JPH10228884A - Fluorescent lamp and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin and long fluorescent lamp with a small diameter and having electrodes in the outer face and which hardly cause flickering even if the dimming level is made high and at the same time provide a fluorescent lamp of which insulating coating surrounding the electrode can easily be formed and in which uneven distribution of wall thickness scarcely exist and provide a lighting system suing the fluorescent lamp. SOLUTION: Xenon and krypton at 90% or less xenon partial pressure ratio are sealed at 100Torr or a lower pressure in a thin and long air-tight container 1 with 5mm or thinner outer diameter, a phosphor layer 2 is formed in the inner face side of the air-tight container 1, and a pair of electrodes 3a, 3b are installed in the outer face of the air-tight container 1, and an insulating coating 4 to surround the electrodes 3a, 3b is formed. Within this defined ranges, the resultant fluorescent lamp can be prevented from flicking even if the dimming level is made high, for example 2% of tubular face brightness. The insulating coating 4 can be formed by evaporation of a polyimide resin, An metal oxide layer may be formed in the inner face of the air-tight container 1 or alumina is mixed with the phosphor layer 2 or an alumina layer may be formed in one end part of the air-tight container 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp having a small-diameter and elongated airtight container and a lighting device using the same.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view of a first conventional fluorescent lamp for a pointer.

In the figure, 81 is an airtight container, 82 is a phosphor layer, 83 is an internal electrode, 84 is an external electrode, 85 is a light-shielding and insulating coating, 86 is a light-guiding window, 87 is one terminal, and 88 is the other terminal. , 89 are lead wires.

The hermetic container 81 has, for example, an outer diameter of 2.4 m.
m, a straight tubular light-transmitting glass bulb with a length of 50 to 70 mm, with a partial pressure ratio of xenon 40% and neon 60
% To 90 torr.

[0005] The phosphor layer 82 is formed on the inner surface of the airtight container 81.

The internal electrode 83 is formed of a nickel rod connected to the end of the lead wire 89 sealed through the one end of the airtight container 81 in the airtight container 81.

[0007] The outer electrode 84 is formed by screen-printing a conductive paint on the outer surface of the hermetic container 81 along the longitudinal direction of the hermetic container 81, drying and firing.

The light-shielding / insulating coating 85 is formed by applying and drying an epoxy resin ink by screen printing, and insulates the outer surface electrode 84 from the outside, forms a light lead-out window 86, and forms other parts of the airtight container 81. The part is shielded from light.

One terminal 87 is coated with silver paste,
It is formed by drying and baking, and is attached to the end of the hermetic container 81 so as to cover a portion of the lead wire of the internal electrode 83 which extends to the outside from the hermetic container 81.

The other terminal 88 is formed of a silver paste similarly to the one terminal 87, and penetrates the insulating coating 85 to be connected to the external electrode 84.

Then, when the output terminals of the lighting device are connected to both terminals 87 and 88 and the lamp is lit at a lamp current of 3 to 5 mA,
Discharge occurs between the internal electrode 83 and the external electrode 84, and the generated ultraviolet light excites the phosphor layer 82, emits visible light, and emits white light from a light extraction window 86 formed in the insulating coating 85. The screen brightness at this time was 2000 cd /
m ² .

FIG. 9 is a sectional view of a reading fluorescent lamp according to a second prior art.

In the figure, 91 is an airtight container, 92 is a phosphor layer, 93a and 93b are external electrodes, 94 is a light-transmitting insulating coating, and 95a and 95b are terminals.

The airtight container 91 is, for example, a straight tubular translucent glass bulb having an outer diameter of 6 mm and a length of 200 to 300 mm, and contains xenon at 80 to 100 torr.

The phosphor layer 92 is formed on the inner surface of the airtight container 91.

The outer electrodes 93a and 93b are connected to an airtight container 91.
Are disposed on the outer surface of the airtight container 91 so as to be spaced apart from each other along the longitudinal direction. A light-shielding coating may be formed on the outer electrodes 93a and 93b except for a part so as to form a light exit window.

The insulating coating 94 is formed of, for example, a translucent heat-shrinkable tube, and is formed on the entire peripheral surface of the airtight container 91.

The terminals 95a and 95b are light-shielding and insulating coatings 9
4, a silver paste is applied, dried and fired.

When the output terminal of the lighting device is connected between the terminals 95a and 95b and the lamp is lit at a lamp current of 10 to 20 mA, a discharge is generated between the outer electrodes 93a and 93b, and the brightness of the light guide window is reduced. It is about 5000 cd / mm ² .

[0020]

The first and second prior arts have a problem that flicker in brightness tends to occur when the dimming degree is increased. In the first prior art, since one of the electrodes is an external electrode, the spread of discharge can be obtained as compared with the case where both electrodes are internal electrodes. Flickering occurs.

On the other hand, in the second prior art, since both electrodes are external electrodes, a relatively good discharge spread can be obtained, but the tube diameter is as large as 6 mm and xenon is 80 to 100 torr. Due to the encapsulation, the flicker of brightness is larger than that of the first prior art.

This type of fluorescent lamp is not limited to the case where it is used, for example, as a pointer for an in-vehicle instrument, but the fact that a wide range of dimming is possible without the flicker of brightness means that comfortable lighting can be produced. Which is therefore preferred.

Also, in the first prior art, in particular, since the epoxy resin is applied by screen printing to the insulating coating, variations in the amount of application occur, and when used as a guide, it is difficult to balance the weight. It took time. Not only that, but also in the formation of the light-shielding and insulating coating,
The number of steps is large and the cost is high. In addition, there is a problem that the light-shielding and insulating coating is deteriorated due to long-time lighting, and is easily peeled off.

Further, the second prior art also has a problem that the heat-shrinkable tube is deteriorated by long-time lighting.

It is a first object of the present invention to provide a small and long fluorescent lamp in which brightness does not easily flicker even if the dimming degree is increased, and a lighting device using the same.

It is a second object of the present invention to provide a small and long fluorescent lamp which is easy to form a light-shielding or insulating coating and which can easily keep the amount of coating, and a lighting device using the same.

[0027]

According to the first aspect of the present invention, there is provided a fluorescent lamp having a translucent elongated airtight container having an outer diameter of 5 mm or less; a phosphor layer formed on an inner surface side of the airtight container; A rare gas consisting of xenon and krypton containing 90% or less of xenon at a partial pressure ratio sealed at a pressure of 100 torr or less; and a pair of electrodes disposed on the outer surface of the hermetic container. And

In the present invention and the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

The airtight container is preferably made of a soft glass such as soda lime glass or lead glass. However, if necessary, a hard glass such as borosilicate glass or a material other than glass can be used as a light-transmitting and air-tight material. Any material that satisfies the fire resistance and workability at the operating temperature is acceptable.

The cross-sectional shape of the airtight container is free as long as it has an outer diameter of 5 mm or less and is elongated. For example, a circular, elliptical or quadrangular cross section can be adopted. The reason for limiting the outer diameter to 5 mm or less is as follows. That is, when the outer diameter exceeds 5 mm, flickering of brightness tends to occur. Outer diameter is 5m
m or less, the thickness of the airtight container is generally 0.2 to 0 m.
Since it is about 5 mm, the inner diameter is 4 to 4.6 mm or less.

The length of the airtight container is not particularly limited, but is generally preferably about 50 to 300 mm.

The phosphor layer is formed directly or indirectly on the inner surface of the hermetic container. Indirect includes, for example, first forming a protective layer of an intermetallic oxide layer made of alumina and / or titanium oxide on the inner surface of the hermetic container, and forming a phosphor layer on the inner surface of the protective layer. As the phosphor used,
A three-wavelength emission rare earth phosphor, a calcium halophosphate phosphor, or the like can be freely selected. The emission color may be white or a specific color.

Further, other substances may be mixed in the phosphor layer in addition to the phosphor, if desired.

The rare gas sealed in the airtight container is a mixed gas of xenon and krypton, and may be xenon-rich or krypton-rich. The reason for reducing the content of xenon to 90% or less is as follows. That is, if it exceeds 90%, although it changes depending on the sealing pressure and the presence or absence of auxiliary means, the flicker of brightness tends to occur even under relatively shallow dimming or full light. Further, when xenon is not contained, the flicker of brightness is likely to occur due to relatively shallow dimming, and the brightness also decreases, which is not possible.

The reason for limiting the noble gas filling pressure to 100 torr or less is as follows. That is, 100 to
If it exceeds rr, it will vary depending on the ratio of the rare gas charged, the charged pressure, and the presence or absence of auxiliary means, but it is not possible because flickering of brightness tends to occur at least at a desired deep dimming degree.

The electrode may be formed by attaching a thin metal plate such as aluminum to the outer surface of the airtight container with an adhesive, or by applying a conductive metal paste, drying and firing. If desired, a metal may be deposited by vapor deposition or other deposition methods to form the electrodes. In general, the electrodes are arranged so as to face each other along the longitudinal direction of the airtight container.

A necessary insulating distance is provided between the electrodes, and a window for guiding light generated in the airtight container is formed. Then, it is possible to form a light-shielding property so as not to emit light from portions other than the window and to form an insulating coating.
If necessary, the light-shielding member and the insulating member can be separately provided. The windows are often slit-shaped. A pair of gaps are formed between the electrodes,
One of them can be covered with a light shielding member to form a window only in one gap. A single window is preferred when used for instrument pointers or reading. However, a pair of windows can be formed if required for other applications.

Thus, the fluorescent lamp of the present invention hardly causes a flicker of brightness even in required dimming, and has a required tube surface luminance.

The fluorescent lamp according to the second aspect of the present invention is the first aspect of the present invention.
The fluorescent lamp described above is characterized in that a metal oxide layer having an average particle size of 1 μm or less is provided between the hermetic container and the phosphor layer.

As the metal oxide, alumina, titanium oxide and the like can be used. A metal oxide layer may be formed on the inner surface of the hermetic container, and then a phosphor layer may be formed.

Thus, the metal oxide layer has the function of reducing the flicker of brightness, although the mechanism is not clear.

The fluorescent lamp according to the third aspect of the present invention has an outer diameter of 5
mm; a light-transmitting elongated airtight container having a diameter of 1 mm or less; a metal oxide layer having an average particle diameter of 1 μm or less formed on the inner surface of the airtight container; a phosphor layer formed on an inner surface of the metal oxide layer; A rare gas composed of xenon and krypton containing 10 to 50% or less of xenon at a partial pressure ratio sealed at a pressure of 100 torr or less; and a pair of electrodes disposed on the outer surface of the hermetic container. Features.

In the present invention, due to the combination of the metal oxide layer and the above-mentioned partial pressure ratio of xenon, the brightness flickers even in the most part of the range even if the tube surface brightness is adjusted to 2% of the maximum value. Does not occur.

The fluorescent lamp according to the fourth aspect of the present invention is the second aspect of the present invention.
Or the fluorescent lamp according to 3, wherein the metal oxide layer is
It is characterized by containing at least one of alumina and titanium oxide.

According to the present invention, by configuring the metal oxide layer as described above, it is possible to prevent the flicker of brightness and / or improve the performance.
Alumina mainly prevents flicker of brightness, and titanium oxide mainly functions to prevent rare gas from entering the wall of the hermetic container. As the rare gas penetrates into the wall of the hermetic container during operation, the pressure of the filled gas decreases, and accordingly the brightness of the tube surface decreases, so that the prevention by the titanium oxide is effective.

The fluorescent lamp according to the fifth aspect of the present invention has an outer diameter of 5 mm.
a translucent elongated airtight container having a diameter of not more than 1 mm; a phosphor layer formed on the inner surface of the airtight container; and 10 to 50% of xenon in a partial pressure ratio enclosed in the airtight container at a pressure of 80 torr or less.
A rare gas comprising xenon and krypton, and a pair of electrodes disposed on the outer surface of the airtight container.

According to the present invention, even if the phosphor layer is formed directly on the inner surface of the hermetic container by setting the noble gas filling pressure and the partial pressure ratio as described above,
No flickering of the brightness occurs even when the screen brightness is adjusted to 2% of the maximum value.

The fluorescent lamp according to the sixth aspect of the present invention is the first aspect of the present invention.
6. The fluorescent lamp according to any one of Items 5 to 5, further comprising an alumina layer adjacent to the phosphor layer at an end of the airtight container.

According to the present invention, the provision of the alumina layer at the end of the tube improves the darkness characteristics of the fluorescent lamp. The alumina layer is easily formed by forming a metal oxide layer containing alumina on the inner surface of the hermetic container and forming a phosphor layer on the metal oxide layer while leaving one end of the metal oxide layer. Can be. However, if necessary, after forming the phosphor layer on the inner surface of the hermetic container, the phosphor layer at one end of the hermetic container may be removed, and the alumina layer may be formed there.

Therefore, the alumina layer needs to contain at least alumina, but it allows other substances to be mixed. For example, it may contain titanium oxide in an appropriate amount.

The fluorescent lamp according to the seventh aspect of the present invention is the first aspect of the present invention.
7. The fluorescent lamp according to any one of Items 6 to 6, wherein the phosphor layer contains alumina fine particles interposed between the phosphor particles.

In the present invention, the dark characteristics can be improved. Since the phosphor layer may be simply formed by mixing alumina with the phosphor in advance, the production is simple. If necessary, the darkness can be further improved by forming an alumina layer at one end in the airtight container.

The fluorescent lamp according to the eighth aspect of the present invention is the first aspect of the present invention.
8. The fluorescent lamp according to any one of items 7 to 7, further comprising an insulating coating made of a polyimide resin vapor-deposited film and covering at least an outer surface electrode.

In the present invention, since the insulating coating is formed by depositing a polyimide resin, the weight of the insulating coating is not partially ubiquitous. For this reason, when the fluorescent lamp is used as a pointer of an instrument, it is easy to balance the weight. Further, the number of manufacturing steps is reduced, so that the cost can be reduced.

Further, by increasing the blending ratio of oxydianiline, which is a component of the polyimide resin, or by raising the firing temperature to make it black, insulation and light shielding can be realized by one coating. However, in order to further improve insulation, a transparent silicone resin may be coated on the entire fluorescent lamp.

The fluorescent lamp according to the ninth aspect of the present invention is the first aspect of the present invention.
9. The fluorescent lamp according to any one of items 1 to 8, further comprising: an insulating coating covering at least a surface of the electrode; being connected to each electrode through the insulating coating and being disposed at different positions in the axial direction of the hermetic container. And a pair of terminals provided.

In the present invention, the insulating coating is preferably formed by depositing a polyimide resin, but may be coated with a polyimide resin. Further, the insulating coating is not limited to the polyimide resin, and other insulating materials such as a silicone resin can be used.

The terminal may be at a position facing any part of the airtight container as long as it is connected to each electrode. However, in order to utilize the light emission of the fluorescent lamp, it is generally convenient to locate it near one end of the hermetic container.

Thus, in the present invention, since the terminals are arranged at different positions in the axial direction of the airtight container, it is easy to secure an insulation distance between the terminals. In addition, it is easy to support the fluorescent lamp and make an electrical connection to the terminal.

According to a tenth aspect of the present invention, there is provided a lighting device, comprising: a lighting device main body; and the fluorescent lamp according to any one of the first to ninth aspects supported by the lighting device main body. .

In the present invention, the illuminating device is applicable to any device utilizing the emission of a fluorescent lamp, such as a luminaire, a backlight of a liquid crystal or the like, a reading device of an OA device, an illuminating pointer of a vehicle-mounted instrument.

[0062]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of the fluorescent lamp of the present invention.

In the figure, 1 is an airtight container, 2 is a phosphor layer, 3a and 3b are electrodes, 4 is an insulating coating, 5a and 5b are terminals, and 6 is an alumina layer.

The airtight container 1 has an outer diameter of 5.0 mm and a thickness of 0.1 mm.
It consists of a glass bulb 5 mm long and 200 mm long.

The phosphor layer 2 is formed on the inner surface of the hermetic container 1 using a three-wavelength light emitting phosphor.

The electrodes 3a and 3b are formed by bonding aluminum thin plates to the outer surface of the airtight container 1 in a state where the thin plates are spaced apart from each other along the axial direction of the airtight container 1.

The insulating coating 4 is formed by evaporating a black polyimide resin so as to surround the electrodes 3a and 3b from outside. Therefore, the insulating coating 4 also serves as a light shielding film. When the insulating coating 4 is formed, a predetermined portion of each of the light exit window and the terminal is masked along the axis of the airtight container 1 between the electrodes 3a and 3b. When the masking of the light exit window is removed, a light exit window (not shown) is formed.

The terminals 5a and 5b are coated with a silver paste after removing the masking of the predetermined portions of the insulating coating and dried,
It is formed by firing, and is disposed at a position separated from each other in the axial direction of the airtight container 1. And terminals 5a, 5
b slightly protrudes from the surface of the insulating coating 4 to facilitate connection of the connector of the lighting device.

The alumina layer 6 is formed at one end of the hermetic container 1 and adjacent to the phosphor layer 2. The alumina layer 6 works to improve the dark characteristics of the fluorescent lamp. That is, when the fluorescent lamp is turned on in the dark, initial electrons are emitted from the alumina layer.
It can be started almost instantly. The alumina layer can be omitted when the dark characteristics are not a problem or when the dark characteristics are improved by other means.

Xenon and krypton are sealed in the airtight container 1 at a predetermined ratio at a predetermined pressure.
Various combinations were manufactured and their performances were compared.

Table 1 shows the results of measuring the degree of flicker in the lighting state with respect to changes in the mixture ratio of the rare gas and the pressure of the sealed gas in the fluorescent lamp.

[0073]

[Table 1] As is clear from Table 1, when xenon was 90% or less and the filling pressure was 100 torr or less, no flickering of brightness was observed in the all-light state. Xenon is 70%
Below, when the sealing pressure was 80 torr or less, no flickering of the brightness occurred even when the light was adjusted to adjust the tube surface brightness to 50% of the full light. Also, when the xenon content was 50% or less and the filling pressure was 80 torr or less, no flickering of the brightness occurred even if the tube surface brightness was adjusted to 10% of the total light. Further, the filling pressure is 30 torr when xenon is 50% or less, and the filling pressure is 50 torr when xenon is 30%.
When r and xenon were 10% and the filling pressure was 80 torr, no flickering of the brightness occurred even when dimming the tube surface luminance to 2% of the total light.

FIG. 2 is a perspective view showing a second embodiment of the fluorescent lamp of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment has the same structure as that of FIG. 1 except that a thin metal oxide layer 7 is formed on the inner surface of the airtight container 1 and that no alumina layer is provided. The metal oxide layer 7 has an average particle size of 1 μm or less and is made of alumina and / or titanium oxide. The phosphor layer 2 is formed on the metal oxide layer 7.

Table 2 shows the fluorescent lamp shown in FIG.
The result of measuring the degree of flickering of the brightness in the lighting state with respect to the change of the mixture ratio of the rare gas and the charged gas pressure is shown.

[0078]

[Table 2] As is clear from Table 2, when the xenon content was 90% or less and the filling pressure was 100 torr or less, no flickering of the brightness in the all-light state was observed. When the xenon content was 90% or less and the filling pressure was 80 torr or less, no flickering of the brightness occurred even if the dimming was performed to diminish the tube surface brightness to 50% of the full light. Xenon is 70% or less, the filling pressure is 80 torr or less, xenon is 50% or less, the filling pressure is 100 torr or less, and xenon is 30% or less.
% Or less and the filling pressure was 120 torr or less, no flickering of brightness occurred even when the tube surface brightness was adjusted to 10% of the total light. Further, the filling pressure is 50 torr when xenon is 50% or less, and the filling pressure is 80% when xenon is 30%.
10% torr and xenon and 100 tons filling pressure
At rr, no flickering of brightness occurred even when the tube surface brightness was adjusted to 2% of the total light.

FIG. 3 is a perspective view showing a fluorescent lamp according to a third embodiment of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment is a small-sized fluorescent lamp suitable as a pointer for a vehicle-mounted instrument. That is, the airtight container has an outer diameter of 2.4 mm and a length of 60 mm.

The rare gas is sealed with 80 torr of xenon 10% and krypton 90% in partial pressure ratio.

A metal oxide layer in which alumina and titanium oxide were mixed at a weight ratio of 1: 1 was formed on the inner surface of the hermetic container, and a phosphor layer was formed except for one end of the metal oxide layer. A portion of the metal oxide layer where no phosphor is formed forms an alumina layer.

The phosphor is of a three-wavelength emission type (green; LaPO
4: Ce, Tb, blue; BaMgAl ₁₄ O ₂₃ : Eu ²⁺ ,
Red; (Y, Gd) BO ₃ : Eu) was used. The phosphor was mixed with 1% by weight of alumina fine particles.

Reference numeral 8 denotes a light guide window, which is formed to have a width of 1 mm along the axial direction of the airtight container.

Although not shown, the electrodes have a width of 1.5 mm.

The insulating coating 4 is formed by depositing a polyimide resin to a thickness of 30 μm by vapor deposition. The weight variation of the lamp due to the thickness variation of the insulating coating was negligible. In the case of the related art, a weight variation of about 30 mg occurred.

Then, both terminals of this fluorescent lamp are
When the lamp was lit at 5 mA with a lamp current of 5 mA when connected to a high frequency power supply of 1,500 V at KHz, the luminance of the display was 2000 cd / m
² was obtained. In addition, there was no problem with the dielectric strength up to 3000 V AC. Further, no flickering of the brightness occurred even when dimming was performed at a cycle of 100 Hz by the PWM method until the screen luminance reached 2% of the total light.

FIG. 4 illustrates a change in relative lamp surface luminance with respect to the lighting time of the fluorescent lamp of the embodiment shown in FIG. 3 and a comparative fluorescent lamp having the same configuration except that titanium oxide is not contained in the metal oxide layer. It is a graph to do.

In the figure, curve A is the fluorescent lamp shown in FIG. 3, and curve B is the fluorescent lamp for comparison. After a lighting time of about 10,000 hours has elapsed, the fluorescent lamp containing titanium oxide has a significantly smaller decrease in the screen luminance than the fluorescent lamp for comparison.

Next, the test results for the dark characteristics will be described.

The tests were performed for (1) a fluorescent lamp having the same structure as that of FIG. 3 except that alumina was not used, (2) a fluorescent lamp in which only 1% by weight of alumina was mixed in the phosphor layer, and (3)
There are five types of fluorescent lamps, namely, a fluorescent lamp in which only 5% by weight of alumina is mixed in the phosphor layer, (4) a fluorescent lamp in which only an alumina layer is formed at one end of an airtight container, and (5) a fluorescent lamp in FIG. There were 50 prototypes each for testing.

The test conditions were as follows: after standing in a bright place for 12 hours, and then in darkness for 12 hours, repeating for 168 hours, and then in darkness for 1 hour to measure the average lighting delay time.

As a result, (1) is 253 seconds and (2) is 7 seconds.
6 seconds, (3) was 3.9 seconds, (4) was 0.2 seconds, and (5) was 0.1 seconds.

FIG. 5 is an enlarged sectional view conceptually showing a section of a fourth embodiment of the fluorescent lamp of the present invention.

In this embodiment, the airtight container 1 has an elliptical cross section. Reference numeral 4 denotes an insulating coating, but illustration of the phosphor layer, electrodes, terminals, and the like is omitted, including FIG.

FIG. 6 is an enlarged sectional view conceptually showing a section of a fifth embodiment of the fluorescent lamp of the present invention.

In the present embodiment, the cross-sectional shape of the airtight container 1 is set to 4
It is a square.

FIG. 7 is an exploded perspective view showing a main part of an on-vehicle instrument as one embodiment of the lighting device of the present invention.

In the figure, the same parts as those in FIG.

In this embodiment, a fluorescent lamp is incorporated as a pointer of an instrument, 9 is a rotating shaft of the instrument, and 10 is a connector and lamp support.

The rotating shaft 9 extends from an instrument body (not shown).

The connector / lamp support 10 has a rotating shaft 9
And the fluorescent lamp terminals 5a, 5b
Is held from the outside to mechanically support the fluorescent lamp and electrically connect to the lighting device. A lead wire passes through the inside of the rotating shaft.

[0104]

According to each of the first to eighth aspects of the present invention, it is possible to provide a small-diameter and elongated fluorescent lamp in which the flicker of brightness is less likely to occur even when the dimming degree is increased.

According to the second aspect of the present invention, in addition to the above, by providing a metal oxide layer on the inner surface of the hermetic container, it is possible to provide a fluorescent lamp with less flicker in brightness.

According to the third aspect of the present invention, in addition to the provision of the metal oxide layer and the inclusion of 10 to 50% of xenon, the brightness of the tube surface can be adjusted to 2% of the maximum value within most of the range. Thus, it is possible to provide a fluorescent lamp that does not cause flicker in brightness.

According to the fourth aspect of the present invention, there is provided a fluorescent lamp having a metal oxide layer containing at least one of alumina and titanium oxide, thereby preventing flicker of brightness and / or improving performance. be able to.

According to the fifth aspect of the present invention, since a rare gas having a xenon content of 10 to 50% and an encapsulation pressure of 80 torr or less is encapsulated, even if there is no metal oxide layer, almost all of the metal oxide layer is covered. Thus, it is possible to provide a fluorescent lamp that does not cause flicker in brightness even when the tube surface brightness is adjusted to 2% of the maximum value.

According to the invention of claim 6, in addition to the provision of the alumina layer at the end in the airtight container, it is possible to provide a fluorescent lamp having good darkness characteristics.

According to the seventh aspect of the present invention, a fluorescent lamp having good darkness characteristics can be provided by additionally including alumina fine particles between the phosphor particles.

According to the eighth aspect of the present invention, in addition, by providing an insulating coating formed by vapor deposition of a polyimide resin, it is possible to provide a fluorescent lamp in which the weight variation of the insulating coating is small and the cost can be reduced.

According to the ninth aspect of the present invention, it is possible to provide a fluorescent lamp which can easily secure the insulation distance between the terminals and can perform the electrical connection simultaneously with the mechanical support of the fluorescent lamp.

According to the tenth aspect, it is possible to provide a lighting device having the effects of the first to ninth aspects.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a fluorescent lamp of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the fluorescent lamp of the present invention.

FIG. 3 is a perspective view showing a third embodiment of the fluorescent lamp of the present invention.

4 is a graph illustrating a change in relative tube surface luminance with respect to lighting time of the fluorescent lamp of the embodiment shown in FIG. 3 and a comparative fluorescent lamp having the same configuration except that titanium oxide is not included in the metal oxide layer.

FIG. 5 is an enlarged sectional view conceptually showing a section of a fourth embodiment of the fluorescent lamp of the present invention.

FIG. 5 is an enlarged sectional view conceptually showing a section of a fifth embodiment of the fluorescent lamp of the present invention.

FIG. 7 is an exploded perspective view of a main part of a vehicle-mounted instrument as one embodiment of the lighting device of the present invention.

FIG. 8 is a cross-sectional view of a first conventional fluorescent lamp for a pointer.

FIG. 9 is a sectional view of a reading fluorescent lamp according to a second prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Airtight container 2 ... Phosphor layer 3a ... Electrode 3b ... Electrode 4 ... Insulating coating 5a ... Electrode 5b ... Electrode

Claims (10)

[Claims] 1. A light-transmitting elongated airtight container having an outer diameter of 5 mm or less; a phosphor layer formed on an inner surface side of the airtight container; and a xenon with a partial pressure ratio sealed in the airtight container at a pressure of 100 torr or less. A rare gas comprising xenon and krypton containing 90% or less of nitrogen and a pair of electrodes disposed on an outer surface of the hermetic container. 2. An average particle size of 1 μm between an airtight container and a phosphor layer.
The fluorescent lamp according to claim 1, comprising a metal oxide layer having a thickness of not more than m. 3. A light-transmitting elongated airtight container having an outer diameter of 5 mm or less; a metal oxide layer having an average particle diameter of 1 μm or less formed on an inner surface of the airtight container; and an inner surface of the metal oxide layer. A phosphor layer; a rare gas composed of xenon and krypton containing 10 to 50% xenon at a partial pressure ratio sealed in the hermetic container at a pressure of 100 torr or less; and a pair of electrodes disposed on an outer surface of the hermetic container; A fluorescent lamp comprising: 4. The fluorescent lamp according to claim 2, wherein the metal oxide layer contains at least one of alumina and titanium oxide. 5. A light-transmitting elongated airtight container having an outer diameter of 5 mm or less; a phosphor layer formed on an inner surface of the airtight container; and xenon at a partial pressure ratio enclosed in the airtight container at a pressure of 80 torr or less. A fluorescent lamp comprising: a rare gas containing 10 to 50% of xenon and krypton; and a pair of electrodes disposed on an outer surface of an airtight container. 6. The fluorescent lamp according to claim 1, further comprising an alumina layer adjacent to the phosphor layer at an end of the hermetic container. 7. The fluorescent lamp according to claim 1, wherein the phosphor layer contains alumina fine particles interposed between the phosphor particles. 8. The fluorescent lamp according to claim 1, further comprising an insulating coating made of a polyimide resin vapor-deposited film and covering at least an outer electrode. 9. An insulating coating covering at least the surface of the electrode;
A pair of terminals penetrating the insulating coating and connected to the respective electrodes and disposed at positions different from each other with respect to the axial direction of the airtight container.
9. The fluorescent lamp according to any one of items 1 to 8. 10. A lighting device, comprising: a lighting device main body; and the fluorescent lamp according to claim 1 supported by the lighting device main body.