JP3497153B2 - Cold cathode discharge lamp and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold cathode discharge lamp used as a backlight for various liquid crystal display devices, and more particularly to a cold cathode discharge lamp which can obtain good starting characteristics even when ambient illuminance is low. Regarding the lamp.

[0002]

2. Description of the Related Art A cold cathode discharge lamp used by being incorporated in a liquid crystal device has a structure that makes it difficult for ambient light to reach the surface of the cold cathode discharge lamp, and the ambient illuminance near the cold cathode discharge lamp is 10 lux. The following dark environments are likely to occur. When the cold cathode discharge lamp is started in such a dark environment, if the initial number of electrons in the cold cathode discharge lamp, which triggers the discharge, is insufficient, it will start within 500 ms in the original bright environment. It takes several to several tens of seconds to start it. Generally, cold cathode fluorescent lamps used in liquid crystal devices are required to be immediately started in a dark environment of 0.1 lux or less, and hereinafter, the start of a cold cathode discharge lamp in such a dark environment will be discussed. Proceed.

In order to improve the dark starting characteristic, Japanese Patent Laid-Open Publication No. Hei 4 (1999) -1998
Japanese Patent Laid-Open No. 121944/1992 discloses aluminum oxide, magnesium oxide, which emits electrons to the inner surface of the bulb in the vicinity of the cold cathode with stimulating energy equal to or lower than the work function in the dark.
There is disclosed a cold cathode discharge lamp coated with an electron emitting material made of any metal oxide such as zinc oxide and lead oxide.

Further, Japanese Unexamined Patent Publication No. 2001-15065 discloses a cold cathode discharge lamp in which a cesium compound is adhered to an electrode to improve starting characteristics.

[0005]

However, in the cold cathode discharge lamp configured as described above, there are some improvements in the dark starting characteristics, but there is still a slow starting. Also, the cold cathode discharge lamp coated with the electron emitting substance has an average faster starting characteristic in the dark state than the one not coated with the electron emitting substance on the inner surface thereof, but the starting characteristic is slow in some cases. Things were included.

An object of the present invention is to solve the above-mentioned problems and to provide a cold cathode discharge lamp that can be started more quickly even in a dark environment where the ambient illuminance is 0.1 lux or less.

[0007]

The cold cathode discharge lamp according to the present invention is a cold cathode discharge lamp in which electrodes are provided at both ends of a glass tube having a phosphor layer formed on the inner surface and an enclosed substance is sealed. The first coating made of metal for starting assistance is provided on
A second coating made of a metal for starting assistance is provided on the inner surface of the glass tube in the vicinity of the first coating.

Further, the cold cathode discharge lamp of the present invention is characterized in that the electrode is not provided with a coating made of a metal for starting assistance, but the coating is made only on the inner surface of the glass tube. .

The cold cathode discharge lamp according to claim 1 of the present invention is a cold cathode discharge lamp in which electrodes are provided at both ends of a glass tube having a phosphor layer formed on the inner surface and an enclosed substance is sealed, at least one of Inner surface of the glass tube at the outer periphery of the electrode
A first coating made of a metal for starting assistance in a position opposed to the second coating, and a second coating made of a metal for starting assistance in proximity to the first coating on the inner surface of the glass tube in the vicinity of the one electrode. Is provided.

According to a second aspect of the present invention, in the cold cathode discharge lamp according to the first aspect, the second coating is formed at a position not overlapping the phosphor layer formed on the inner surface of the glass tube. Characterize.

According to a third aspect of the present invention, there is provided the cold cathode discharge lamp according to the first or second aspect, wherein the electrode has a tubular shape and the first coating film is provided on the outer periphery.

The cold cathode discharge lamp according to claim 4 of the present invention is characterized in that, in any one of claims 1 to 3, the second coating is an alkali metal, an alkaline earth metal or a mixture thereof. And

The cold cathode discharge lamp according to claim 5 of the present invention, in any one of claims 1 to 3, characterized in that the first coating, the second coating was formed with alkali metals .

The cold cathode discharge lamp according to claim 6 of the present invention is characterized in that, in claim 5, the first coating is formed of a cesium compound and the second coating is formed of cesium.

In the method of manufacturing a cold cathode discharge lamp according to claim 7 of the present invention, a cold cathode discharge lamp in which electrodes are provided at both ends of a glass tube having a phosphor layer formed on the inner surface and an enclosed substance is sealed is manufactured. At this time, an electrode having a first coating of a metal for starting assistance on the outer peripheral surface is arranged on at least one end of the glass tube, and a sealing substance is sealed, and a current exceeding a steady lighting current is applied to the electrode. Aging, the first coating is sputtered by this aging to form a second coating at a position that does not overlap with the phosphor layer formed on the inner surface of the glass tube, and the first coating is formed from the surface of the electrode. The aging is terminated in a state in which the metal does not disappear, and the first coating is formed on the surface of the electrode, and the second coating is formed on the inner surface of the glass tube.

[0016]

The cold cathode discharge lamp according to claim 8 of the present invention is the cold cathode discharge lamp according to claim 1 , wherein the starting assisting metal forming the coating is 100 to 60 of the base metal forming the electrode.
It is characterized in that the metal has a higher sputter yield than the sputter yield due to rare gas ions in the range of 0 eV.

[0018]

[0019]

[0020]

The manufacturing method of a cold cathode discharge lamp according to claim 9 of the present invention is characterized in that Oite to claim 7, aging current is 3 times twice the rated operation current.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. Here, since the cold cathode discharge lamp having the same structure at both ends is taken as an example, only one side is shown.

(Embodiment 1) FIGS. 1 (a) and 1 (b) show (Embodiment 1) of the present invention, and FIG. 1 (b) is a sectional view taken along line XX 'in FIG. 1 (a). is there.

As shown in FIG. 1, a phosphor layer 3 is formed on the inner surface of the glass tube 2, and a tube-shaped electrode 5a having an open end on the discharge side is provided at both ends thereof. The arc tube 1 is constructed by sealing a large amount of the enclosed substance. A metal internal lead-in wire 4 is connected to an end portion of at least one electrode 5a on the non-discharge side, and an external lead-in wire 7 is connected to the internal lead-in wire 4.

The electrode 5a is formed of a first metal made of a metal for assisting starting.
The second coating 9 made of a metal for starting assistance is formed on the inner surface of the glass tube 2 at a position not overlapping the phosphor layer 3 formed on the inner surface of the glass tube 2. .

The first coating 8 is made of an alkali metal compound, an alkaline earth metal compound or a mixture thereof, and the second coating 9 is made of an alkali metal or an alkaline earth metal or a mixture thereof. .

A specific example will be described below. The glass tube 2 is made of a hard material made of borosilicate glass and has a total length of 300 mm, an outer diameter of 2.4 mm, and an inner diameter of 2.0 m.
It has become m. On the inner surface of the glass tube 2, a phosphor layer 3 is formed by depositing a three-wavelength band emitting phosphor so as to have a film thickness of about 20 μm.

The internal lead-in wire 4 is made of tungsten, which has a coefficient of expansion similar to that of the material forming the glass tube 2. As the external introduction wire 7, a nickel wire having an outer diameter of 0.6 mm was used.

Both ends of the glass tube 2 are made of molybdenum and have an outer diameter of 1.7 mm, an inner diameter of 1.3 mm and a total length of 3 mm.
The 5 mm electrode 5a is provided. First coating 8
Is 10 μg or more and less than 100 μg (preferably 40 ±
0.5 μm or more in the electrode length direction with a coating amount of 20 μg 3
It is formed over a length of less than or equal to mm (preferably 1.5 ± 0.5 mm).

The second coating 9 is formed at a predetermined position as follows. The first coating 8 is applied to the electrode 5a, and the mixed rare gas of mercury, argon and neon is about 8k.
An aging current that is about 2 to 3 times the steady lighting current, for example, 18 mA to 25 mA when the steady lighting current is 8 mA, is applied to the arc tube 1 that is sealed with Pa and is not provided with the second coating 9. The aging current is applied to the electrode 5a during aging so that the electrode 5a
The first coating film 8 applied to is sputtered and deposited on the inner surface of the glass tube 2.

Here, the aging time ends when the first coating 8 does not disappear from the surface of the electrode 5a, and
The time for forming the second coating film 9 having an appropriate film thickness on the inner surface of the glass tube 2 while leaving the first coating film 8 on the surface thereof is about 10 minutes.

During aging, a discharge is generated from the discharge side opening of the tubular electrode 5a to the outer periphery where the first coating 8 is applied, and is sputtered. Since the discharge does not reach the outer periphery where the first coating 8 is applied, the first coating 8 and the second coating 9 after the aging are stable and do not disappear during use.

As described above, the first coating film 8 is provided on the surface of the electrode 5a in advance, and a metal for starting aid is sputtered by aging to be deposited on the inner surface of the glass tube 2 so that the film thickness close to the electrode 5a is obtained. It is possible to form the second coating film 9 having a uniform thickness.

According to this structure, even in a dark environment, a slight discharge is generated between the second coating 9 and the electrode 5a or between the second coating 9 and the first coating 8 to cool it. Since the initial electrons required for starting are supplied into the cathode discharge lamp, it is possible to realize a cold cathode discharge lamp with a small decrease in initial luminance and good dark starting characteristics.

With the cold cathode discharge lamp configured as described above as the product A, the dark starting delay time with the following product A for comparison was measured. The number of samples was 100. Implemented product A
The first coating 8 is formed of a cesium compound which is one of the alkali metal compounds, and the second coating 9 is formed of cesium which is one of the alkali metals. As shown in FIG. 2, the product in which the second coating 9 was not formed was designated as comparative product A.

The test conditions were as follows: the product A and the comparative product A were left in the dark with an ambient illuminance of 0.1 lux for 48 hours, and then the output voltage under the conditions of an ambient illuminance of 0.1 lux, an ambient temperature of 0 ° C. and no wind. A dark start delay time was examined using a 1200 Vrms high frequency lighting circuit (not shown). The obtained measurement result is shown in FIG.

As can be seen from FIG. 3, 90% of the samples in Example A lighted up in 0.9 msec, while in Comparative product A the required lighting time varied from 1 msec to 250 msec. As many as 6% of lamps exceeded 500 msec. In the case of the product A, the first film 8 and the second film 9
During this period, or between the second film 9 and the first film 8, a weak discharge occurs and the initial electrons necessary for starting are supplied into the low-pressure discharge lamp, and the cold cathode discharge having a very good dark starting characteristic. The lamp was obtained.

When the structure of the electrodes 5a at both ends is a different structure, the electrode on the side where the first coating 8 is formed may be connected to the high voltage side of the lighting circuit. preferable.

As the material of the first coating film 8, compounds such as Li, K and Rb of alkali metal (group I of the periodic table) can be used instead of the cesium compound. Be, Mg, Ca, S of alkaline earth metals (Group II of the periodic table)
Compounds such as r and Ba can be used.

In the above-mentioned (Embodiment 1), the electrode 5 is used.
Although the shape of a was a tube shape, even if it was a rod shape having no opening on the discharge side, a cold cathode discharge lamp having a very good dark starting characteristic as compared with the conventional product was obtained. However, in this case, in order to stably maintain the states of the first and second coatings 8 and 9 for a long period of time, the steady lighting current is limited to be lower than that of the product A in which the electrode 5a has a tubular shape. It is necessary to.

Further, in comparison with the product implemented in JP-A-2001-15065, JP-A-2001-15065
In the case of the publication, the external light reaching the cesium compound provided on the electrode is light attenuated by passing through the light emitting layer (corresponding to the phosphor layer 3 in the above embodiment) applied inside the glass tube. In most cases, the second coating film 9 is formed at a position where it does not overlap the phosphor layer 3 formed on the inner surface of the glass tube 2 as in the above-described embodiment of the present invention, and external light is attenuated. The present invention is different from the prior art in that good dark starting characteristics cannot be expected as compared with those in which a minute discharge is generated by being incident on the second coating 9 without performing the above.

(Embodiment 2) FIGS. 4 and 5 show (Embodiment 2) of the present invention, and FIG. 4 (b) is a sectional view taken along line XX 'in FIG. 4 (a).

As shown in FIGS. 4 (a) and 4 (b), a phosphor layer 3 is formed on the inner surface of the glass tube 2, and electrodes 5b are provided on both ends of the phosphor layer 3, so that an appropriate amount of the encapsulating substance is formed. Are sealed to form the arc tube 1. A metal internal lead-in wire 4 is connected to the end portion of the electrode 5b on the non-discharge side, and an external lead-in wire 7 is connected to the internal lead-in wire 4.

On the inner surface of the arc tube 1, a coating 9a made of a metal for starting assistance is formed so as to be close to the electrode 5b. In the cold cathode discharge lamp configured as described above, since a weak discharge is generated between the electrode 5b and the coating 9a made of the starting auxiliary metal to supply the initial electrons necessary for starting,
A cold cathode discharge lamp having extremely good dark starting characteristics can be obtained.

A specific example will be described below. The glass tube 2 is made of a hard material made of borosilicate glass and has a total length of 300 mm, an outer diameter of 2.4 mm and an inner diameter of 1.8 m.
It has become m. A phosphor layer 3 is formed on the inner surface of the glass tube 2 by depositing a three-wavelength band emitting phosphor so as to have a film thickness of about 20 μm.

At both ends of the glass tube 2, rod-shaped electrodes 5b made of niobium having a total length of 5 mm and an outer diameter of 1.0 mm are provided, and one end of the electrode 5b on the non-discharge side has an outer diameter of 0.
It is welded to the internal lead-in wire 4 of 8 mm. The internal lead-in wire 4 is made of tungsten whose expansion coefficient is close to that of the material forming the glass tube 2, and both ends of the arc tube 1 are sealed by the internal lead-in wire 4 and the glass tube 2. A rare gas mixture (not shown) of mercury, argon, and neon is sealed in the arc tube 1 at about 8 kPa. The other end of the internal lead-in wire 4 having one end connected to the electrode 5b is connected to an external lead-in wire 7 made of nickel and having an outer diameter of 0.6 mm.

On the inner surface of the arc tube 1 in the vicinity of the electrode 5b, a coating 9a made of auxiliary metal for starting and having a film thickness of 2 μm is formed. The auxiliary metal for starting is made of a metal having a spatter yield higher than that of the base metal of the electrode 5b in the range of 100 to 600 eV due to rare gas ions. Here, the sputter yield of the metal is higher than that of niobium which is the base metal of the electrode 5b. Large nickel is used.

The coating 9a is formed by the following procedure. On the surface of niobium forming the electrode 5b, 100 to
Nickel, which has a sputtering yield (atoms / ion) of low-energy rare gas ions in the range of 600 eV and is higher than niobium, is deposited by a method such as electrolytic plating, electroplating, and sputter deposition. The film thickness of nickel is about 5 μm so that the film thickness of the coating 8a formed on the inner surface of the arc tube 1 will be about 2 μm as described later.

The internal lead-in wire 4 is connected to one end of the electrode 5b having nickel deposited on the surface of niobium by laser welding or the like, and a cold cathode discharge lamp is assembled by a usual manufacturing method.

FIG. 5 shows a state immediately after assembly which is a pre-stage of the cold cathode discharge lamp shown in FIG. In this state, the coating film 9a is not formed on the inner surface of the arc tube 1, and nickel as the auxiliary metal for starting is deposited on the surface of the electrode 5b to form the coating film 8a.

Next, when a high current of 6 mA or more, which is a normal lighting current, for example, a current of 15 mA is applied to the electrode 5b and aging is performed for about 2 hours, nickel deposited on the surface of niobium during the aging. Sputtering is applied to the inner surface of the arc tube 1 near the electrode 5b,
A coating film 9a having a film thickness of about 2 μm is formed.

As described above, the coating 8a made of the metal for starting aid is provided in advance on the surface of the electrode 5b, and the metal for starting aid is sputtered by aging and deposited on the inner surface of the arc tube 1 so as to be close to the electrode 5b. A coating 9a of a metal for starting assistance having a uniform thickness can be formed on the inner surface of the arc tube 1 in a short time, and a cold cathode discharge lamp having a small decrease in initial luminance and a good dark starting characteristic can be easily realized.

Using the cold cathode discharge lamp prepared as described above as the product B, the dark startability was examined as follows. The test condition is that the product B was left in the dark with an ambient illuminance of 0.1 lux for 48 hours, then the ambient illuminance was 0.1 lux, the ambient temperature was 0 ° C, and the output voltage was 1200 V under no wind.
A dark starting delay time was investigated using a high frequency rms lighting circuit (not shown). The obtained measurement result is shown in FIG.

For comparison, instead of the nickel coating 9a, lead oxide, which is a metal oxide electron-emitting substance that emits electrons with stimulating energy below the work function in the dark, is used as the inner surface of the arc tube 1. To prepare a cold cathode discharge lamp. Using this cold cathode discharge lamp as a comparative product B, the dark starting delay time was examined under the same test conditions as above. The measurement result of the obtained comparative product B is shown in FIG.

As is apparent from FIG. 9, there is almost no difference in the average dark start delay time between the product B and the comparative product B, but the maximum dark start delay time is 60 in the comparative product B.
The product B was 280 msec against 30 msec, and there was no large delay as in the comparative product B. As described above, in the product B according to (Embodiment 2), the inner surface of the arc tube 1 is covered with the coating 9 made of the metal for starting assistance that is close to the electrode 5b.
By providing a, since a weak discharge is generated between the electrode 5b and the coating 9a made of the starting auxiliary metal and the initial electrons necessary for starting are supplied into the low-pressure discharge lamp, the cold cathode having a very good dark starting characteristic. A discharge lamp was obtained.

As shown in FIG. 5, the electrode 5a having the coating 8a made of the metal for starting assistance is preferably connected to the high voltage side of the lighting circuit. That is, since the both ends of the low-pressure discharge lamp have the same structure in the above-mentioned embodiment B, the electrode 5b having the coating 8a formed thereon is connected to the high-voltage side of the lighting circuit. In the case of another structure, it is preferable that the electrode on the side on which the auxiliary metal for starting is provided is connected to the high voltage side of the lighting circuit.

In order to confirm this, a cold cathode discharge lamp in which both ends of the low pressure discharge lamp have a different structure is prepared,
It was designated as Product C. The electrode on the side of the product C on which the coating 8a made of the metal for starting assistance is not provided was connected to the high-voltage side of the lighting circuit, and the dark starting delay time was measured under the same conditions as the product B. The number of samples was 100. The obtained measurement result is shown in FIG.

As is apparent from FIG. 9, the dark starting characteristic of the product C, in which the electrode on the side where the metal 8a for starting assisting is not provided is connected to the high voltage side of the lighting circuit, is better than that of the comparative product B. However, compared with the product B, the average dark start delay time of the product C is as large as 250 msec, and the maximum dark start delay time is also 480 msec.

This is because when an output voltage of the high frequency lighting circuit is applied, the electric field between the electrode and the coating made of the starting auxiliary metal that are close to each other becomes strong, so that an initial discharge occurs between the electrode and the coating made of the starting auxiliary metal. It is considered that this is because the initial electrons necessary for starting are supplied into the low-pressure discharge lamp. Thus, by connecting the electrode on the side provided with the metal for starting assistance to the high voltage side of the lighting circuit, the dark starting property can be significantly improved.

In the above description, an example in which the surface of the electrode 5b is covered with the coating 8a made of the auxiliary metal for starting has been described, but the present invention is not limited to this, and at least the surface of the electrode 5b. The auxiliary metal for starting may be provided in the.

(Embodiment 3) FIG. 6 shows (Embodiment 3) of the present invention. In this (Embodiment 3), a tubular electrode 5a is used instead of the rod-shaped electrode 5b, and a coating 9b made of a metal for starting assistance is formed on the inner surface of the arc tube 1 near the opening of the electrode 5a. Therefore, it is different from the above embodiment.

Specifically, the electrode 5a is made of molybdenum and has an outer diameter of 1.5 mm, an inner diameter of 1.3 mm and an overall length of 3 mm. On the inner surface of the arc tube 1 near the opening of the electrode 5a, a film thickness of 2 μm made of nickel, which is a metal for starting assistance, is formed.
A coating film 8b of m is formed.

The coating film 9b is formed by previously forming a nickel film having a thickness of about 5 μm on the inner surface of the electrode 5a by sputtering deposition, and a high current of 6 mA or more which is a normal lighting current, for example, a current of 15 mA which is about 2 to 3 times. By aging the electrode 5a for about 2 hours, nickel deposited on the inner surface of the electrode 5a is sputtered during the aging and adheres to the inner surface of the arc tube 1 near the opening of the electrode 5a. Formed.

The cold cathode discharge lamp configured as described above is used as a product D, and the electrode 5a having a nickel film formed on the inner surface thereof is connected to the high voltage side of the lighting circuit, and the same as the above (second embodiment). The dark start delay time was measured under the conditions. The number of samples was 100. The obtained measurement result is shown in FIG.

As shown in FIG. 9, the product D has an average dark start delay time of 70 msec and a maximum dark start delay time of 15 msec.
0 ms, which is the product B in the above (Embodiment 2)
It is even better than the dark starting characteristics of.

In this way, the tubular electrode 5 is used as the electrode.
a, and a starting auxiliary metal provided on the inner surface of the electrode 5a is adhered to the inner surface of the arc tube 1 by aging, whereby the electrode 5a
And the coating 9b made of a metal for starting auxiliary become shorter than that of the cold cathode discharge lamp in the above-mentioned (Embodiment 2), the electric field between the electrode 5a and the coating 9b becomes stronger, and the initial stage required for starting is increased. Because electrons are more easily supplied,
A significant improvement in dark starting characteristics can be realized.

In the above description, the coating film made of the auxiliary metal for starting is formed on the inner surface of the electrode 5a and is sputtered on the inner surface of the arc tube 1 by aging to form the coating film 9b. However, the present invention is not limited to this. Figure 7
As shown in FIG. 3, a coating 8b made of auxiliary metal for starting is formed on the outer surface of the electrode 5a, and the coating 8b is similarly sputtered by aging to coat the inner surface of the arc tube 1 with the coating 9c.
May be formed. In FIG. 7, by aging for about 30 minutes with a current of 20 mA, which is larger than the above description, the number of electrons required for discharge cannot be secured only by the inner surface of the electrode, and the discharge is performed from the inside of the electrode 5a through the opening portion. Since a part of the coating 8a wraps around the outer surface of the electrode 5a and the sputtering near the opening of the electrode 5a where the wraparound is strong becomes strong, both the coating 8b and the coating 9c become thinner toward the open end of the electrode 5a. However, by further increasing the aging current, the discharge can be spread over the entire outer peripheral surface of the cylindrical electrode 5b, and the coating 8b can be sufficiently sputtered to form, for example, the coating 9a shown in FIG.

(Embodiment 4) FIG. 8 shows (Embodiment 4) of the present invention. This embodiment is different from the above (Embodiment 3) in that the coating film 9d is formed on the inner surface of the arc tube 1 in the vicinity of the electrode 5a and where the phosphor layer 3 is not formed.

That is, in the cold cathode discharge lamp according to this embodiment, unlike the cold cathode discharge lamp shown in FIGS. 6 and 7, the phosphor layer 3 is extended to a position facing the outer surface of the electrode 5a. However, the glass tube 2 is exposed on the inner surface of the arc tube 1 near the opening end of the electrode 5a, and the coating 9d made of the auxiliary metal for starting is formed near the opening end of the electrode 5a.

As described above, the starting auxiliary metal is sputtered directly on the inner surface of the glass tube 2 having a good surface smoothness, not on the phosphor layer 3 to form the coating film 9d.
It is possible to obtain a coating 9d with higher accuracy than the coating formed on the phosphor layer 3 having irregularities of several microns on the surface.

The cold cathode discharge lamp configured as described above is used as the product E, the electrode 5a is connected to the high voltage side of the lighting circuit, and the dark starting delay time is measured under the same conditions as in the above (Embodiment 2). did. The number of samples was 100.

The measurement results obtained are shown in FIG. As shown in FIG. 9, the average dark start delay time of the product E is 30 m.
Second, the maximum dark start delay time was 120 msec, and the dark start characteristic was better than that of the embodiment D in the above (Embodiment 3).

In each of the above embodiments, the electrodes 5a,
5b has been described by taking a single metal as an example, the present invention is not limited to this, and alloys and sintered metals can be applied. It can also be applied to a combination of binding metals.

Further, in each of the above-mentioned embodiments, the structure in which both ends of the cold cathode discharge lamp are the same has been described as an example, but the present invention is not limited to this, and at least one of the ends. May be configured as described above.

Further, the cold cathode discharge lamp of the present invention is not limited to the above-mentioned respective embodiments, and its size, design, material, shape, rating, etc. can be appropriately selected. Also,
The electrodes are not limited to the above rod-shaped electrodes and sleeve-shaped electrodes,
For example, it may be a cylindrical electrode having a bottom or no bottom, and a sleeve-shaped electrode having a structure of two or more layers,
The sleeve electrode is not particularly limited as long as it has a practical effect such as an emitter material coated on the inner surface.

[0076]

As described above, the cold cathode discharge lamp of the present invention is a cold cathode discharge lamp in which electrodes are provided at both ends of a glass tube having a phosphor layer formed on the inner surface and an enclosed substance is sealed, at least. Inner surface of the glass tube on the outer periphery of one electrode
A first coating made of a metal for starting assistance in a position opposed to the second coating, and a second coating made of a metal for starting assistance in proximity to the first coating on the inner surface of the glass tube in the vicinity of the one electrode. By providing the above, since a weak discharge is generated between the first coating and the second coating made of a metal for starting assistance, initial electrons required for starting are supplied into the cold cathode discharge lamp, so that the dark starting characteristic Is very good.

Further, the method for manufacturing a cold cathode discharge lamp according to the present invention comprises the steps of manufacturing a cold cathode discharge lamp in which electrodes are provided at both ends of a glass tube having a phosphor layer formed on the inner surface and an enclosed substance is sealed. An electrode having a first coating of a metal for starting assistance is arranged on at least one end of a glass tube, an encapsulating substance is sealed, and a current exceeding a steady lighting current is passed through the electrode for aging. The second coating is formed by sputtering the first coating at a position that does not overlap with the phosphor layer formed on the inner surface of the glass tube, and the first coating does not disappear from the surface of the electrode. After aging, the first surface on the electrode
Since the second coating is formed on the inner surface of the glass tube, the cold cathode discharge lamp of the present invention can be easily realized.

[0078]

[0079]

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of a cold cathode discharge lamp according to (Embodiment 1) of the present invention and its XX ′ sectional view.

FIG. 2 is a cross-sectional view of a cold cathode discharge lamp which is a comparative product for comparing the starting characteristics with the embodiment.

FIG. 3 is a lighting probability distribution diagram of an implementation product of the same embodiment and a comparison product.

FIG. 4 is a sectional view showing an essential part of a cold cathode discharge lamp according to (Embodiment 2) of the present invention and its XX ′ sectional view.

FIG. 5 is a cross-sectional view showing a main part of the cold cathode discharge lamp before the coating of the metal for starting assistance in the embodiment is formed on the inner surface of the arc tube.

FIG. 6 is a sectional view showing an essential part of a cold cathode discharge lamp according to (Embodiment 3) of the present invention.

FIG. 7 is a cross-sectional view of a main part showing another example of the cold cathode discharge lamp according to the same embodiment.

FIG. 8 is a sectional view showing a main part of a cold cathode discharge lamp according to (Embodiment 4) of the present invention.

FIG. 9 is a measurement result diagram of the start-up delay time of each of the implementation products of (Embodiment 2) to (Embodiment 4) and the comparison product.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 arc tube 2 glass tube 3 phosphor layer 4 internal lead-in wires 5a, 5b electrode 7 external lead-in wire 8 first coating 8a, 8b made of metal for starting assistance 8 coating made of metal for starting assistance 9 made of metal for starting assistance Second coating 9a, 9b, 9c, 9d Coating made of metal for starting assistance

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Kihara 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-8-273589 (JP, A) JP-A-5- 290811 (JP, A) JP 2001-76617 (JP, A) JP 2000-251844 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 61/54

Claims (9)

(57) [Claims] 1. A cold cathode discharge lamp in which electrodes are provided at both ends of a glass tube having a phosphor layer formed on the inner surface and an enclosed substance is sealed , wherein at least one of the electrodes has an outer periphery facing the inner surface of the glass tube.
A first coating made of a metal for starting assistance is provided at a facing position, and a second coating made of a metal for starting assistance is provided on the inner surface of the glass tube in the vicinity of the one electrode in the vicinity of the first coating. Cold cathode discharge lamp provided. 2. The second coating film is formed at a position which does not overlap with the phosphor layer formed on the inner surface of the glass tube.
The cold cathode discharge lamp described. 3. The cold cathode discharge lamp according to claim 1, wherein the electrode has a tubular shape and the first coating film is provided on the outer circumference. 4. The cold cathode discharge lamp according to claim 1, wherein the second coating is an alkali metal, an alkaline earth metal or a mixture thereof. Wherein the first coat, a cold cathode discharge lamp according to any one of claims 1 to 3, the second coating was <br/> formed with alkali metals. 6. The cold cathode discharge lamp according to claim 5, wherein the first coating is formed of a cesium compound and the second coating is formed of cesium. 7. When manufacturing a cold cathode discharge lamp in which electrodes are provided at both ends of a glass tube having a phosphor layer formed on the inner surface and a sealed substance is sealed, at least one end of the glass tube is used as a starting aid. An electrode having a metal first coating on the outer peripheral surface is arranged and the encapsulating material is sealed, and a current exceeding a steady lighting current is passed through the electrode for aging, and the aging causes sputtering of the first coating. A second coating is formed on the inner surface of the glass tube at a position that does not overlap with the phosphor layer, and the aging is terminated in a state in which the first coating does not disappear from the surface of the electrode, and the surface of the electrode. A method of manufacturing a cold cathode discharge lamp, wherein a first coating is formed on the inner surface of the glass tube, and a second coating is formed on the inner surface of the glass tube. 8. The starting aid for a metal forming the coating, a large metal cold according to claim 1, wherein the sputtering yield than the sputtering yield by noble gas ions 100~600eV range of the base metal forming the electrode Cathode discharge lamp. 9. A manufacturing method of a cold cathode discharge lamp according to claim 7 Symbol mounting aging current is 3 times twice the rated operation current.