JP2001210276A - Fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a xenon gas contained fluorescent lamp which has directivity and lights in a low current zone. SOLUTION: The fluorescent lamp comprises a tubular glass bulb 1 filled with a discharge rare gas, an internal electrode 3 sealed in the glass bulb 1 and a fluorescent material 2 applied on the inner face of the glass bulb 1 whose outer face is provided with an external electrode 5 formed of a conductive member and a reflective sheet 7 formed of an insulating material for giving directivity to the lamp. The diffusion area of the external electrode 5 with respect to the outer face of the glass bulb 1 is 20% or less of the surface area of the glass bulb 1, and the visible light reflectivity of the reflecting sheet 7 is 50% or more and the area opposed to the outer face of the glass bulb is 50% or more of the surface area of the glass bulb 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is based on xenon, in which one electrode is provided outside a discharge chamber as an external electrode and the other electrode is provided inside the discharge chamber, and performs a barrier discharge through a dielectric glass bulb. More specifically, the present invention relates to a fluorescent lamp having directivity and improved so as to spread light emission over the entire bulb in a low tube current range.

[0002]

2. Description of the Related Art Conventionally, there have been known fluorescent lamps of this kind as disclosed in JP-A-11-25923 and JP-A-5-29085, which will be described with reference to FIGS. I do. A phosphor 2 is attached to the inner surface of a straight tubular glass bulb 1, and an internal electrode 3 made of a cold cathode is sealed inside the end, and a lead wire 4 connected to the internal electrode 3 is connected to the glass bulb 1. It penetrates the end wall airtightly and is led out. A strip-shaped external electrode 10 made of a conductive metal such as an aluminum tape is adhered to the outer surface of the glass bulb 1 along the bulb axis. One surface of the external electrode 10 has an adhesive layer having an adhesive or adhesive function, is provided at an angle of 180 ° or more in the circumferential direction around the axis of the glass bulb 1, and emits visible light on the inner surface of the external electrode 10. The light is reflected, condensed at an opening where the external electrode 10 is not provided, and emitted to the outside, so that the fluorescent lamp has directivity. In other words, since the structure is such that visible light is reflected by the inner surface of the external electrode and light is emitted from the portion where the external electrode is not formed, the directional lamp has a high luminance in one direction, and the backlight can have high luminance. There are advantages.

[0003]

However, when the conventional fluorescent lamp is lit with a low tube current, the light emission does not spread over the entire bulb and partial discharge occurs on the internal electrode side. If you try to spread the light emitting part over the entire bulb,
Due to the high tube current required, first, the power consumption of the lamp is high, second, the tube wall temperature is high, and third, the sputtering of the internal electrode is severe, and the operating life is short. was there. In order to solve these problems, it is necessary to spread light emission in the entire bulb axial direction in a low tube current region.

The inventor of the present invention believes that the tube voltage when the light emission spreads over the entire lamp is substantially constant regardless of the area of the external electrode. Focusing on the fact that the lamp can be turned on with low tube power, the present inventors have invented the present invention. In other words, the directivity of the lamp is reduced by reducing the area of the external electrode and thereby losing the directivity of the lamp due to the reduction of the light reflection area by providing an insulating reflective sheet that does not contribute to the discharge on the outer surface of the glass bulb. An object of the present invention is to provide a xenon gas-containing fluorescent lamp that has a function of lighting in a low current range.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a rare gas for discharge is sealed in a tubular glass bulb, and an internal electrode is provided inside the glass bulb. And a fluorescent substance is adhered to the inner surface of the glass bulb, and an outer electrode made of a conductive member is formed on the outer surface of the glass bulb, and an insulating material for giving directivity to the lamp is formed of a material having an insulating property. In a fluorescent lamp provided with a reflection sheet, the external electrode has a diffusion area with the outer surface of the glass bulb of 20% or less of the surface area of the glass bulb, and the reflection sheet has a visible light reflectance of 50% or more. In addition, the area facing the outer surface of the glass bulb is 50% or more of the surface area of the glass bulb.

In the invention according to claim 2 of the present invention, the discharge rare gas is xenon or an inert gas mainly composed of xenon.

In the invention according to claim 3 of the present invention, the external electrode is formed by spirally winding a conductive metal wire along the bulb axis to reduce the area facing the glass bulb. Solve the problem.

In the invention according to claim 4 of the present invention, the external electrode is a strip-shaped external electrode made of a conductive material, and is provided along the valve axis.

In the invention according to a fifth aspect of the present invention, the phosphor is removed at a position corresponding to a portion of the inner surface of the glass bulb where the reflection sheet is not provided. I do.

[0010] In the invention according to claim 6 of the present invention, at a position corresponding to a portion where the reflection sheet is not provided on the inner surface of the glass bulb, the phosphor at the portion where the reflection sheet is provided is provided. The thickness of the phosphor layer is smaller than that of the layer.

In the present invention, the outer surface of the lamp is covered with a heat-shrinkable protective tube to improve the quality of the fluorescent lamp.

[0012]

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

FIG. 1 is a front sectional view showing a main part of a fluorescent lamp, and FIG. 2 is a longitudinal sectional view. In these figures, reference numeral 1 in the figures denotes a straight tubular transparent glass bulb, both ends of which are hermetically closed, and a phosphor 2 such as a rare earth phosphor is adhered to the inner surface thereof. The inside of the glass bulb 1 is sealed at a predetermined sealing pressure using xenon (Xe) as a discharge medium, but is preferably sealed at a pressure of, for example, 20 to 200 Torr. The rare gas as the discharge medium is a single gas of xenon, or xenon is mainly composed of argon,
Any gas mixture of neon, krypton and the like may be used.

An internal electrode 3 made of a cold cathode is sealed inside one end of the glass bulb 1, and a lead wire 4 electrically connected to the internal electrode 3 seals an end wall of the glass bulb 1. Through to the outside.

On the outer surface of the glass bulb 1, a metal wire made of a highly conductive material such as a nickel wire aluminum wire, a copper wire, a silver wire or the like is spirally wound and attached to form an external electrode 5. . The external electrode 5 is wound in a spiral shape having a predetermined pitch along the bulb axis direction over substantially the same length as the portion of the outer peripheral surface of the glass bulb 1 on which the phosphor 2 is formed. Although it is attached by rotation, the contact area of the external electrode 5 with the surface of the glass bulb 1 must be 20% or less of the surface area of the glass bulb 1. This value is derived experimentally and is a value when the tube power consumption at the time of lighting is about half or less of that of the conventional fluorescent lamp. That is, the ratio of the contact area of the external electrode with the bulb to the bulb surface area is 10% within the range of 10 to 70%.
For the xenon-containing fluorescent lamps, which were different every time, the minimum tube power when the light emission spreads over the entire bulb (at the time of lighting) was measured.
This value specifies a value when light emission spreads over the entire tube with a tube power of about half or less of a conventional fluorescent lamp of 0%. The result is as shown in FIG.

The internal electrode 3 and the external electrode 5 are connected to a lead wire 4,
6 is connected to a power supply (not shown).

On the outer peripheral surface of the glass bulb 1, a band-shaped reflection sheet 7 for reflecting visible light is provided over the light emitting portion along the bulb axis direction. The reflection sheet 7 has a reflectance of visible light of 50% or more, is made of a non-conductive substance having an insulating property, for example, a mixture of aluminum oxide and titanium oxide, and has a contact area of the reflection sheet 7 with the glass bulb 1. Is preferably 50% or more of the surface area of the glass bulb 1. When the area of the external electrode 5 is reduced as compared with the conventional fluorescent lamp as in this embodiment, the amount of light reflected by the external electrode 5 decreases, and the external electrode shown in the above-described conventional example has a glass bulb surface area. The directivity of the lamp is remarkably lost as compared with a fluorescent lamp having a size of about 50%. Therefore, in order to reduce the area of the external electrode and to make the lamp have directivity, the area of the reflection sheet 7 provided on the outer surface of the glass bulb 1 is 50% of the surface area of the glass bulb 1.
%.

Further, a protective tube 8 made of a transparent heat-shrinkable resin is covered on the outer peripheral surface of the glass bulb 1.
The protective tube 8 is excellent in heat resistance such as fluororesin and polyethylene, and has translucency. After being attached to the glass bulb 1, the protective tube 8 is heated to, for example, 100 ° C. or more and shrunk, so that the reflective sheet 7 and The external electrode 5 is tightly fixed to the glass bulb 1. Protection tube 8
, The quality of the fluorescent lamp is improved.

Next, the operation will be described. When a voltage is applied between the internal electrode 3 and the external electrode 5 from a power supply (not shown), a voltage is applied to the xenon gas in the glass bulb 1 through the dielectric glass to generate a discharge. The xenon gas is ionized and excited to emit ultraviolet light, which is converted into visible light by the phosphor 2 and radiated to the outside through the glass bulb 1. When the reflectance of the reflection sheet 7 is 50% or more, Therefore, most of the visible light is radiated outside from the portion where the reflection sheet 7 is not provided, that is, from the opening 9.

Since the tube voltage when light emission is spread over the entire glass bulb (during lighting) is substantially constant irrespective of the area of the external electrode, the tube current when light emission spreads over the entire glass bulb can be reduced. The fluorescent lamp can be turned on with low tube power. In barrier discharge through glass, the derivative glass functions as a capacitor ballast,
If the area of the external electrode is reduced, light emission spreads over the entire bulb with a low tube current (tube power). The light emission of the external electrode having a small area spreads over the entire bulb due to a low tube current, but the light reflection effect by the inner surface of the external electrode is drastically reduced, and the directivity of the lamp is lost. Therefore, the visible light is reflected by the reflection sheet 7 to the inside of the bulb, and the light is projected to the outside from the opening 9 where the reflection sheet 7 is not provided, thereby giving the fluorescent lamp directivity.

Referring to FIG. 4, another embodiment of the present invention will be described. A strip-shaped reflection sheet 7 is provided on the outer peripheral surface of the glass bulb 1 along the bulb axis direction. External electrodes 5 made of a metal wire are spirally wound along the bulb axis direction at an uneven pitch so that the reflection sheet 7 is wound around the outer peripheral surface of the glass bulb 1. Further, the external electrode 5 and the reflection sheet 7 are fixed to the glass bulb 1 by the protective tube 8. The other configuration is completely the same as the embodiment shown in FIGS. 1 and 2 described above.

Referring to FIGS. 5 and 6, another embodiment of the present invention will be described. On the outer surface of the glass bulb 1, a strip-shaped external electrode 10 made of a metal having excellent conductivity such as aluminum or silver is provided along the bulb axis. The area of the external electrode 10 is 20% of the surface area of the glass bulb 1
It is as follows. An external electrode 10 is provided on the outer surface of the glass bulb 1.
Is provided between the glass bulb 1 and the reflection sheet 7, and a protective tube 8 is further covered. The reflection sheet 7 has a visible light reflectance of 50% or more and an area of 50% or more of the surface area of the glass bulb 1 as in the embodiments of FIGS. 1, 2 and 4 described above.

Referring to FIG. 7, another embodiment of the present invention will be described. No phosphor is attached to the portion where the reflection sheet 7 is not formed, that is, the inner surface of the glass bulb 1 corresponding to the opening 9. On the inner surface of the glass bulb 1 corresponding to the opening 9, a phosphor layer thinner than other portions of the phosphor layer may be provided. On the outer surface of the reflection sheet 7, a strip-shaped external electrode 10 having an area of 20% or less of the surface area of the glass bulb 1 is provided along the bulb axis so as to be sandwiched between the reflection sheet 7 and the protection tube 8. ing.
The reflection sheet 7 has a visible light reflectance of 50% or more and an area of 50% or more of the surface area of the glass bulb 1 as in the embodiments shown in FIGS. 1 and 2 and FIGS.

In the embodiments described below, the external electrode may be one in which a metal wire is spirally provided on the outer surface of the glass bulb along the bulb axis, or one in which the strip electrode is provided along the bulb axis. Although described in the example, the shape of the external electrode is not limited to these, and the shape may be any shape as long as the area facing the glass bulb is 20% or less with respect to the surface of the glass bulb. The material is not limited as long as the metal has. Further, the reflecting sheet must have insulating properties, have a visible light reflectance of 50% or more, and have an area of 50% or more with respect to the surface area of the glass bulb. Shapes are included in the present invention. Further, the method of fixing the external electrode and the reflection sheet to the glass bulb is not limited to the method of covering with a heat-shrinkable protective tube and sandwiching and fixing it between the glass bulb and any other method such as sticking. Means are included in the present invention.

The material and shape of the glass tube, the material and shape of the internal electrode, and the presence or absence of an emitter material as a constituent material of the internal electrode are not limited. Further, the method for fixing the external electrodes and the connection form with the voltage supply line are not limited.

[0026]

According to the present invention, the tube current can be reduced to less than half of the conventional fluorescent lamp by reducing the area of the external electrode to 20% or less of the surface area of the glass bulb, and the power consumption can be reduced. Lowering the temperature, suppressing sputtering, extending the life of the lamp, and reducing the directivity due to the reduction in the area of the external electrode reduces the insulating reflective sheet to 50% or less of the glass bulb surface area. By providing the fluorescent lamp over the lamp, the lamp has directivity, and it is possible to provide a fluorescent lamp having the same directivity as a conventional product, and having low power consumption, long life, and high brightness.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a main part of a fluorescent lamp.

FIG. 2 is a longitudinal sectional view of the fluorescent lamp of FIG.

FIG. 3 is a graph showing a relationship between a surface area of a glass bulb facing an external electrode with respect to a surface area of the glass bulb and a minimum tube power when light emission spreads over the entire bulb.

FIG. 4 is a front sectional view showing a main part of another embodiment of the fluorescent lamp.

FIG. 5 is a front sectional view showing a main part of another embodiment of the fluorescent lamp.

FIG. 6 is a longitudinal sectional view of FIG.

FIG. 7 is a longitudinal sectional view showing another embodiment of the fluorescent lamp.

FIG. 8 is an explanatory diagram showing a conventional example.

FIG. 9 is a longitudinal sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass bulb 2 Phosphor 3 Internal electrode 5, 10 External electrode 7 Reflection sheet 8 Protective tube

Claims (7)

[Claims] A rare gas for discharge is sealed in a tubular glass bulb, an internal electrode is sealed inside the glass bulb, a phosphor is adhered on an inner surface of the glass bulb, and a phosphor is adhered on an outer surface of the glass bulb. In a fluorescent lamp provided with an external electrode made of a conductive member and a reflective sheet made of an insulating material for giving the lamp directivity, the diffusion area of the external electrode with the outer surface of the glass bulb is increased. The reflective sheet has a visible light reflectance of 50% or more and an area facing the outer surface of the glass bulb is 5% or less of the glass bulb surface area.
A fluorescent lamp characterized by being at least 0%. 2. The fluorescent lamp according to claim 1, wherein the rare gas for discharge is xenon or an inert gas mainly composed of xenon. 3. The fluorescent lamp according to claim 1, wherein the external electrode is formed by spirally winding a conductive metal wire along a bulb axis. 4. The fluorescent lamp according to claim 1, wherein the external electrode is a strip-shaped external electrode made of a conductive material, and is provided along a bulb axis. 5. The phosphor according to claim 1, wherein the fluorescent material is removed at a position corresponding to a portion of the inner surface of the glass bulb where the reflective sheet is not provided. The fluorescent lamp according to 3 or 4. 6. A phosphor layer at a position corresponding to a portion where the reflection sheet is not provided on the inner surface of the glass bulb, and the phosphor layer is thinner than a portion where the reflection sheet is provided. The fluorescent lamp according to claim 1, 2, 3, or 4, wherein: 7. The glass bulb, the external electrode, and the outer surface of the reflection sheet are covered with a protective tube made of a heat-shrinkable resin.
The fluorescent lamp as described.