JPH11213950A - Low pressure gas discharge lamp and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low pressure gas discharge lamp developing a stabilized positive column, generating no flickering in brightness, and suppressing brightness drop caused by the loss of a noble gas, and a lighting system using this low pressure gas discharge lamp. SOLUTION: A pair of electrodes is sealed at both ends of a slender light transmissive airtight container 1, a noble gas is sealed on the inside, a γ alumina layer 5 is formed on the inner surface of the light transmissive airtight container, and a conductive material strap is formed on the outer surface along the discharge route between the electrodes. A phosphor layer 6 is formed on the inner surface of the light transmissive airtight container 1, xenon as the noble gas is sealed, ultraviolet rays are generated by discharge, the phosphor layer 6 is excited with the ultraviolet rays to obtain expected visible light. Since the γ alumina layer 5 is formed in a dense film, the invasion of noble gas ions from a positive column drawn to the conductive material strap into the light transmissive airtight container 1 is suppressed, the positive column is stabilized, the generation of the flickering of brightness is prevented, the loss of the noble gas is prevented to reduce the brightness drop during the service life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-pressure gas discharge lamp filled with a rare gas and a lighting device using the same.

[0002]

2. Description of the Related Art In a so-called backlight for illuminating various instruments arranged on an instrument panel of an automobile from the back, a small incandescent light bulb is generally used. In the description, a bent small fluorescent lamp is used. By using such a fluorescent lamp, power can be saved, and the luminance of the panel surface can be increased to significantly improve the visibility.

[0003] However, this kind of conventional fluorescent lamp generates ultraviolet rays by utilizing low-pressure vapor discharge of mercury,
In this configuration, the phosphor layer is excited by ultraviolet rays to emit visible light.

However, since the mercury vapor pressure greatly changes under the influence of the ambient temperature, this kind of fluorescent lamp has a problem that the luminous flux at a low temperature is insufficient.

[0005] For this reason, ancillary equipment such as increasing the mercury vapor pressure by heating the fluorescent lamp at a low temperature by adding a heater to the fluorescent lamp is required, which is inevitably expensive, and is a factor inhibiting the spread. Has become.

It is not preferable to use mercury which has a large environmental load.

Accordingly, the present inventors have conceived of generating ultraviolet rays using a low-pressure gas discharge of a rare gas such as xenon instead of mercury, and causing the phosphor layer to emit visible light. The low-pressure gas discharge of the rare gas is not easily affected by the ambient temperature, so there is no problem as in the prior art, but it is difficult to obtain a sufficient luminous flux.

[0008] It has been found that when the rare gas sealing pressure is increased for the purpose of increasing the luminous flux and prolonging the service life, there is a problem that the positive column shrinks, snaking occurs, and the brightness flickers.

As a result of further research, the present inventors have completed an invention for stabilizing the positive column, and the present invention is disclosed in Japanese Patent Application No. 9-2980.
No. 55704. The outline is as follows.

That is, the low-pressure gas discharge lamp satisfies Equation 1 when the sealed pressure of the rare gas at normal temperature is p (torr) and the molecular radius of the rare gas is r _g (Å), It is assumed that the inner diameter 2r of the container satisfies Equation 2.

[0011]

[Equation 1] r _g ² × p ≧ 100

[0012]

2r ≦ 5 mm In the above application, an auxiliary electrode is formed along the discharge path on the outer surface of the light-transmitting airtight container, and the positive column is attracted to the inner wall of the light-transmitting airtight container and stabilized. It is also disclosed.

[0013]

However, by forming a conductive material strip along the discharge path on the outer surface of the light-transmitting airtight container, the positive column is attracted to the conductive material strip, thereby stabilizing the positive column. Can reduce the flicker of brightness, but the positive ions of the rare gas enter the surface of the translucent airtight container and disappear in a relatively short period of time. It has been found that there is a problem of causing a flicker of brightness due to the thermal contraction. In particular, this problem tends to be remarkable during dimming lighting.

The present inventor has finally completed the present invention as a result of various studies and trial production.

According to the present invention, the stability of the positive column is obtained, and the brightness does not flicker. In addition, the positive column is prevented from being partially shrunk due to disappearance of rare gas ions, and the brightness flicker during dimming is reduced. It is an object of the present invention to provide a low-pressure gas discharge lamp with a reduced number and a lighting device using the same.

[0016]

A low-pressure gas discharge lamp according to the present invention comprises an elongated light-tight hermetic container; a gamma-alumina layer formed on an inner surface of the light-transmitting hermetic container; A pair of electrodes sealed at both ends of the light-transmitting hermetic container; a rare gas sealed inside the light-transmitting hermetic container; and a conductive material strip formed on the outer surface of the light-transmitting hermetic container along a discharge path between the electrodes. And;

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

[0018] The "translucent airtight container" means that at least a required portion is translucent and a discharge medium is enclosed therein to discharge radiation generated by the low-pressure gas discharge to the outside. A material having airtightness and heat resistance that can withstand the heat generated. However, the material is not limited, and for example, glass, ceramics, or the like can be used. Further, the glass may be any of hard glass, semi-hard glass and soft glass, and if necessary, quartz glass can be used.

An "elongated translucent airtight container" is defined as having an inner diameter of 2 mm.
It has a length twice or more.

The shape of the light-transmitting airtight container may be either a straight tube or a non-linear shape. The non-linear shape refers to a shape that is not a straight tube, such as an annular shape, a C shape, a U shape, an L shape, or a shape similar thereto.

The γ-alumina layer can be formed by, for example, applying a suspension of fine particles of γ-alumina to the inner surface of a light-transmitting container, drying and firing. Γ also by CVD method etc.
An alumina layer can be formed. The thickness of the γ-alumina layer is effectively in the range of 0.1 to 10 μm.

Since the electrodes can be easily miniaturized, cold cathodes are often used in small low-pressure gas discharge lamps, but hot cathodes may be used if necessary.

As the rare gas, one or more of neon, argon, krypton, and xenon can be mainly used. In particular, xenon generates ultraviolet rays by low-pressure gas discharge, and is suitable for exciting the phosphor layer with the ultraviolet rays to emit desired visible light. However, in the present invention, if desired, the radiation from the low-pressure rare gas discharge may be directly extracted to the outside as visible light or ultraviolet light.

In the present invention, the relationship between the inner diameter of the translucent airtight container and the rare gas to be filled can be as follows, as in the case of the earlier patent application. That is, the low-pressure gas discharge lamp sets the noble gas charging pressure at room temperature to p.
(Torr), when the molecular radius of the rare gas is r _g (Å), it is assumed that Equation 1 is satisfied and the inner diameter 2r of the light-transmitting airtight container satisfies Equation 2.

[0025]

[Equation 1] r _g ² × p ≧ 100

[0026]

2r ≦ 5 mm Table 1 shows the atomic radii (Å) and the sealing pressure (torr) (lower limit) of main rare gases. The atomic radii were quoted from "New Physical Properties Table" (published by Asakura Shoten).

[0027]

Table 1 Noble gas Neon Argon Krypton Xenon Atomic radius (Å) 1.17 1.43 1.59 1.75 Filling pressure (torr) 65 40 30 30 In the low-pressure gas discharge lamp manufactured in the above relationship, the sunlight The radius of the pillar becomes about 2 to 3 mm.

The term "conductive material strip" means a linear or band-shaped elongated conductive material, which can be formed of a conductive metal, a conductive synthetic resin, a conductive rubber, or the like. Forming a conductive metal such as aluminum, copper or silver foil directly on the outer surface of the transparent airtight container,
A transparent or opaque synthetic resin film is used as a substrate, a metal foil is formed on the transparent resin film by vapor deposition or the like, and the synthetic resin film is adhered to the translucent airtight container to form a conductive material strip on the outer surface of the translucent airtight container. Can be formed. The conductive synthetic resin and the conductive rubber can be obtained from a mixture of a synthetic resin and a rubber and a powder of metal or carbon, or a synthetic resin or a rubber containing a conductive substance as a part of the composition. In the case of the conductive synthetic resin and the conductive rubber, it is easy to directly adhere the outer surface of the light-transmitting airtight container.

The positions where the conductive material strips are formed on the outer surface of the light-transmitting airtight container are as follows. That is, when the light-transmitting airtight container is a straight tube, it may be formed linearly along the discharge path between the electrodes at an arbitrary position on the outer periphery of the light-transmitting airtight container. When the light-transmitting airtight container has a non-linear shape, it is effective to form the outer surface of the light-transmitting airtight container at the shortest distance between the electrodes or in the vicinity thereof. In addition,
The phrase “the conductive material strip is in the vicinity of the shortest distance between the electrodes” means that it is located on the shortest distance side from an intermediate point between the shortest distance and the longest distance. Further, both ends of the conductive material strip are opposed to the electrodes at both ends of the airtight container or are located near the electrodes.

The conductive material strip can be formed so as to be electrically connected to one of the electrodes, if desired. However, it may not be connected to the electrode. That is, when the low-pressure gas discharge lamp of the present invention is turned on, a conductive material strip may be connected to the low-pressure gas discharge lamp by external wiring, and if necessary, the conductive material strip may be connected to a different potential from both electrodes. It can be connected to a potential source including a ground potential, and even if it is not connected to any potential source, the floating capacitance formed between the positive column and the conductive material strip Thereby, the positive column can be attracted by the conductive material strip.

According to the present invention, since the γ-alumina layer is formed on the inner surface of the light-transmitting airtight container as described above, the γ-alumina layer has a positive contact charge amount, so that the positive column becomes conductive. When the rare gas ions are attracted to the conductive material strip and approach the inner surface of the light-transmitting airtight container, the rare gas ions can be prevented from entering the surface of the airtight container and disappearing. Thereby, it is possible to prevent the positive column from partially shrinking at the time of dimming to cause a flicker in brightness. Although the mechanism is not always clear, it is considered that this is because the positive column can maintain a certain extent by the γ-alumina layer. Of course, when the positive column is attracted to the conductive material strip, the positive column is stabilized, and the brightness does not flicker.

The low pressure gas discharge lamp according to the second aspect of the present invention
2. The low-pressure gas discharge lamp according to claim 1, wherein the rare gas is xenon; the rare gas is formed on the inner surface side of the transparent airtight container, and emits visible light when excited by ultraviolet rays generated by the low-pressure discharge of the rare gas. And a phosphor layer having the following characteristics:

In the present invention, the phrase “the phosphor layer is formed on the inner surface side of the translucent airtight container” means that the phosphor layer is formed directly on the inner surface of the translucent airtight container. This means that any layer is interposed between the light-tight container and the phosphor layer.

Thus, in the present invention, a phosphor layer which emits visible light when excited by the ultraviolet rays by generating ultraviolet rays by low pressure gas discharge of xenon using xenon as a rare gas is provided. Thereby, visible light having a desired light color and color rendering properties can be obtained.

For this reason, the low-pressure gas discharge lamp of the present invention can be replaced with a conventional fluorescent lamp filled with mercury.

The low-pressure gas discharge lamp according to the third aspect of the present invention
The low-pressure gas discharge lamp according to claim 1 or 2,
The conductive material strip is made of a metal foil and is formed on the outer surface of the light-transmitting airtight container by bonding.

The metal foil may be adhered directly to the outer surface of the translucent airtight container, or may be adhered to the translucent airtight container via an appropriate substrate. As the substrate, a transparent synthetic resin sheet such as a transparent polyester sheet can be used.

The adhesion of the metal foil to the translucent airtight container may be carried out by using a tacky adhesive which has been applied to the back surface of the metal foil or the substrate in advance.

Thus, in the present invention, the conductive material strip can be made thin by bonding the metal foil to form the conductive material strip. The material strip is less likely to get in the way.

By using a metal having a high light reflectance, for example, a metal such as silver or aluminum, a conductive material strip can be used as a reflector.

According to a fourth aspect of the present invention, there is provided a lighting device comprising: a lighting device main body; and the low-pressure gas discharge lamp according to any one of the first to third aspects provided in the lighting device main body. Features.

In the present invention, the illumination device is a concept including any device that uses the light emission of the low-pressure gas discharge lamp for some illumination purpose. An example of a lighting device is as follows. That is, there are backlights and various devices incorporating the backlights, such as instrument panels for automobiles, lighting equipment, display devices, and the like.

[0043]

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

FIG. 1 is a front view showing a first embodiment of the low-pressure gas discharge lamp of the present invention.

FIG. 2 is an enlarged end view.

In the figure, 1 is a translucent airtight container, 2 is an electrode, 3 is a lead wire, 4 is a conductive material, 5 is a γ-alumina layer, and 6 is a phosphor layer.

The translucent airtight container 1 is made of borosilicate glass (semi-hard glass), has an outer diameter of 3 mm, an inner diameter of 2 mm, and an effective length of 500 mm, and has a deformed annular non-linear shape as shown in FIG. It is curved.

The electrode 2 is a cold cathode made of a nickel tube,
Sealed at both ends of the translucent airtight container 1.

The introduction wire 3 penetrates both ends of the translucent airtight container 1 in a gas-tight manner to support the electrode 2 at the inner end thereof.
A current is supplied to the electrode 2 from outside.

The conductive material strip 4 is made of an aluminum foil having a width of 1 mm and is adhered to the inner surface of the deformed annular shape. The ends of the conductive material strips 4 are located at positions facing the electrodes 2 respectively.

As shown in FIG. 2, the γ-alumina layer 5 has a thickness of about 0.5 over almost the entire inner surface of the light-transmitting airtight container 1.
μm.

The phosphor layer 6 is made of a phosphor of a three-wavelength emission type, and is formed on the inner surface of the γ-alumina layer 5 to a thickness of about 20 μm. The phosphor emits visible light when excited by irradiation with ultraviolet light generated by a low-pressure gas discharge of xenon.

About 80 xenon is contained in the translucent airtight container 1.
A low-pressure gas discharge lamp is formed by tor sealing.

Then, a low-pressure gas discharge lamp of this embodiment and a comparative lamp having the same specifications as those of this embodiment except that the γ-alumina layer is not formed were manufactured, and the output terminal of the high-frequency inverter was connected to a pair of electrodes. 2 and 2, and one end of the conductive material strip 4 is connected to one of the electrodes.
The lamp was lit 100% at 100 kHz, and the light was lit at a frequency of 100 kHz. As a result, in both the present embodiment and the comparative lamp, the positive column was attracted to the conductive material strip 4 and was sufficiently stable, and no flickering of brightness occurred.

FIG. 3 is a front view showing a second embodiment of the low-pressure gas discharge lamp of the present invention.

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

This embodiment is different in that the conductive material strip 4 is formed near the shortest distance between the electrodes.

That is, the conductive material strip 4 is located on the shortest distance side from the midpoint between the shortest distance and the longest distance between the electrodes. Other configurations are the same as those of the first embodiment shown in FIG.

Thus, also in the present embodiment, the positive column is sufficiently attracted to the conductive material strip 4 and is stable even at the time of dimming, so that the brightness does not flicker.

The decrease in luminance during the life was almost the same as in the first embodiment.

FIG. 4 is a front view showing a display panel in an automotive instrument panel as one embodiment of the lighting device of the present invention.

In the figure, reference numeral 11 denotes a display panel, from the left, a fuel gauge indicating section 11a, a speedometer indicating section 11b,
The tachometer indicating unit 11c and the water temperature meter indicating unit 11d are illustrated. In actuality, in addition to the above, a light emitting display unit for various displays and warnings is provided.

The display panel 11 is provided with each meter indicating section 11
The portions a, 11b, 11c and 11d are formed to be translucent, while the ground portion is formed to be light-shielding. Reference numeral 12 denotes a rotating shaft, and reference numeral 13 denotes a pointer, which are disposed at the positions shown in the figure in an assembled state of the instrument panel.

FIG. 5 is a front view showing a reflection panel in an automotive instrument panel according to an embodiment of the present invention.

FIG. 6 is a sectional view taken along the line VI-VI 'of FIG.

In each of the figures, reference numeral 13 denotes a reflection panel, which is disposed behind the display panel 11.
Reflection surfaces 13a, 13b, 13c and 13d are formed in portions facing 1a, 11b, 11c and 11d. 13e is a lamp holder, 13f is a meter mounting part.

Each of the reflecting surfaces 13a, 13b, 13c and 1
As shown in FIG. 6, 3d is formed in the concave portion of the reflection panel, and is radiated from the gas discharge lamp surrounding the low-pressure gas discharge lamp (not shown) housed in each concave portion. The light incident on the reflecting surface is reflected by the reflecting surface, and the opposite meter indicating portions 11a and 11 of the display panel 11 are provided.
b, 11c and 11d.

The lamp holder 13e is made of metal grounded to the vehicle body, supports the gas discharge lamp, and is electrically connected to the conductive material strip to ground the conductive material strip. Note that one electrode of the gas discharge lamp is also grounded. Further, although not shown, the gas discharge lamp is given a length such that the light emitting portion of the airtight container has a shape substantially equal to the contour of each meter indicating portion, and is formed in a curved and non-linear shape. . That is, a low-pressure gas discharge lamp having a 1/4 arc shape is used for a fuel gauge and a water temperature meter, and a low-pressure gas discharge lamp having a modified annular shape as shown in FIG. 1 is used for a speedometer and a tachometer. .

[0069]

According to the first to third aspects of the present invention, the conductive material is formed along the discharge path between a pair of electrodes sealed at both ends of the light-transmitting airtight container on the outer surface of the elongated light-transmitting airtight container. And a γ on the inner surface of the translucent airtight container.
The formation of the alumina layer can effectively prevent rare gas ions from entering the inner surface of the light-transmitting hermetic container when the positive column is attracted to the conductive material strip, thereby controlling light. It is possible to provide a low-pressure gas discharge lamp in which the positive column is sometimes partially shrunk to cause a flicker in brightness and the positive column is stabilized to prevent flicker in brightness.

According to the second aspect of the present invention, in addition, the rare gas is xenon, and the phosphor layer which emits visible light with ultraviolet rays generated by the discharge of xenon is provided on the inner surface side of the transparent airtight container. Thus, a low-pressure gas discharge lamp for obtaining desired visible light can be provided.

According to the third aspect of the present invention, the conductive material strip is made of metal foil and formed on the outer surface of the light-transmitting hermetic container by bonding, so that the conductive material strip is thinned and the lighting device is made thin. It is possible to provide a low-pressure gas discharge lamp that is easy to assemble.

According to the fourth aspect of the present invention, it is possible to provide a lighting device having the effects of the first to third aspects.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of a low-pressure gas discharge lamp of the present invention.

FIG. 2 is an enlarged end view of the same.

FIG. 3 is a front view showing a second embodiment of the low-pressure gas discharge lamp of the present invention.

FIG. 4 is a front view showing a display panel in an instrument panel for a vehicle as one embodiment of the lighting device of the present invention.

FIG. 5 is a front view showing a reflection panel in an automotive instrument panel as one embodiment of the lighting device of the present invention.

FIG. 6 is a sectional view taken along the line VI-VI ′ of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Translucent airtight container 2 ... Electrode 3 ... Introductory wire 4 ... Conductive material strip 5 ... Gamma alumina layer 6 ... Phosphor layer

Claims (4)

[Claims] An elongated light-transmitting airtight container; a gamma-alumina layer formed on an inner surface of the light-transmitting airtight container; a pair of electrodes sealed at both ends of the light-transmitting airtight container; A low-pressure gas discharge lamp, comprising: a rare gas sealed inside the container; and a conductive material strip formed along a discharge path between the electrodes on an outer surface of the light-transmitting hermetic container. 2. A rare gas is xenon; and a phosphor layer formed on the inner surface side of the light-transmitting hermetic container and emitting visible light when excited by ultraviolet light generated by a low-pressure discharge of the rare gas. The low-pressure gas discharge lamp according to claim 1, wherein: 3. The low-pressure gas discharge lamp according to claim 1, wherein the conductive material strip is made of a metal foil and is formed on the outer surface of the translucent airtight container by bonding. 4. A lighting device comprising: a lighting device main body; and the low-pressure gas discharge lamp according to claim 1 disposed in the lighting device main body.