JPH11354078A - Discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desired luminescent characteristic and reduce the area of an electrode installed on the outside surface of a glass bulb by setting the thickness of the wall of the glass bulb of a part on which the electrode is installed to be smaller than that of the wall of other part. SOLUTION: For a glass bulb 21, electrodes 22, 23 formed from an electrically conductive film are separately installed on the peripheral surfaces and outside end surfaces of both their ends and a light-emitting part 26 is formed between electrode installing parts 24, 25. A noble gas or a noble gas and mercury are sealed inside the glass bulb 21, and a phosphor layer is formed on its inside circumferential surface. The thickness of the wall of the electrode installing parts 24, 25 of the glass bulb 21 is set smaller than that of the wall of the light-emitting part 26. For instance, for a fluorescent discharge lamp 20 of which rated power is 10W, the total length of the glass bulb 21 is set to 200-1,000 mm, its outside diameter to 6.0-30.0 mm, the wall thickness of the electrode installing parts 24, 25 to 0.2-0.5 mm, and the wall thickness of the light-emitting part 26 to 0.5-1.0 mm. Thereby, a large effective luminescent length can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp,
For example, the present invention relates to a discharge lamp used as a backlight of a liquid crystal display device, a light source for a scanner device, an ultraviolet light source, and the like.

[0002]

2. Description of the Related Art FIG. 1 is a sectional view for explaining a conventional external electrode type fluorescent discharge lamp. In the figure, 10 is an external electrode type fluorescent discharge lamp, 11 is a straight tube type glass bulb sealed at both ends, and mercury and a rare gas are sealed inside this glass bulb 11, A fluorescent substance is applied to the surface. The electrodes 12 and 13 are formed of an electrically conductive film, and are disposed on the outer peripheral surface and the outer end surface at both ends of the glass bulb 11. Such a fluorescent discharge lamp 10 has a feature that the life is long because no filament is arranged in the glass bulb 11.

In the above-mentioned fluorescent discharge lamp 10, when a high frequency voltage is applied to the electrodes 12, 13, a discharge phenomenon occurs in the internal space of the glass bulb 11, thereby releasing ultraviolet rays. The light is converted into visible light by the fluorescent substance applied to the inner peripheral surface, and this visible light is emitted to the outside of the glass bulb 11.

Here, the current (hereinafter referred to as “input current”) supplied into the glass bulb 11 of the fluorescent discharge lamp 10 is determined by the dielectric constant of the glass of the glass bulb 11 and the electrode 1.
2 and 13 and the size of the capacitive coupling determined by the thickness of the wall of the glass bulb 11 at the position or region where the electrodes 12 and 13 are disposed. The coupling capacity by capacitive coupling is represented by the following equation (1).

[0005]

Equation (1) C = ε × S / d (where C is the coupling capacity, ε is the dielectric constant of the glass of the glass bulb, S is the electrode area, and d is the wall of the glass bulb at the electrode arrangement position. Is the thickness.)

However, in order for the fluorescent discharge lamp 10 to have sufficient emission characteristics, the magnitude of the coupling capacitance C needs to be equal to or greater than a certain value. 13 must have a sufficient area. However, since the electrodes 12 and 13 cannot transmit light, the effective discharge length L of the fluorescent discharge lamp 10 is shortened.

In order to cope with such a problem, it is conceivable to reduce the area of the electrodes provided on the outer peripheral surfaces at both ends of the glass bulb 11. In this case, the effective light emission of the fluorescent discharge lamp 10 is considered. It is possible to lengthen the length L.
However, as shown in the above equation (1), when the electrode area S decreases, the coupling capacitance C also decreases proportionally,
As a result, the applied current is reduced. As a result, in the internal space of the glass bulb, a sufficient discharge phenomenon is not obtained, and the lamp is not lit, or a discharge phenomenon hardly occurs, and a sufficient light emission amount cannot be obtained even when the lamp is turned on.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a desired light-emitting characteristic and to be provided on the outer surface of a glass bulb. An object of the present invention is to provide a discharge lamp capable of reducing the area of an electrode.

[0009]

DISCLOSURE OF THE INVENTION The discharge lamp of the present invention comprises:
At least one end has a glass bulb on which an electrode is disposed on an outer surface, and a wall of the glass bulb on which the electrode is disposed (hereinafter, referred to as an “electrode disposed portion”) has a wall thickness. It is characterized in that it is smaller than the thickness of the wall of the other part.

[0010]

Embodiments of the present invention will be described below in detail. FIG. 2 is an explanatory sectional view showing an example of the present invention. In this figure, reference numeral 20 denotes a fluorescent discharge lamp, and reference numeral 21 denotes a straight tube-type glass bulb whose both ends are sealed. In the glass bulb 21, electrodes 22 and 23 made of an electrically conductive film are provided on the outer peripheral surface and the outer end surface at both ends.
Is provided, and a light emitting portion 26 is formed between the electrode providing portions 24 and 25. A rare gas or a rare gas and mercury are sealed inside the glass bulb 21, and a phosphor layer is formed on the inner peripheral surface of the glass bulb 21.

Here, as a material constituting the glass bulb 21, for example, Kovar glass, lead glass, borosilicate glass, or the like is preferable. Further, as the rare gas sealed in the glass bulb 21, neon, argon, other rare gases, or a mixed gas thereof is used. Electrode 2
Examples of the material constituting the layers 2 and 23 include a metal tape such as an aluminum tape and a copper tape, or an electrically conductive film such as a metal thin film, a conductive paste, and an indium tin oxide (ITO) film.

In the fluorescent discharge lamp 20, the thickness of the walls of the electrode arrangement portions 24 and 25 of the glass bulb 21 is smaller than the thickness of the wall of the light emission portion 26. More specifically, for example, in a fluorescent discharge lamp 20 having a rated power of 10 W, a glass bulb 21 is provided.
Has a total length of, for example, 200 to 1000 mm and an outer diameter of, for example, 6.0 to 30.0 mm.
The thickness of the 25 wall is, for example, 0.2 to 0.5 mm,
The thickness of the wall of the light emitting portion 26 is, for example, 0.5 to 1.0 mm.
It is said. In addition, the sealed pressure of the rare gas or the rare gas and the mercury inside the glass bulb 21 is, for example, 0.1 to 3
0 kPa.

In the above-mentioned fluorescent discharge lamp 20, when a high frequency voltage is applied to the electrodes 22 and 23, a discharge phenomenon occurs in the internal space of the glass bulb 21 to emit ultraviolet rays. It is converted into visible light by the phosphor layer formed on the inner peripheral surface,
This visible light is emitted to the outside of the glass bulb 21.

In the above fluorescent discharge lamp 20, since the thickness of the walls of the electrode arrangement portions 24 and 25 in the glass bulb 21 is smaller than the thickness of the wall of the light emitting portion 26, the above equation (1) is used.
As is clear, even if the area where the electrodes 22 and 23 are provided is reduced, the coupling capacitance C is sufficiently large. As a result, according to the configuration of the present invention, the area of the electrodes 22 and 23 disposed on the outer peripheral surfaces at both ends of the glass bulb 21 is reduced while maintaining the required input current, so that the effective light emission length L is increased. Can be obtained.

From the above, the above-described fluorescent discharge lamp 2
At 0, the following effects can be actually obtained. When the overall length and outer diameter of the fluorescent discharge lamp 20 are fixed, the areas of the electrodes 22 and 23 provided on the outer peripheral surfaces at both ends of the glass bulb 21 are reduced, and the electrodes 22 and 2 are reduced.
Since the length R can be shortened, a long effective emission length L can be obtained. When the effective emission length L and the outer diameter of the fluorescent discharge lamp 20 are determined, the length R of the electrodes 22 and 23 disposed on the outer peripheral surfaces at both ends of the glass bulb 21 can be shortened. The overall length of the fluorescent discharge lamp 20 can be reduced. Further, when the outer diameter of the fluorescent discharge lamp 20 is fixed, it is possible to obtain a long effective emission length L while shortening the overall length of the fluorescent discharge lamp 20.

In addition, the fluorescent lamp 20 of the illustrated example is easy to handle because the outer diameter of the glass bulb 21 is constant over the entire length. For example, when a plurality of such fluorescent lamps 20 are arranged and used in parallel. Also, the fluorescent discharge lamps 20 can be densely arranged, and light with a large emission density can be obtained.

Although an example of the discharge lamp of the present invention has been described above, the present invention is not limited to this, and for example, the following modifications are possible. (1) In the fluorescent discharge lamp 20 shown in FIG.
Although the electrodes 2 and 23 are disposed on the outer peripheral surface and the outer end surface of both ends of the glass bulb 21, either one of the electrodes may be disposed inside the glass bulb 21. According to such a configuration, the area of the electrode can be reduced with only one of the electrodes, so that the overall length of the discharge lamp can be reduced or the effective emission length can be increased.

(2) As shown in FIG.
1, the diameter of the electrode arrangement portions 34 and 35 is
The discharge lamp 30 may be formed to be larger than the diameter of the discharge lamp 30. According to such a configuration, the glass bulb 31
Length R of the electrodes 32 and 33 disposed on the outer peripheral surfaces of both ends of the
Can be further shortened, so that the discharge lamp 30
Can be shortened, or the effective light emission length L can be increased. Further, in the discharge lamp 30, since the thickness of the walls of the electrode disposing portions 34 and 35 is smaller than the thickness of the wall of the light emitting portion 36, the electrode disposing portions are compared with the case where they are not so. The diameters of 34 and 35 can be suppressed small.

[0019]

EXAMPLES The present invention will now be described by way of specific examples, which should not be construed as limiting the invention thereto. <Example 1> According to the configuration of FIG.
Lighting by applying a high frequency voltage of kHz [Lighting conditions (applied voltage to electrode: 800 Vrms, current: 20 m)
Arms)] to produce a fluorescent discharge lamp having a rated power of 10 W. [Glass bulb] Material: Kovar glass Dimensions: Total length 300 mm, outer diameter 8.0 mm Electrode disposing part: inner diameter 7.65 mm, total length 200 mm Light emitting part: inner diameter 7.5 mm, total length 50 mm [Electrode] Material: aluminum, thickness: 50 μm Length of electrode disposition part: 50 mm [Phosphor layer] Material: Three-wavelength phosphor, thickness: 15 μm [Enclosure] Enclosure gas: Mixed gas of neon and argon (composition ratio: Neon / argon = 90 mol) % / 10 mol%) Filling pressure: 5.3 kPa (40 Torr) Mercury: Filling amount 4 mg

For comparison, a discharge lamp was manufactured in which the thickness of the wall of the electrode-arranged portion in the glass bulb was uniform with the thickness of the wall of the light-emitting portion. For this purpose, the length of the electrode had to be 70 mm. For this reason, it was necessary to increase the length of the electrode by 40 mm.

[0021]

As described above, according to the present invention,
It is possible to provide a discharge lamp capable of obtaining desired light emission characteristics and reducing the area of an electrode provided on the outer surface of a glass bulb.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing a conventional fluorescent discharge lamp.

FIG. 2 is an explanatory sectional view showing an example of the present invention.

FIG. 3 is an explanatory sectional view showing a modification of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fluorescent discharge lamp 11 Glass bulb 12, 13 electrode 20 Fluorescent discharge lamp 21 Glass bulb 22, 23 electrode 24, 25 Electrode installation part 26 Light emission part L Effective light emission length R Length of electrode installation part

Claims (1)

[Claims] 1. A discharge lamp comprising a glass bulb having an electrode disposed on at least one end of an outer surface thereof, wherein the thickness of the wall of the glass bulb at the portion where the electrode is disposed is the same as that of the other portion. A discharge lamp characterized by being smaller than a wall thickness.