JP2001093476A - Fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold cathode fluorescent lamp for improving luminous intensity distribution and light output. SOLUTION: A fluorescent lamp comprises a glass tube 6 which has an inner wall having a fluorescent body coating film 7 thereon and seals a discharge medium, an inner electrode 8 which is sealed with a lead terminal 9 being induced out of one side of the glass tube 6, an outer electrode 10 which is formed of a conductive wire that is spirally wound over almost the full length of an outer circumferential area of the glass tube 6 by a uniform pitch in the direction of the tube, and a translucent resin film 11 which wholly covers the outer circumferential area of the glass tube 6 including the outer electrode 10, if necessary. At least a part of the conductive wire which forms the outer electrode 10 is provided so as to match with stopper portions 6a that are formed on the outer circumferential area of the glass tube 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp suitable for a light source for a backlight of a liquid crystal display device used for a personal computer, a word processor, or the like.

[0002]

2. Description of the Related Art With the spread of personal computers and the like, liquid crystal display devices used for personal computers and word processors are required to have high performance and long life. In these configurations, a cold cathode fluorescent lamp (discharge lamp) is generally used as the rear light source, and the performance of the fluorescent lamp used as the rear light source is being improved. Here, a cold cathode fluorescent lamp (discharge lamp) is generally used as a back light source.
Is used. That is, since the cold cathode fluorescent lamp is a rare gas discharge, its features such as brightness and discharge voltage are hardly affected by the ambient temperature and its life is long.

As a cold cathode fluorescent lamp of high performance, a glass tube having a phosphor film formed on an inner wall surface and containing mercury and a rare gas is provided, and a lead terminal is provided at one end of the glass tube. A lead-out sealed internal electrode;
A fluorescent lamp having an external electrode formed of a conductive wire spirally wound at a required pitch on the outer peripheral surface of the glass tube over a substantially entire length in the tube axis direction has been developed.

FIG. 4 is a cross-sectional view showing an example of a configuration of a conventional fluorescent lamp. In FIG. 4, reference numeral 1 denotes a hermetically sealed glass tube functioning as an arc tube, and reference numeral 2 denotes a phosphor coating formed on the inner wall surface of the glass tube 1. Here, the glass tube 1
Is, for example, about 6 to 10 mm in outer diameter and about 100 to 400 mm in length.
A rare gas as a discharge medium, for example, a rare gas mainly composed of xenon gas or a mercury-rare gas system is sealed.

[0005] Reference numeral 3 denotes a lead terminal (introduction wire) 4 at one end of the glass tube 1 and an internal electrode 5 sealed therein.
Reference numeral denotes an external electrode formed of a conductive wire spirally wound on the outer peripheral surface of the glass tube 1 at a required pitch over substantially the entire length in the tube axis direction.

Here, the internal electrode 3 is, for example, a Ni-based cylindrical body having an opening at one end, and an electron emission material film provided on the inner and outer wall surfaces thereof. The lead terminal 4 is, for example, a W-shaped wire or rod-shaped body. One end of the lead terminal 4 is connected to the bottom wall of the cylindrical body by welding, and the other end is hermetically sealed and led to the glass tube 1. Further, the external electrode 5 has, for example, a diameter of 0.1
A Ni wire of about mm is spirally wound at a required pitch over substantially the entire length in the tube axis direction.

In the fluorescent lamp, a required high-frequency voltage is applied to the internal electrode 3 via the lead terminal 4 and the external electrode 5 via the lead terminal (not shown) (for example, 20 to 100 KHz). , Supply voltage of 1-2KV)
Then, the discharge by the electrodes 3 and 5 starts, and the glass tube 1
Emit ultraviolet light within. The ultraviolet light emitted in this way
The phosphor film 2 on the inner wall surface of the glass tube 1 converts the light into visible light and functions as a fluorescent lamp light source.

[0008]

The fluorescent lamp having the above-described structure has the advantages that the luminous efficiency is good and that it is easy to perform stable lighting or the like, but the light distribution unevenness occurs in the tube axis direction or the light output is insufficient. May be invited. That is, the external electrodes 5 spirally wound and arranged on the outer peripheral surface of the glass tube 1 are exposed to an external impact or force, for example, during transportation or transportation, or when incorporated in a liquid crystal display device. (1) There is a problem that the Ni wire spirally wound and arranged on the outer peripheral surface is likely to be displaced.

[0009] The occurrence of the displacement of the Ni wire disturbs the winding / arrangement at a predetermined pitch.
A predetermined electric field is formed or the electric field distribution is fluctuated (disrupted) by the external electrodes 5. This variation in the formation of the predetermined electric field results in uneven light distribution in the tube axis direction, and
This results in a shortage of light output.

For example, in the operation of transporting or handling the fluorescent lamp having the above-described structure, after an external force is slightly consciously applied,
When a required high-frequency voltage was applied and the luminance in the tube axis direction was measured to determine the light distribution, FIG.
As shown by, it was confirmed that the light emission luminance fluctuated (the occurrence of light emission unevenness) over the entire length. Such uneven light distribution and insufficient light output result in an uneven background when used as a backlight light source of a liquid crystal display device, impairing a high-performance liquid crystal display and the like. It raises various problems.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a cold cathode fluorescent lamp with improved light distribution characteristics and light output.

[0012]

According to the first aspect of the present invention, there is provided a glass tube in which a phosphor film is formed on an inner wall surface and a discharge medium is sealed, and a lead terminal is led out to one end of the glass tube. On the sealed internal electrode, on the outer peripheral surface of the glass tube,
An external electrode formed of a conductive wire spirally wound at a required pitch over substantially the entire length in the tube axis direction, wherein at least a part of the conductive wire forming the external electrode has an outer peripheral surface of a glass tube. A fluorescent lamp characterized in that it is disposed in engagement with a locking portion formed in the fluorescent lamp.

According to a second aspect of the present invention, there is provided a glass tube in which a phosphor film is formed on an inner wall surface and in which a discharge medium is sealed, and an internal electrode which is lead-out and sealed at one end of the glass tube. And an outer electrode formed of a conductive wire spirally wound at a required pitch over substantially the entire length of the glass tube in the axial direction of the glass tube, and an outer surface of the glass tube including the external electrode integrally covered with the outer electrode. A light-transmissive resin film, wherein at least a part of the conductive wire forming the external electrode is engaged with an engaging portion formed on the outer peripheral surface of the glass tube. Fluorescent lamp.

In the first and second aspects of the present invention, the discharge medium includes, for example, neon gas, xenon gas, a rare gas mainly composed of xenon gas, or a mixed system of the rare gas and mercury.

In the inventions according to the first and second aspects, the glass tube constituting the arc tube generally has an outer diameter of about 2 to 4 mm and a thickness of about 2 to 4 mm.
The thickness is about 0.2 to 0.6 mm and the length is about 50 to 500 mm, and the phosphor layer on the inner wall surface is usually formed of a phosphor used in this type of fluorescent lamp. Further, the cylindrical body (or columnar body) forming the main body of the internal electrode is formed using a Ni-based metal such as Ni or a Ni alloy as a material.

The dimensions and structure are generally about 0.6 to 2.0 mm in outer diameter and about 2 to 5 mm in length. In the case of a cylindrical body, it is preferable to reduce the diameter of the facing end face. . Note that the connection of the lead terminal (introduction wire) to the cylindrical body or the cylindrical body is generally performed by welding or the like. Moreover, the sealing and arrangement of the internal electrodes in the glass tube are generally concentric with the glass tube.

In the first and second aspects of the present invention, the electron-emitting substance (emitter) attached to the main body (cylindrical or cylindrical) surface of the internal electrode is an emitter used in a cold cathode fluorescent lamp, for example, barium oxide. And oxides of alkaline earth metals, and borides of rare earth elements such as lanthanum boride.

In the first and second aspects of the present invention, the external electrodes spirally wound and arranged on the outer peripheral surface of the glass tube serving as the arc tube are, for example, a Ni wire or a Cu wire having a diameter of about 0.05 to 0.4 mm. . The pitch of the spiral winding depends on the outer diameter (or inner diameter) of the glass tube.
The pitch is changed depending on the position so that the light distribution is approximately uniform in the tube axis direction.

The external electrodes spirally wound and arranged on the glass tube can be locked by, for example, forming a concave portion (groove) on a part of the outer peripheral surface of the glass tube or forming a convex portion. This is performed by engaging a Ni wire or the like with these irregularities. Here, the locking of the external electrode to the glass tube is
It may extend over the entire spiral along the spiral to be wound, but it may be at least one end of the winding or a plurality of locations including the center. In any case, the formation of the locking portion is designed so that the strength and light distribution of the glass tube are not significantly impaired.

According to the second aspect of the present invention, the wrapping is performed spirally.
In order to protect the external electrode area surface arranged, as the translucent resin film to cover, for example, a tube made of heat-shrinkable polyethylene terephthalate resin, a polyimide resin film, a fluororesin film, etc. It is possible to adopt a method of protecting the coating.

According to the first and second aspects of the present invention, the external electrode spirally wound and arranged on the outer peripheral surface is locked on at least a part of the outer peripheral surface of the glass tube, and the outer electrode is slidably mounted on the outer peripheral surface of the glass tube. Movement is deterred. In other words, the external electrode spirally wound and arranged on the outer peripheral surface of the glass tube does not easily cause a positional shift even when an external force acts, so that the external electrode exhibits a predetermined light distribution, A reduction in light output is also prevented.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS. 1 (a) and 1 (b), FIG. 2 and FIGS. 3 (a) and 3 (b).

FIGS. 1 (a) and 1 (b) are cross-sectional views showing different main components of a fluorescent lamp. In FIGS. 1A and 1B, reference numeral 6 denotes a hermetically sealed glass tube functioning as an arc tube, and reference numeral 7 denotes a phosphor coating formed on the inner wall surface of the glass tube 6. Here, the glass tube 6 has, for example, an outer diameter of 2 to 10 mm.
mm, length about 50-400mm, rare gas as discharge medium,
For example, a rare gas mainly composed of xenon gas or a mercury-rare gas system is sealed.

Reference numeral 8 denotes a lead terminal (introduction wire) 9 at one end of the glass tube 6 and an internal electrode 10
Is an external electrode formed of a conductive wire spirally wound on the outer peripheral surface of the glass tube 6 over substantially the entire length in the tube axis direction.
Here, the helical pitch is appropriately adjusted so that light distribution is substantially uniform in the tube axis direction.

The internal electrode 8 is, for example, a Ni-based cylindrical body having one end opening having an inner diameter of about 2.0 mm and a length of about 4.0 mm, and having an electron emission material film provided on the inner and outer wall surfaces thereof. . The lead terminal 9 is made of, for example, W of about 1.0 mm in diameter.
One end is connected to the bottom wall of the cylindrical body by welding, while the other end is hermetically sealed and led out to the glass tube 6. Further, the external electrode 10 has, for example, a diameter
About 0.1 mm of Ni wire extends over almost the entire length of the
It is wound spirally at a required pitch of about 1.0 mm.

The external electrode 10 spirally wound on the outer peripheral surface of the glass tube 6 is at least partially engaged with the outer peripheral surface of the glass tube 6 so as not to slide. That is, a groove is formed in a part of the outer peripheral surface of the glass tube 6 in the start region of the spiral winding as shown in FIG. 1A or the start region and the end region of the spiral winding as shown in FIG. (Locking portion) 6a, and a configuration is adopted in which a part of the external electrode 10 is engaged with the groove 6a.

Further, 11 is the external electrode wound and arranged.
10 is a light-transmitting resin film that covers the outer peripheral surface of the glass tube 6 including 10. Here, the translucent resin film 11 is, for example, a fluororesin film having a thickness of about 0.1 to 1.0 μm,
The heat-shrinkable resin tube is fitted and integrated by heat shrinkage.

In the fluorescent lamp, required high-frequency voltages are applied to the internal electrodes 8 via the lead terminals 9 and to the external electrodes 10 via the lead terminals (not shown) (for example, 20 to 100 KHz, 1 to 1). When a voltage of about 2 KV is supplied), discharge by the electrodes 8 and 10 starts, and ultraviolet rays are radiated in the glass tube 6. The emitted ultraviolet light is converted into visible light by the phosphor coating 7 on the inner wall surface of the glass tube 6 and functions as a fluorescent lamp light source.

The fluorescent lamp having the above-described structure is provided with an external electrode.
At least a part of 10 is fitted to the outer peripheral surface of the glass tube 6,
Since the sliding movement is suppressed / prevented, the occurrence of light distribution unevenness in the tube axis direction is greatly improved. For example, in the transport or handling operation of each fluorescent lamp having the above configuration,
After applying the external force slightly intentionally, the required high-frequency voltage was applied, and the luminance in the tube axis direction was measured to determine the light distribution, and as shown by curve A in FIG. It was confirmed that a uniform emission luminance was exhibited.

FIGS. 3 (a) and 3 (b) are cross-sectional views showing different main components of the fluorescent lamp. In FIGS. 3A and 3B, reference numeral 6 denotes a hermetically sealed glass tube functioning as an arc tube, and reference numeral 7 denotes a phosphor coating formed on the inner wall surface of the glass tube 6. Here, the glass tube 6 has, for example, an outer diameter of 2 to 10 mm.
mm, length about 50-400mm, rare gas as discharge medium,
For example, a rare gas mainly composed of xenon gas or a mercury-rare gas system is sealed.

Reference numeral 8 denotes an internal electrode, which is connected to one end of the glass tube 6 by leading a lead terminal (introduction wire) 9;
Is an external electrode formed of a conductive wire spirally wound on the outer peripheral surface of the glass tube 6 at a required pitch over substantially the entire length in the tube axis direction.

Here, the internal electrode 8 is, for example, a Ni-based cylindrical body having one end opening having an inner diameter of about 2.0 mm and a length of about 4 mm, and having an electron emission material film provided on the inner and outer wall surfaces. The lead terminal 9 is, for example, a W-type wire or rod having a diameter of about 1 mm, and one end is connected to the bottom wall surface of the cylindrical body by welding, and the other end is hermetically sealed and led out to the glass tube 6. ing. Further, the external electrode 10 has, for example, a diameter of 0.1
0.1 to 10 mm
It is configured to be spirally wound at a pitch of the order.

The external electrode 10 spirally wound on the outer peripheral surface of the glass tube 6 is at least partially engaged with the outer peripheral surface of the glass tube 6 so as not to slide. That is, the outer peripheral surface of the glass tube 6 in the start region and the center region of the spiral winding as shown in FIG. 3A, or in the start region, the center region and the end region of the spiral winding as shown in FIG. Is formed in a groove (locking portion) 6a, and a part of the external electrode 10 is engaged with the groove 6a.

In the fluorescent lamp, required high-frequency voltages are applied to the internal electrodes 8 via the lead terminals 9 and to the external electrodes 10 via the lead terminals (not shown) (for example, 20 to 100 KHz, 1 to 1). When a voltage of about 4 KV is supplied), discharge by both electrodes 8 and 10 starts, and ultraviolet rays are radiated in the glass tube 6. The emitted ultraviolet light is converted into visible light by the phosphor coating 7 on the inner wall surface of the glass tube 6 and functions as a fluorescent lamp light source.

In the fluorescent lamp having the above-described structure, at least a part of the external electrode 10 is fitted to the outer peripheral surface of the glass tube 6 and its sliding movement is suppressed or prevented. Is also greatly improved. For example, in the operation of transporting or handling each of the fluorescent lamps having the above-described configuration, after applying an external force slightly consciously, applying a required high-frequency voltage, measuring the luminance in the tube axis direction, and obtaining a light distribution. According to the curve A in FIG. 2, it was confirmed that the light emission luminance was substantially uniform over the entire length.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the material, the outer diameter, the length, and the shape of the glass tube, the material and the locking means of the external electrode, or the material of the translucent resin film can be appropriately changed according to the use or use state of the fluorescent lamp.

[0037]

As can be seen from the above description, according to the present invention, the external electrode wire spirally wound and arranged on the outer peripheral surface of the glass tube constituting the light emitting portion of the fluorescent lamp has at least a partial area. With this, the outer peripheral surface of the glass tube is engaged, and its sliding movement is suppressed or prevented. Therefore, there is no unevenness in light emission of the fluorescent lamp or a decrease in light emission output due to the positional deviation of the spirally wound and arranged external electrode wires. That is, since a substantially uniform light emission distribution is obtained over the entire length in the tube axis direction, a suitable fluorescent lamp such as a backlight of a liquid crystal display device is provided.

In particular, in the case where the outer peripheral surface including the external electrodes is covered with a light-transmitting resin film, the sliding and movement (positional displacement) of the external electrodes are suppressed or prevented, and at the same time, the overall mechanical strength is reduced. As a result, a more reliable fluorescent lamp is provided.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are cross-sectional views showing different main components of a polar fluorescent lamp according to a first embodiment.

FIG. 2 is a characteristic diagram showing a comparison between light distributions of the fluorescent lamp according to the embodiment and a conventional fluorescent lamp.

FIGS. 3 (a) and 3 (b) are cross-sectional views showing different main components of a polar fluorescent lamp according to a second embodiment.

FIG. 4 is a cross-sectional view showing a configuration example of a main part of a conventional fluorescent lamp.

[Explanation of symbols]

 1, 6 glass tube 2, 7 phosphor coating 3, 8 internal electrode 4, 9 lead terminal (introduction wire) 5, 10 external electrode (external electrode wire) 6a grooved (Locking part) 11 ... Translucent resin film

Claims (2)

[Claims] 1. A glass tube in which a phosphor film is formed on an inner wall surface and in which a discharge medium is sealed, an internal electrode which is lead-out and sealed at one end of the glass tube, An external electrode formed of a conductive wire spirally wound at a required pitch over substantially the entire length in the tube axis direction on an outer peripheral surface, at least a part of the conductive wire forming the external electrode. Is engaged with a locking portion formed on the outer peripheral surface of the glass tube. 2. A glass tube in which a phosphor film is formed on an inner wall surface and in which a discharge medium is sealed, an internal electrode which is lead-out and sealed at one end of the glass tube, An outer electrode formed of a conductive wire spirally wound at a required pitch over a substantially entire length in the tube axis direction on the outer peripheral surface; and a translucent resin integrally covering an outer peripheral surface of the glass tube including the external electrode. A fluorescent lamp having a film, wherein at least a part of the conductive wire forming the external electrode is engaged with an engaging portion formed on an outer peripheral surface of the glass tube.