configuration shown in FIG. In the case of this modification, at a position facing a region where the distance between the external electrode layers 6a and 6b is set to be relatively small, a width of 0.5 mm common to the phosphor coating 5, the semiconductor layer 7 and the protective layer 8 is used. The configuration is such that a slit 9 is provided. 8A is a cross-sectional view, and FIG. 8B is a cross-sectional view of FIG.
1 shows a schematic configuration in a longitudinal section along a line FF.

In the case of the external electrode fluorescent lamp according to the third embodiment, as shown in FIGS. 7 (a) and 7 (b), the slit 9 extends in the axial direction of the glass tube so as to divide the semiconductor layer 7 into two. When the semiconductor layer 7 is formed, since the area of the portion surrounded by the external electrode layers 6a and 6b and the semiconductor layer 8 is different, the capacitance changes, and the external electrode layers 6a and 6b and the semiconductor layer 7 And the potential difference between them increases, and discharge becomes easier.

On the other hand, as shown in FIGS. 8 (a) and 8 (b),
If the external electrode layer 6a, the interval 6b a slit 9 in a region L ₂ which is relatively narrow configured, since the semiconductor layer 9 is insulated, easily discharge occurs high field at the slit portion.

Although the external electrode fluorescent lamp according to the third embodiment is slightly different from those of the first and second embodiments, it can basically exhibit the same operation and effect. confirmed.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the outer diameter and length of the glass tube, the material and shape of the strip-shaped electrode layer, the material of the conductive layer or the semiconductor layer, and the like can be changed as appropriate in accordance with the use and use state of the external electrode fluorescent lamp.

[0054]

As can be seen from the above description, claims 1 to 1
According to the third aspect of the invention, the luminous flux quickly rises without being affected by the use environment such as a bright place or a dark place.
There is provided an external electrode fluorescent lamp having a large amount of light and having characteristics required for reading a document such as a scanner or a copy, or for a backlight of a liquid crystal display device.

Further, since the conductive layer or the semiconductor layer which greatly contributes to the above-mentioned functions and effects is suppressed from being deteriorated or deteriorated by ultraviolet irradiation or ion bombardment, it can be used as an external electrode fluorescent lamp which retains the above-mentioned functions for a long period of time. Function.

[Brief description of the drawings]

FIGS. 1A and 1B show a main configuration of an external electrode fluorescent lamp according to a first embodiment, wherein FIG. 1A is a cross-sectional view, and FIG.
FIG. 4 is a longitudinal sectional view along a line.

FIGS. 2A and 2B show a main configuration of a modified example of the external electrode fluorescent lamp according to the first embodiment, in which FIG.
FIG. 3A is a vertical cross-sectional view along the line BB.

FIGS. 3A and 3B show a main configuration of an external electrode fluorescent lamp according to a second embodiment, wherein FIG. 3A is a cross-sectional view, and FIG.
FIG. 4 is a longitudinal sectional view along a line.

FIG. 4 is a characteristic diagram showing an example of the relationship between the lighting time and the input voltage at the start of lighting of the external electrode fluorescent lamp according to the second embodiment, in comparison with the case of the external electrode fluorescent lamp according to the reference example.

FIG. 5 is a characteristic diagram showing an example of the relationship between the lighting time and the discharge delay time of the external electrode fluorescent lamp according to the second embodiment, in comparison with the case of the external electrode fluorescent lamp according to the reference example.

FIGS. 6A and 6B show a main configuration of a modified example of the external electrode fluorescent lamp according to the second embodiment, in which FIG.
FIG. 3A is a vertical cross-sectional view along the DD line.

FIGS. 7A and 7B show a main configuration of an external electrode fluorescent lamp according to a third embodiment, wherein FIG. 7A is a cross-sectional view, and FIG.
FIG. 4 is a longitudinal sectional view along a line.

FIGS. 8A and 8B show a main configuration of a modified example of the external electrode fluorescent lamp according to the third embodiment, where FIG. 8A is a cross-sectional view and FIG.
FIG. 3A is a vertical cross-sectional view along the line FF.

9A and 9B show an example of a configuration of a main part of a conventional external electrode fluorescent lamp, in which FIG. 9A is a cross-sectional view, and FIG.

[Explanation of symbols]

 1, 4 glass tube 2, 5 phosphor coating 3a, 3b, 6a, 6b strip electrode layer 7 conductor layer or semiconductor layer 8 protection layer 9 slit

Claims (3)

[Claims] 1. A glass tube in which a phosphor film is formed on an inner wall surface along a tube axis and a discharge medium containing a xenon gas is sealed, and an outer peripheral surface of the glass tube is arranged in a tube axial direction. A pair of strip-shaped electrode layers provided at required intervals over substantially the entire length, and a glass tube inner wall surface corresponding to one end of the strip-shaped electrode layer, at least a part of which faces both strip-shaped electrode layers. An external electrode fluorescent lamp comprising: a conductor layer or a semiconductor layer provided; and a protective layer covering at least a part of a surface of the conductor layer or the semiconductor layer in contact with a discharge space. 2. The semiconductor device according to claim 1, wherein the conductor layer or the semiconductor layer contains at least one selected from the group consisting of indium oxide, tin oxide and zinc oxide.
An external electrode fluorescent lamp as described. 3. The external electrode fluorescent lamp according to claim 1, wherein the protective layer contains at least one selected from the group consisting of a phosphor, aluminum oxide and magnesium oxide. .