JP3675319B2 - Rare gas fluorescent lamp manufacturing method and rare gas fluorescent lamp - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a rare gas fluorescent lamp used as a light source for illuminating a document in information equipment such as a facsimile, a copying machine, and an image scanner, and other light sources, and a rare gas fluorescent lamp.
[0002]
[Prior art]
Conventionally, for example, as a lamp for illuminating a document, a pair of strip-like electrodes extending in the lengthwise direction are formed so as to be located on the inner peripheral surface or outer peripheral surface of a tubular discharge vessel via a dielectric layer, A rare gas fluorescent lamp in which a discharge gas mainly composed of a rare gas is enclosed is used.
In the fluorescent lamp having such a configuration, various methods are known as a method for hermetically sealing the opening of the glass tube constituting the discharge vessel.
[Problems to be solved by the invention]
[0003]
For example, there is a method of hermetically sealing a closing member disposed at an open end of a glass tube using frit glass. FIG. 10 shows an example of the structure of a rare gas fluorescent lamp 20 having such a sealing structure. In this example, a disc-shaped main body portion 18 </ b> A having an outer diameter that matches the outer diameter of the glass tube 1 and a protruding plug portion 18 </ b> B having an outer diameter that matches the inner diameter of the glass tube 1 are provided at the opening end of the glass tube 1. A plug-like closing member 18 is disposed, and a gap between the two is hermetically sealed by a frit glass 11 made of low-melting glass, thereby forming a sealing structure.
On the inner peripheral surface of the glass tube 1, a strip-shaped internal electrode 2 extending in the tube axis direction is formed, and a phosphor layer 5 covering the internal electrode 2 is formed. Further, on the outer peripheral surface of the glass tube 1, an external power supply terminal portion 3 extending in the tube axis direction is formed at a corresponding position across the tube wall of the internal electrode 2 and the glass tube 1, and this external power supply A strip-shaped external electrode 4 extending in the tube axis direction is formed at a position separated from the terminal portion 3 in the circumferential direction. The internal electrode 2 and the external power supply terminal portion 3 are formed on the outer end surface of the glass tube 1. They are electrically connected by the formed relay conductive portion 7. Reference numeral 12 denotes a power feeding terminal joint.
[0004]
Thus, in the formation of the sealing structure using the closing member and the frit glass, for example, when a large insulating property and pressure resistance are required, it is necessary to use a sufficiently large amount of the frit glass.
However, when the sealing structure is formed using a large amount of frit glass, the excess portion of the frit glass protrudes radially outward from the outer peripheral surface of the glass tube 1 to form a protruding portion 15. . The protruding height a of the protruding portion 15 is, for example, 0.1 mm or more, and the resulting rare gas fluorescent lamp has a locally increased outer diameter.
[0005]
However, when the fluorescent lamp is used for illuminating a document, in order to obtain a large illuminance, it is preferable that the fluorescent lamp is disposed as close as possible to the object to be illuminated, and the distance between the two is, for example, 0.1 mm. Even if it changes in units, this greatly changes the accuracy of image reading. Therefore, as described above, when a fluorescent lamp having a non-uniform outer diameter due to a local protruding portion or the like is used, there is a problem in that the accuracy of image reading is greatly reduced.
[0006]
Further, in a copying machine or the like, the depth length of the entire apparatus is determined by the total length of the fluorescent lamp for illuminating the document as one factor.
However, in the above-described sealing structure, due to the thickness of the main body portion 18A, a distance b from the outer end portion of the glass tube 1 protrudes outward in the length direction. This distance b is about 5 mm, for example. Furthermore, when such a sealing structure is formed at both ends of the glass tube 1, the total length is 10 mm, and the total length becomes long, making it difficult to reduce the size of, for example, a copying machine. There is a problem that the ratio of the effective light emitting portion to the total length becomes small.
[0007]
The present invention solves the above-described problems and prevents the excess frit glass from protruding outward from the outer diameter of the discharge vessel, despite having a sealing structure using a closing member and frit glass. In addition, it is an object of the present invention to provide a method capable of reliably and easily manufacturing a rare gas fluorescent lamp having a large proportion of the effective light emitting portion in the entire length of the fluorescent lamp.
Another object of the present invention is that the noble gas fluorescent lamp in which the excessive frit glass does not protrude outwardly from the outer diameter of the discharge vessel and the ratio of the effective light emitting portion in the entire length of the fluorescent lamp is large. The purpose is to provide.
[0008]
[Means for Solving the Problems]
The method for producing a rare gas fluorescent lamp of the present invention is a method for manufacturing a rare gas fluorescent lamp in which a gap between an open end portion of a glass tube and a closing member positioned in the open end portion is filled with a frit glass and hermetically sealed. a manufacturing method, placing the closure member having a size that the whole of the glass tube Niso is housed on a support member, a step of placing the unmelted frit glass over the closure member, The step of holding the glass tube in a suspended state by a holding member and accommodating the closing member and the unmelted frit glass in the space at the lower end of the glass tube , and heating and melting the frit glass And the support member supports the closing member so that an excessive amount when the unmelted frit glass is melted is not hindered from protruding downward. To do.
Here, it is preferable that the supporting member is accommodated in the glass tube.
[0009]
Preferably, the support member is integral with the holding member, and a groove for accommodating excess frit glass is formed along a gap formed between the glass tube and the closing member.
[0010]
The rare gas fluorescent lamp of the present invention is formed on a glass tube constituting a discharge vessel, a pair of electrodes disposed on a tube wall of the glass tube via at least a dielectric layer, and an inner peripheral surface of the glass tube. And an open end portion of the glass tube is filled in a closing member positioned in the open end portion and a gap formed between the closing member and the glass tube , It is hermetically sealed by a frit glass formed with a protruding portion that protrudes outward in the length direction of the glass tube from the closing member, and the closing member is outward from the outer end surface of the glass tube. The whole is accommodated in a glass tube so as not to protrude.
The closing member is preferably disc-shaped and its outer end surface substantially coincides with the outer end surface of the glass tube.
[0011]
[Action]
According to the method for manufacturing a rare gas fluorescent lamp of the present invention, the excess of the frit glass used for sealing the glass tube constituting the discharge vessel protrudes outward in the length direction from the end surface of the discharge vessel. Therefore, the outer diameter of the discharge vessel does not increase locally.
Further, since the entire closure member is housed inside the discharge vessel, the fluorescent lamp can be reduced in size, and the outer end surface of the closure member and the outer end surface of the glass tube are approximately matched. Thereby, the ratio of the effective light emission part with respect to the full length of a fluorescent lamp can be enlarged.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
FIG. 1 is an explanatory sectional end view showing a configuration of a fluorescent lamp according to an embodiment of the present invention with a part of a section taken along the axis of the discharge vessel omitted, and FIG. It is sectional drawing for description which shows the state of the cross section along L. FIG.
In this fluorescent lamp 20, a substantially strip-shaped internal electrode 2 extending in the tube axis direction is formed on the inner peripheral surface of a straight tubular glass tube 1 constituting the discharge vessel, and the fluorescent light covering the internal electrode 2 is formed. The body layer 5 is formed except for a part in the circumferential direction, and a light extraction aperture 8 is formed by a part where the phosphor layer 5 is not formed.
[0013]
Further, on the outer peripheral surface of the glass tube 1, a film-like external power feeding terminal portion 3 extending in the tube axis direction in the outer end region thereof corresponds to a position corresponding to the inner electrode 2 and the tube wall of the glass tube 1. In addition, a substantially strip-shaped external electrode 4 extending in the tube axis direction is formed at a position spaced apart from the external power feeding terminal portion 3 in the circumferential direction.
[0014]
On the outer end surface 1A of the glass tube 1, a relay conductive portion 7 made of a conductive film continuous with the internal electrode 2 and the external power feeding terminal portion 3 is formed. Through this relay conductive portion 7, The state where the internal electrode 2 and the external power feeding terminal portion 3 are electrically connected is achieved. Reference numeral 12 denotes a power supply terminal joint to which the power supply terminal is connected.
[0015]
And the opening edge part of the glass tube 1 is airtightly sealed by the closure member 31 and the frit glass 11, and this whole closure member 31 is accommodated in the inside of the glass tube 1, Moreover, the The outer end surface 31 </ b> A is configured to substantially match the outer end surface 1 </ b> A of the glass tube 1.
[0016]
In the above rare gas fluorescent lamp 20, the glass tube 1 constituting the discharge vessel is made of translucent glass, and examples of the material thereof include lead glass, soda lime glass, aluminosilicate glass, and borosilicate glass. it can.
[0017]
The closing member 31 is a disk-shaped or disc-shaped member whose diameter of the maximum diameter portion matches the inner diameter of the glass tube 1, and as a material forming the closing member 31, for example, lead glass, soda lime glass, Examples thereof include aluminosilicate glass and borosilicate glass, but it is preferable to use the same material as the material forming the glass tube 1.
[0018]
The material of the internal electrode 2 or the external electrode 4 is not particularly limited as long as it is conductive. For example, gold, silver, nickel, carbon, gold palladium, silver palladium, platinum, or the like is preferably used. it can.
Specifically, for example, a conductive paste (for example, a so-called silver paste) in which a low-melting glass powder, a metal powder, and a binder are dispersed in an appropriate organic medium is made by using a screen printing method, a vapor deposition method, or the like. The tube 1 can be formed by coating on a target portion or area surface and firing the tube.
[0019]
Further, the external power feeding terminal portion 3 or the relay conductive portion 7 is also formed by coating the target portion or region surface in the form of a film by the same material and method as those of the internal electrode 2 and the external electrode 4 and firing the same. can do.
[0020]
As the material of the phosphor layer 5, known fluorescent materials such as rare earth phosphors and halophosphate phosphors can be used. For example, in order to obtain red visible light, Y ₂ O ₃ : Eu, To obtain (YGd) BO ₃ : Eu and the like, and to obtain green visible light, LaPO ₄ : Ce, Tb, Zn ₂ SiO ₄ Mn, Y ₂ SiO ₄ : Tb, etc. (SrCaBaMg) ₅ (PO ₄ ) ₃ Cl: Eu, 3 BaMgEu) O · 8 Al ₂ O _{3 and the} like.
Such a phosphor layer 5 is formed by applying and baking by a method of sucking up a suspension in which the above-mentioned fluorescent material is dispersed and contained in the glass tube 1, a spraying method, or a pouring method. Is done.
[0021]
As an example of dimensions in the fluorescent lamp 20 having such a configuration, the outer diameter of the glass tube 1 of the discharge vessel shown in FIG. 1 is 6.0 to 10 mm, the inner diameter is 4.9 to 9 mm, and the length is 280 to 365 mm. The length of the power supply terminal joint 12 in the tube axis direction is in the range of 3 to 30 mm. In FIG. 2, the width c in the circumferential direction of the external electrode 4 is 3 to 8 mm, the width d of the portion of the phosphor layer 5 extending beyond the external electrode 4 in the circumferential direction is 2 mm, and exceeds the internal electrode 2 in the circumferential direction. The width e of the portion of the phosphor layer 5 that extends is 1.5 mm, the width f in the circumferential direction of the internal electrode 2 is 2 to 8 mm, and the opening angle α of the aperture portion 8 is 55 to 75 °.
[0022]
In the fluorescent lamp 20, the internal electrode 2 and the external electrode 4 are opposed to each other through the tube wall of the glass tube 1 which is a dielectric, and a dielectric is interposed between them when a high voltage is applied. Barrier discharge occurs, whereby visible light emitted from the phosphor layer 5 is emitted from the aperture portion 8.
[0023]
FIG. 3 is an explanatory cross-sectional view for explaining an example of a method for producing a rare gas fluorescent lamp having the above-described configuration.
This method of manufacturing a rare gas fluorescent lamp basically includes the following steps (a) to (c).
(A) A supporting member having a horizontal support surface 43 that abuts the closing member 31 and the ring-shaped frit glass 111 placed on the closing member 31 along the outer peripheral edge thereof against the lower surface of the closing member 31. A step of supporting by the member 41.
(B) In a state where the straight tubular glass tube 1 constituting the discharge vessel is suspended, it is supported by a support member 41 having a support surface 43 in contact with the lower end surface thereof. A step of accommodating the closing member 31 and the frit glass 111 in the space at the lower end of the glass tube 1.
(C) A step of heating and melting the ring-shaped frit glass 111 by the annular wall 45 and the bottom wall 44 provided with a heater arranged around the lower end portion of the glass tube 1.
[0024]
In the step (a), the support member 41 is a bottomed cylindrical shape having an annular wall 45 having an inner diameter larger than the outer diameter of the glass tube 1 and a bottom wall 44, and is horizontal and flat by the inner surface of the bottom wall 44. A support surface 43 is formed. Further, the annular wall 45 and the bottom wall 44 have a heater function.
An annular groove 42 extending along a gap formed between the outer peripheral surface of the closing member 31 and the inner peripheral surface of the glass tube 1 is formed in the support surface 43 so as to open. Reference numeral 413 denotes a work through hole formed in the center of the support member 41.
The other configuration of the glass tube 1 shown in FIG. 3 is the same as that of the rare gas fluorescent lamp 20 shown in FIG.
[0025]
In this step, the ring-shaped frit glass 111 is in a ring shape as shown in FIG. 4 and has an outer diameter that matches the inner diameter of the glass tube 1.
The material of the ring-shaped frit glass 111 is a low-melting glass that melts at a lower temperature than the material forming the glass tube 1, and the frit glass made of the low-melting glass powder is used, for example, the glass tube It can be manufactured by powder press molding into a ring shape having an outer diameter that matches the inner diameter of 1. The thickness of the ring-shaped frit glass 111 may be equal to or greater than the volume of the gap formed by the inner peripheral surface of the glass tube 1 and the outer peripheral surface of the closing member 31.
[0026]
In the step (b), various holding means can be used as needed in order to hold the glass tube 1 in a vertical state.
And the lower end of the glass tube 1 hold | maintained by the obstruction | occlusion member 31 mounted on the support surface 43 of the support member 41, and the ring-shaped frit glass 111 mounted on this obstruction | occlusion member 31 in the standing state. It accommodates in the space of the lower-end part via opening.
[0027]
In the step (c), the ring-shaped frit glass 111 accommodated in the lower end portion of the glass tube 1 is heated and melted by the support member 41 having the heater function.
The melted frit glass flows into a gap formed between the inner peripheral surface of the glass tube 1 and the outer peripheral surface of the closing member 31, and is then solidified by being cooled to hermetically seal the cylindrical gap. This stops, thereby forming a discharge vessel.
[0028]
Therefore, as the ring-shaped frit glass 111, a glass having a volume larger than the volume of the cylindrical gap is usually used in order to obtain sufficient airtightness and pressure resistance. Therefore, although the frit glass is in an excessive state, the excess flows out downward from the gap due to gravity.
However, since the ring-shaped groove portion 42 is formed at the corresponding portion on the support surface 43 of the support member 41, the excess portion of the frit glass that has flowed out is accommodated in the inside and solidified, and as a result, FIG. As shown, a protruding portion 112 that protrudes outward in the length direction of the glass tube 1 is formed.
[0029]
According to the method for manufacturing the rare gas fluorescent lamp 20 described above, the excess of the frit glass used for sealing the glass tube 1 protrudes in the length direction of the glass tube 1, so that the radial direction is formed on the outer peripheral surface. It does not protrude outward. Therefore, the fluorescent lamp 20 has a uniform outer diameter with no local protrusion.
Further, in the sealing structure to be formed, the closing member 31 is disposed at a position where the outer end surface does not protrude outward from the outer end surface of the glass tube 1. 1 is supported by a common flat support surface 43 on both outer end surfaces thereof, and the positions of the outer end surface of the blocking member 31 and the outer end surface of the glass tube 1 are in the length direction of the glass tube 1. The configuration is consistent with each other. Thereby, while the ratio of the length which the said sealing structure occupies with respect to the full length of the fluorescent lamp 20 can be made small, the ratio of the length of the effective light emission part with respect to the full length of the said fluorescent lamp 20 can be enlarged. it can.
[0030]
As mentioned above, although this invention was demonstrated based on the specific form, this invention is not limited to the above-mentioned example, A various change can be added.
For example, the arrangement of the electrodes in the rare gas fluorescent lamp 20 and the structure such as the power feeding structure to the electrodes are free and are not limited to the above example.
[0031]
In the step (a), the annular wall 45 and the bottom wall 44 of the support member 41 do not have to have a heater function. For example, as shown in FIG. 5, a support having a flat support surface 43 having an annular groove 42 is provided. The ring-shaped frit glass 111 can also be heated by using the member 41 and a separate independent cylindrical heater 46.
Such a heater 46 is not particularly limited, and an appropriate one can be used.
[0032]
Further, as shown in FIG. 6, the support member 41 has a circular shape whose outer diameter is adapted to the inner diameter of the glass tube 1, for example, and fits within the region of the inner peripheral contour of the glass tube 1. It is also possible to use one having In this case, only the closing member 31 is supported on the support surface 43 of the support member 41, and the glass tube 1 is supported in a suspended state by another appropriate means.
Also in this case, the excess portion of the frit glass that flows out from the gap between the outer peripheral surface of the closing member 31 and the inner peripheral surface of the glass tube 1 protrudes downward as it is due to gravity.
[0033]
FIG. 7 shows the closing member of FIG. 6, and this closing member 31 has convex portions 312A and 312B formed in substantially the same shape on the front and back surfaces of the substrate portion 311 on both sides thereof. A stepped portion is formed on the outer peripheral edge. FIG. 8 shows a support member 41 that conforms to the shape of the convex portions 312A and 312B of the closing member 31, and a ridge portion 411 is formed along the outer peripheral edge of the upper surface.
By using such a closing member 31 and the support member 41, the support on the support member 41 of the closing member 31 and the support on the closing member 31 of the ring-shaped frit glass 111 can be reliably ensured without any positional deviation. It can be carried out.
[0034]
Further, as shown in FIG. 9, a closing member 31 having a form in which flange-like convex parts 313A and 313B are formed on the outer peripheral part and a supporting member having a form conforming to the shape of the recessed parts 314A and 314B of the closing member 31 are provided. The effect similar to the above can be acquired also by using.
The frit glass that hermetically seals the glass tube 1 is not limited to the shape processed into a ring shape, and can be processed into a pellet shape, a spherical shape, or the like as long as it can be stably supported. It may be what was done.
[0035]
【Example】
Examples of the present invention will be described below, but the present invention is not limited thereby.
<Example 1>
A silver paste containing silver powder, glass powder and an organic binder is applied to the inner peripheral surface of a glass tube having an outer diameter of 9.8 mm, a wall thickness of 0.55 mm, and an axial length of 360 mm. By drying, an internal electrode having a thickness of 0.005 mm (5 μm), a width of 6 mm, and a length of 352 mm is formed, and the same silver paste is applied to the outer peripheral surface of the glass tube, and then dried. An external electrode having a thickness of 0.006 mm (6 μm), a width of 8 mm, and a length of 352 mm, and an external power feeding terminal portion having a thickness of 0.006 mm (6 μm), a width of 5 mm, and a length of 15 mm were formed.
[0036]
The same silver paste is applied to the outer end surface of the glass tube on which the internal electrode, the external power supply terminal portion, and the external electrode are formed as described above, and dried to obtain a thickness of about 0.1 mm (100 μm). The relay conductive portion was continuously formed at the outer end portion of the internal electrode and the external power feeding terminal portion.
Thereafter, the glass tube was heated in a heating furnace at a temperature of 120 ° C. for 10 minutes, further increased in temperature, and heated at a temperature of 450 ° C. for 20 minutes to be fired.
[0037]
And the said glass tube is hold | maintained in the state which one opening faced down as shown in FIG. 3, and the outer diameter is a disk-shaped obstruction | occlusion member of 8.2 mm inside this opening, and this A ring-shaped frit glass having an outer diameter of 8.2 mm and a volume of 12 to 24 mm ³ was disposed on the upper surface of the closing member. Here, the position of the closing member is accommodated in the glass tube as a whole, and the tube axis of the glass tube and the central axis perpendicular to the radial direction of the closing member are aligned with each other. It is a position where the distance between the peripheral surface and the outer peripheral surface of the closing member is 0.25 mm.
[0038]
Thereafter, the lower end of the glass tube is heated by a cylindrical heater to melt the ring-shaped frit glass, thereby filling the frit glass between the inner peripheral surface of the glass tube and the outer peripheral surface of the closing member. Then, by further natural cooling, the end of the glass tube was hermetically sealed to form a discharge vessel.
When the xenon is sealed in the internal space of the discharge vessel thus formed at a pressure of 10.7 kPa (80 torr), when the input voltage is 24 V and the input current is 0.7 A, the lamp voltage is 1250 V and the lamp current is Produced a noble gas fluorescent lamp with 630 mA and lamp power consumption of 11 W.
In this fluorescent lamp, the illuminance of the light radiated from the aperture portion was 22500 lx at a distance of 8 mm, and the diameter value was uniform at any position in the length direction of the fluorescent lamp.
Further, on the outer end surface of the discharge vessel, a protruding portion of 0.2 to 0.8 mm due to excess frit glass was confirmed, and there was no protrusion outward in the radial direction on the outer peripheral surface of the discharge vessel.
[0039]
【The invention's effect】
According to the method for manufacturing a rare gas fluorescent lamp of the present invention, the excess of frit glass used for sealing the glass tube constituting the discharge vessel protrudes in the length direction of the glass tube. The outer diameter does not increase locally.
Further, since the entire closing member is accommodated in the glass tube, it is easy to achieve downsizing of the fluorescent lamp. In addition, by making the outer end surface of the closing member approximately coincide with the outer end surface of the glass tube, the ratio of the effective light emitting portion to the entire length of the fluorescent lamp can be increased, and thus, for example, miniaturization of a copying machine or the like is achieved. It becomes easy.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory sectional end view showing a configuration of a fluorescent lamp according to an embodiment of the present invention, with a part of a section taken along the axis of a discharge vessel being omitted.
FIG. 2 is an explanatory cross-sectional view showing a state of a cross section along line LL in FIG. 1;
FIG. 3 is an explanatory sectional view showing an example of a method for manufacturing a rare gas fluorescent lamp according to the present invention.
FIG. 4 is an explanatory perspective view showing a ring-shaped frit glass.
FIG. 5 is an explanatory cross-sectional view showing another example of a method for manufacturing a rare gas fluorescent lamp according to the present invention.
FIG. 6 is an explanatory cross-sectional view showing another example of a method for manufacturing a rare gas fluorescent lamp according to the present invention.
FIG. 7 is an explanatory cross-sectional view showing a closing member.
FIG. 8 is a cross-sectional view for explaining a support member.
FIG. 9 is an explanatory sectional view showing a closing member.
FIG. 10 is a cross-sectional view for explaining a conventional example of a rare gas fluorescent lamp with a part omitted in a cross section taken along the axis of a glass tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Glass tube 1A Glass tube outer end surface 2 Internal electrode 3 External power supply terminal portion 4 External electrode 5 Phosphor layer 7 Relay conductive portion 8 Aperture portion 11 Frit glass 111 Ring-shaped frit glass 112 Projection portion 12 Power supply terminal joint portion 15 Projection portion 18 Plug-shaped closing member 18A Main body portion 18B Projecting plug portion 20 Noble gas fluorescent lamp 31 Closing member 31A Closing member outer end surface 311 Substrate portions 312A, 312B Convex portions 313A, 313B Convex portions 314A, 314B Concavities 41 Support member 411 Protruding portion 412 Recessed portion 413 Work through hole 42 Annular groove 43 Support surface 44 Bottom wall 45 Annular wall 46 Heater

Claims (5)

An open end portion of the glass tube, even in this open end gap frit glass between the position occlusive member portion is filled with hermetically sealed rare gas fluorescent lamp manufacturing method of the glass tube Niso Placing a closing member having a size accommodated entirely on the support member, placing an unmelted frit glass on the closing member;
Holding the glass tube in a suspended state by a holding member, and accommodating the closing member and the unmelted frit glass in a space at the lower end of the glass tube;
Heating and melting the frit glass,
Production of a rare gas fluorescent lamp, wherein the supporting member supports the closing member so that an excessive amount when the unmelted frit glass is melted is not hindered from projecting downward. Method.   The method for manufacturing a rare gas fluorescent lamp according to claim 1, wherein the support member is accommodated in the glass tube.   2. The support member is integral with a holding member, and a groove for accommodating excess frit glass is formed along a gap formed between the glass tube and the closing member. The manufacturing method of the noble gas fluorescent lamp of description. A glass tube constituting the discharge vessel, a pair of electrodes disposed on the tube wall of the glass tube via at least a dielectric layer, and a phosphor layer formed on the inner peripheral surface of the glass tube,
The open end of the glass tube is filled in a closing member positioned in the open end and a gap formed between the closing member and the glass tube, and the length of the glass tube is longer than the closing member. It is hermetically sealed by a frit glass formed with a protruding portion that protrudes outward in the vertical direction ,
The closing member is housed in a glass tube as a whole so that it does not protrude outward from the outer end surface of the glass tube.   The rare gas fluorescent lamp according to claim 4, wherein the closing member has a disk shape, and an outer end surface thereof substantially coincides with an outer end surface of the glass tube.

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