JP2003123692A - Cold-cathode fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold-cathode fluorescent lamp which can restrain lamp voltage rise more effectively and maintain excellent starting characteristics and high brightness. SOLUTION: With the cold-cathode fluorescent lamp provided with a glass tube 1 equipped with a phosphor layer 2 on its inner wall face and with rare gas and mercury sealed in, a pair of lead-in wires 3 led in and sealed in opposition at both ends inside the glass tube 1, and an electrode 6 each electrically connected and mounted in sealing at opposing tip part of the lead-in wires, a cesium compound layer 5 is set in protrusion by 0 to 2.5 mm from the tip part on the face of the phosphor layer 2 opposing the electrode at both ends of the glass tube 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a cold cathode fluorescent lamp.
More specifically, a cold cathode fluorescent lamp with improved performance
About the pump. [0002] 2. Description of the Related Art For example, liquid crystal displays, word processors, etc.
Liquids such as processors and personal computers
Crystal display devices are becoming increasingly sophisticated as their applications expand or spread.
There is a demand for performance, miniaturization, and long life. like this
Responding to such demands as a light source for backlight
Even in cold cathode fluorescent lamps (cold cathode low-pressure discharge lamps)
There is an inevitable demand for improved performance and the like. FIGS. 4A and 4B show light for a backlight.
Overview of cold cathode fluorescent lamps conventionally used as a source
FIG. 4A shows the overall structure, and FIG.
(B) is a partially enlarged sectional view. 4 (a) and 4 (b)
And 1 is a phosphor that emits light when stimulated by ultraviolet rays on the inner wall
A layer 2 is provided and a rare gas such as neon or argon
Glass tube containing glass and mercury as the discharge medium
Lubes) 3, 3 are sealed facing both ends of the glass tube 1.
The pair of leading lines 4, 4 and 4 that have been introduced are the leading lines 3, 3
Are electrically connected to the opposite ends of the glass tube 1 respectively.
This is the electrode sealed in. The glass tube 1 has an inner diameter of 1.2 to 4.
The length is about 8 mm and the length is about 40 to 800 mm. Also,
In the glass tube 1, for example, 0.5 to 2.0 mg /
cm ³Of mercury and 8000 to 20000 Pa (6
A rare gas of about 0 to 150 Torr is sealed as a discharge medium.
Has been entered. Further, in the above configuration, the electrode 4 is
For example, the inner diameter is about 0.6 to 1.7 mm, and the wall thickness is 0.1 to 0.1 mm.
A cylinder having a length of about 2 mm and a length of about 2 to 3 mm (for example,
A cylindrical body 4a made of a rubber material) and an outer surface of a side wall of the cylindrical body 4a.
And an emitter layer 4b coated and baked.
You. These electrodes 4 are cylindrical members 4 which are constituent members.
The tip of a pair of lead-ins 3 that are sealed and introduced on the outer bottom surface of a
Parts are electrically connected by spot welding, etc.
It is mechanically joined and fixed. That is, the cold cathode 4,
4 is applied with a required voltage, and electrodes 4 and 4 are used as discharge electrodes.
Function. Note that the emitter layer 4
b is generally a barium compound, yttrium compound
Emission properties of substances, lanthanum compounds, cesium compounds, etc.
It is formed of a material mainly composed of a substance. And d
A pair of electrodes 4, 4 carrying the mitter layer 4b are
When energized through 3, 3, discharge starts easily and UV
A line is radiated, and this ultraviolet light is converted into visible light by the phosphor layer 2.
To function as a cold cathode fluorescent lamp. [0007] The cold cathode fluorescent light
Lamps are integrated into the backlight unit, for example
In this case, the starting takes place in the dark, where the discharge takes several seconds.
There may be a delay. As a measure against this discharge delay,
Normally, aging lighting is performed at a high current and forced
Blackened. However, the above-mentioned forced blackening of the sputters
This will promote wear and shortening of the life of the pole 4
In addition, the luminous efficiency or luminance is reduced. Like this
In order to avoid or reduce the problem of blackening,
For example, by supporting an emitter such as cesium oxide,
It is also known to perform aging lighting with a flow. Only
And the consumption of the emitter due to sputtering during lighting
There was a problem that the lamp voltage increased during lighting.
It is not a sufficient countermeasure. In other words, the starting characteristics
The problem is usually in the dark, causing a discharge delay.
Liquids (by reducing the initial electrons) is an important issue
Lamp life, such as in the backlight of
Adding a point raises a serious problem. The present invention has been made in view of the above circumstances.
Therefore, maintaining excellent starting characteristics and high light emission brightness,
Of a cold cathode fluorescent lamp suitable for the light source of a backlight unit
For the purpose of providing. [0010] According to the first aspect of the present invention, an inner wall is provided.
Phosphor layer is provided on the surface and noble gas and mercury are enclosed
Glass tube, facing both ends in the glass tube
A pair of lead-ins that are sealed and introduced, and opposing ends of the lead-in
Parts that are electrically connected to each other and sealed.
Cold-cathode fluorescent lamp, wherein both ends of the glass tube
And the electrode tip on the phosphor layer surface in the area facing the electrode
Cesium compound layer
It is a cold cathode fluorescent lamp characterized in that it is illuminated. According to the first aspect of the present invention, a discharge medium is provided in a glass tube.
As a rare gas and mercury
Cold cathode fluorescent lamp with a pair of electrodes sealed at both inner ends
Results of examining countermeasures against discharge delay in darkness
It is based on. That is, cold cathode fluorescent light
Phosphor layer on both sides of the lamp and in the area facing the electrodes
A cesium compound having an electron emission property, for example, an acid
When a cesium fluoride layer is provided, discharge delay in dark
Have been found to be improved and have led to the present invention.
You. [0012] To further mention, the present inventor has described electron emission.
Cesium oxide (cesium compound) having a conductive property on the electrode surface
Instead of carrying it, the phosphor layer surface in the area facing the electrode
To detect discharge delay measures in darkness.
We discussed and evaluated. For example, an outer diameter of 1.8 mm and a length of 200
For construction of cold cathode fluorescent lamps using mm glass tubes as arc tubes
FIG. 1 is an enlarged cross-sectional view of a main part configuration.
The electrode 4 of the phosphor layer 2 on the inner wall surface of the glass tube 1
The cesium oxide layer 5 is provided in the region facing
Was. [0013] And, about these cold cathode fluorescent lamps,
When the discharge delay time in darkness was measured,
The tendency as shown in FIG. 2 (a) was confirmed. That is, FIG.
As schematically shown in (b), the tip of the electrode 4 is
Then, the surface of the phosphor layer 2 facing the electrode 4 is
When the metal layer 5 is provided, the discharge delay in darkness (starting
Was found to be significantly improved. Where the electrodes
Oxide on the surface of the phosphor layer 2 in the region facing the surface 4
The layer 5 is made of cesium oxide based on the tip of the electrode 4.
The tip of the layer 5 projects from 0 to 2.5 mm, more preferably 0
Excellent starting characteristics when projecting
On the other hand, it consumes less light and has a longer life.
Can be The thickness (layer thickness) of the cesium compound is 5 to 5.
It may be about 10 μm, and it is not a uniform layer but spots.
It may be formed. Here, as the electron-emitting substance, in particular,
Cium compounds (for example, cesium oxide, cesium sulfate,
(E.g., cesium chromate)
Work function, lower lamp voltage,
This is because the discharge delay in darkness is significantly improved.
You. In FIG. 2A, the cesium oxide layer 5 is not provided.
The case where it was found is shown for comparison. In the first aspect of the present invention, the glass tube is
Generally, the inner diameter is about 1.2 to 4.8 mm, and the length is 40 to 80.
0 mm, and a discharge medium is provided in the glass tube 1.
For example, 0.5 to 2.5 mg / cm³Degree of mercury,
And a rare gas such as neon or argon 8000 to 200
Rare gas of about 00Pa (60 to 150 Torr) is sealed
Have been. In the first aspect of the present invention, the electrodes are
If the inner diameter is about 0.6 to 1.7 mm, the wall thickness is 0.1 to 0.2 m
m, tantalum or molybdenum about 2-4 mm long
It is composed of a metallic cylindrical body. And this electrode
Is one that is electrically connected to the outer bottom wall of the metal cylinder.
On the other hand, the end of the glass tube is sealed
The required electric power is applied from the outside. [0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An example will be described. FIG. 1 shows a cold cathode fluorescent lamp according to an embodiment.
It is an expanded sectional view showing an important section composition. In FIG. 1, 1 is
Phosphor layer 2 that emits light when stimulated by ultraviolet rays is provided on the inner wall surface
Glass tube filled with noble gas and mercury, 6
Are sealed opposite to both ends of the glass tube 1, respectively.
A pair of electrodes (discharge electrodes), 5
With reference to the surface of the phosphor layer 2 in a region facing the electrode 4,
It was provided so as to protrude 0 to 2.5 mm from the tip of the pole 4
It is a cesium oxide layer. Here, the glass tube 1 has, for example, an outer diameter of 2.
6 mm, inner diameter 2.0 mm, length 220 mm, for example
2.5mg / cm³Degree of mercury, and 10664 Pa
(80 Torr) rare gas such as neon or argon
Is enclosed. In this specific example, cesium oxide
The memory layer 5 is aligned with the tip of the electrode 4 (with a protrusion of 0 m).
m), it is provided up to the sealing edge. In addition, the electrodes
6 is a nickel metal with an outer diameter of 1.7 mm and a length of 2.8 mm
It consists of a cylindrical body made of. Further, the electrode 5 is provided with the glass tube.
Insert the leading end of the lead-in wire 3 that is sealed and led out into the end of a cylindrical body
6. Joined to the outer bottom wall by spot welding etc.
The electrical connection is made with the permanent fixation. Toes
When a pair of electrodes 6 are energized through the introduction wire 3,
Ultraviolet rays are emitted by energization, and the ultraviolet rays are
To convert it into visible light and function as the required light source
And With respect to the cold cathode fluorescent lamp having the above structure,
A continuous lighting test was performed under the condition of a pump current of 5 mA.
At this time, as shown by curve A in FIG.
However, little change was observed in the valve voltage.
In addition, it retains and demonstrates a luminous flux comparable to the initial lighting period, extending its life.
It was also confirmed that the luminous efficiency was excellent. Toes
Thus, the cold cathode fluorescent lamp according to the embodiment is
It has low work function and good emitter properties.
Therefore, increase in lamp voltage during long-time operation
Emitting electrons by the emitter is more efficient
It has excellent starting performance and long life
Life is ensured. For comparison, a conventional cold cathode fluorescent lamp (FIG.
4), adjust the relationship between the lighting time and the lamp voltage.
The solid result is also shown in FIG. That is,
In the configuration of the cold cathode fluorescent lamp, the electrode 4 is made of nickel.
Coating and baking on the cylindrical body 4a and the outer peripheral surface of the cylindrical body 4a
The electrode 4 is sealed with the emitter layer 4b.
-Cold cathode fluorescent lamps of the same standard except that they are provided (Fig. 4
About the change of the valve voltage under the same conditions as above.
As a result of the examination, the result was as shown by a curve a in FIG. As can be seen from the above embodiment, the present invention
Such a cold cathode fluorescent lamp has a phosphor in an area facing an electrode.
On the layer surface, provided a cesium compound layer having electron emission
As a result, stable starting performance even in the dark
Present. Also, the emitter carrying / forming surface increases.
While the amount of emitter increases,
There is no wear. That is, the sputtering of the emitter
Along with the prevention and reduction, the life can be extended. The present invention is limited to the above embodiment.
Various modifications without departing from the spirit of the invention.
Can be taken. For example, the diameter of the glass tube forming the arc tube
And length dimensions, electrode spacing, electrode material (for example, molybdenum
Den, tantalum-based alloys and molybdenum-based alloys)
The law can be changed and set as appropriate. [0025] According to the first aspect of the present invention, cesium is applied to the electrode.
Cold-cathode fluorescent lamps with a coating
Consumption of cesium oxide etc. is suppressed compared to
For this reason, the cold cathode fluorescent lamp has a small size with excellent startability and a long service life.
A light lamp is provided. That is, the resistance of the cesium oxide layer
The improvement in sputtering performance depends on the lamp voltage during the life.
(Cathode drop voltage) rise, low power of cold cathode fluorescent lamp
It also increases power and efficiency. Therefore, small, high effect
Suitable for LCD backlights that require high efficiency and long life
A cold cathode fluorescent lamp is provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged sectional view showing a configuration of a main part of a cold cathode fluorescent lamp according to an embodiment. FIG. 2 (a) is a characteristic diagram showing an example of the relationship between the lighting time and the discharge delay time for the cold cathode fluorescent lamp according to the example and the conventional cold cathode fluorescent lamp, and FIG. 2 (b) shows the position of the cesium compound layer with respect to the electrode. The schematic diagram which shows a relationship. FIG. 3 is a characteristic diagram showing an example of the relationship between lighting time and lamp voltage for the cold cathode fluorescent lamp according to the example and the conventional cold cathode fluorescent lamp. 4A and 4B schematically show the configuration of a conventional cold cathode fluorescent lamp, in which FIG. 4A is an overall sectional view, and FIG. 4B is an enlarged sectional view of a cold cathode sealing region. [Description of Signs] 1 ... Glass tube 2 ... Phosphor layer 3 ... Introduction line 4, 6 ... Electrode 4a ... Nickel cylinder 4b ... Emitter layer 5 ... Cesium compound layer (cesium oxide layer)

Claims (1)

Claims: 1. A glass tube provided with a phosphor layer on an inner wall surface and filled with a rare gas and mercury, and a pair of sealing tubes introduced opposite to both ends in the glass tube. And a cold-cathode fluorescent lamp having an electrode electrically connected to the leading end of the introduction line and sealed, respectively, wherein both ends of the glass tube and a region facing the electrode A cold cathode fluorescent lamp comprising a cesium compound layer provided on a surface of a phosphor layer so as to protrude from an electrode tip by 0 to 2.5 mm.