JP3147204U - Electrode structure of cold cathode fluorescent tube - Google Patents

Abstract

Provided is an electrode structure which prevents blackening around an electrode in a relatively large diameter cold cathode fluorescent tube and prevents wear of the electrode, thereby preventing a decrease in light amount and improving durability. .
As an electrode structure 1 of a cold cathode fluorescent tube having a tube diameter of about 15.5 to 38 mm, an annular ceramic cover 6 is attached to a tip opening of a cylindrical discharge electrode 5 made of an iron-based material, A glass tube 7 having translucency is placed on the outside and integrated. At this time, first and second locking projections k ₁ and k ₂ projecting inwardly before and after the glass tube 7 are provided to prevent dropping. Further, the annular ceramic cover 6 and the glass tube 7 may be integrated to form a glass tube with a cover so as to have translucency.
[Selection] Figure 2

Description

  The present invention relates to an electrode structure of a cold cathode fluorescent tube having a relatively large tube diameter that is used, for example, as an advertising backlight.

Conventionally, for example, mercury is contained in a bottomed first metal cylinder as a technique for preventing the occurrence of blackening due to discharge of a small-diameter cold cathode fluorescent tube that is frequently used as a light source for a liquid crystal backlight, for example. The sintered metal body is interpolated and joined to the lead-in wire, and the second metal cylinder is attached so as to cover the first metal cylinder, whereby the outer surface portion on the bottomed side of the first metal cylinder and the second metal cylinder are attached. The discharge electrode is a secondary electron emission coefficient so as to surround an electrode structure (see, for example, Patent Document 1) that forms a space with a metal cylinder or a discharge electrode that is joined to an introduction line. An electrode structure (for example, refer to Patent Document 2) in which a low-scattering object shielding ring is attached to an introduction line is known.
JP 2001-196024 A JP 2001-351572 A

On the other hand, the present applicant, as a neon lamp used in combination with an inverter transformer, an electrode structure (for example, a technique for preventing discharge from the electrode tip by attaching an annular ceramic to the tip of the iron electrode. (See Patent Document 3).
Utility Model Registration No. 3008035

  By the way, unlike a small-diameter cold cathode fluorescent tube such as a light source for a liquid crystal backlight, for example, in the case of a large-diameter cold cathode fluorescent tube suitable for an advertising backlight having a tube diameter of 15.5 to 38 mm, for example, 100 The amount of the electrode material that is released from the discharge electrode (sputtering) with a high frequency of about kilohertz and a current of around 30 mA is large, so that the electrode is heavily consumed, and the discharged electrode material is deposited on the inner wall of the glass bulb around the electrode. The problem that the amount of light is reduced due to the phenomenon of blackening due to the adhesion or the life is shortened has been greatly highlighted.

  Therefore, the present invention prevents blackening around the electrode in a relatively large diameter cold cathode fluorescent tube having a tube diameter of 15.5 to 38 mm and prevents wear of the electrode, thereby preventing a decrease in the amount of light. The purpose is to improve durability.

  In order to achieve the above object, according to the present invention, in the electrode structure of a cold cathode fluorescent tube having a tube diameter of 15.5 to 38 mm, an annular ceramic cover is provided at the tip opening of a cylindrical discharge electrode made of an iron-based material. The outer peripheral surface of the discharge electrode was covered with a glass tube.

  By attaching an annular ceramic cover to the tip opening of the cylindrical discharge electrode in this manner, the discharge from the electrode tip is prevented and durability is improved. At the same time, the black glass bulb around the electrode is blackened. By covering the outer peripheral surface of the discharge electrode with a glass tube, the electrode material that radiates and scatters from the discharge electrode is blocked from adhering to the glass bulb around the electrode. Prevents blackening. Moreover, the effect which interrupts | blocks the heat radiated | emitted from an electrode from being transmitted to a glass bulb | bulb is also exhibited.

At this time, the glass tube is preferably provided with translucency.
That is, in the process of manufacturing a cold cathode fluorescent tube, when the air inside the glass bulb is exhausted and filled with a rare gas, a high voltage is applied to the electrode with a powerful transformer called a bomberter to burn the discharge electrode in red. Although a process for removing impurities is employed, by providing the glass tube with translucency, it is possible to visually confirm the red state of the discharge electrode, and the operation is easy.
Further, by covering the outer peripheral surface of the discharge electrode with a light-transmitting glass tube, not only the region between the opposing discharge electrodes but also the entire glass bulb including the region on the opposite side can be brightened.

In the present invention, the ceramic cover and the glass tube are integrated.
By integrating the ceramic cover and the glass tube in this way, assembly work and the like can be easily performed, and the configuration is simplified.

  As an electrode of a cold cathode fluorescent tube with a relatively large tube diameter, an annular ceramic cover is attached to the tip opening of the iron-based cylindrical discharge electrode, and the outer peripheral surface of the discharge electrode is covered with a glass tube As a result, the blackening of the glass bulb around the discharge electrode can be suppressed, and at the same time, the consumption of the discharge electrode can be suppressed, and the heat radiated from the electrode can be blocked from being transmitted to the glass bulb, thus extending the life. I can plan. In addition, by making the glass tube translucent, the entire inside of the glass bulb can be brightened, and in the process of manufacturing a cold cathode fluorescent tube, a high voltage is applied to the electrode with a powerful transformer called a bomberter. Since the state of the discharge electrode can be visually confirmed when applying the process, the operation is easy. Further, if the ceramic cover and the glass tube are integrated, the assembling work can be facilitated.

Embodiments of the present invention will be described with reference to the accompanying drawings.
1 is an overall view showing an example of a cold cathode fluorescent tube in which the electrode structure according to the present invention is adopted, FIG. 2 is an explanatory view of a first embodiment of the electrode structure according to the present invention, and FIG. Fig. 4 is an exploded perspective view showing the electrode structure of Fig. 4, and Fig. 4 is an explanatory view when the ceramic cover and the glass tube are integrated in the second embodiment of the electrode structure.

  The electrode structure of the cold cathode fluorescent tube according to the present invention is, for example, a cold cathode type suitable for an advertising backlight having a tube diameter of 15.5 to 38 mm using a high frequency power source of about 50 to 100 kilohertz and 1 kilovolt. In addition to preventing blackening of the periphery of the electrode in the fluorescent tube and preventing wear of the electrode, it is possible to prevent a decrease in light amount and improve durability.

  As shown in FIG. 1, such a cold cathode fluorescent tube is generally provided with electrodes at both ends inside a glass bulb 2 on which an inner wall is coated with a phosphor, and a rare gas is provided inside the glass bulb 2. And a small amount of mercury are encapsulated, a high frequency is applied between the electrodes at both ends, glow discharge is performed in low-pressure mercury vapor, and phosphors are excited by ultraviolet rays generated from mercury to emit light specific to the phosphor atoms. Have been able to.

  Accordingly, the first embodiment of the electrode structure 1 at both ends of the cold cathode fluorescent tube will be described. This electrode structure 1 extends from the base pin 3 disposed at both ends of the cold cathode fluorescent tube into the glass bulb 2. And a stem 9 through which the lead wire 4 is inserted, and a cylindrical discharge electrode 5 made of an iron-based material joined to the tip of the lead wire 4 through which the stem 9 is inserted. An annular ceramic cover 6 as shown in FIG.

  The annular ceramic cover 6 is made of a material having a heat-resistant temperature of, for example, about 1000 ° C. or more that can sufficiently withstand the heat generation temperature of the electrode. As shown in FIG. 3, the small-diameter portion 6b having a small diameter and a large diameter are used. While providing the large diameter part 6a, the small diameter part 6b is made into the diameter which can be inserted in the opening diameter of the opening part of the discharge electrode 5. FIG. The large-diameter portion 6a has a diameter that can conceal the opening end portion of the discharge electrode 5, and can prevent discharge from the tip of the discharge electrode 5.

In addition, the outer peripheral surfaces of the discharge electrode 5 and the annular ceramic cover 6 are covered with a glass tube 7 having translucency and excellent heat resistance. The front and rear ends of the glass tube 7 are formed with _first and _second locking projections k ₁ and k ₂ projecting inward. The first locking projection k ₁ is annular. together to engage the front side outer peripheral portion of the ceramic cover 6, the second locking projections k ₂ engages the proximal end side outer surface of the discharge electrode 5, so as not to come out in any direction before and after Has been.

The first and second locking projections k ₁ and k ₂ are formed by, for example, inserting the small-diameter portion 6b of the annular ceramic cover 6 into the tip opening of the discharge electrode 5 as shown in FIG. after, inserted only to the first locking projections k ₁ glass tube 7 formed to advance distally from the front, then the second engagement lend熔the rear end portion of the glass tube 7 by the burner or the like forming a stopper projections k _2.

  Next, a second embodiment of the electrode structure 1 will be described with reference to FIG. 4. In this embodiment, the ceramic cover 6 and the glass tube 7 of the first embodiment are formed integrally to form a glass tube 8 with a cover. Yes. The glass tube with cover 8 prevents discharge from the tip of the discharge electrode 5 and at the same time blocks the electrode material scattered from the periphery of the discharge electrode 5 from adhering to the surrounding glass bulb 2.

  Also in this case, the glass tube 8 with a cover is provided with translucency and is formed from a material having excellent heat resistance.

The operation of the electrode structure 1 as described above will be described.
A high frequency signal of about 50 to 100 kilohertz is caused to flow between both discharge electrodes 5 through the cap pin 3 at a voltage of about 1 kilovolt to cause glow discharge in low-pressure mercury vapor, and ultraviolet light is generated in the mercury excited by the discharge. . Then, the phosphor is excited by the ultraviolet rays, and light specific to the phosphor atom is generated. At this time, in the electrode structure 1 of the first embodiment, the tip of the electrode 5 is formed by the annular ceramic cover 6 attached to the tip opening of the discharge electrode 5, and in the electrode structure 1 of the second embodiment by the glass tube 8 with a cover. As a result, the durability of the discharge electrode 5 is improved, and at the same time, the blackening around the bulb is suppressed. In addition, since the discharge electrode 5 is an iron-based material, durability does not become a problem even when a high frequency of about 50 to 100 kilohertz is applied.

  Moreover, since the outer peripheral surface of the discharge electrode 5 is covered with the glass tube 7 or the glass tube 8 with a cover, the electrode material that radiates and scatters from the discharge electrode 5 is blocked from adhering to the glass bulb 2 around the electrode. Prevents blackening. Further, the glass tube 7 or the glass tube 8 with a cover has an effect of blocking the heat radiated from the discharge electrode 5 from being transmitted to the glass bulb 2, and can extend the life of the glass bulb 2. Depending on the light transmission performance of the glass tube 7 or the glass tube 8 with a cover, not only the region between the opposing discharge electrodes 5 but also the entire inside of the glass bulb 2 including the rear region on the opposite side can be brightened.

  Further, in the process of manufacturing the cold cathode fluorescent tube, when exhausting the air inside the glass bulb 2, a high voltage is applied to the discharge electrode 5 using a powerful transformer called a bomberter to burn the electrode 5 in red. The operation of removing the impurities is carried out by covering the outer peripheral surface of the discharge electrode 5 with a light-transmitting glass tube 7 or a glass tube 8 with a cover, so that the state in which the electrode 5 is red is visually observed. It can be confirmed and the work is easy.

Further, in the case of the electrode structure 1 of the first embodiment, there is no problem that the glass tube 7 falls out of the discharge electrode 5 by the first and second locking projections k ₁ and k ₂ before and after the glass tube 7. Longer life is achieved.

  In a cold cathode fluorescent tube having a relatively large tube diameter, blackening in the vicinity of the electrode is prevented and the life can be extended. For example, it is widely used in applications such as cold cathode fluorescent tubes for advertising backlights. There is expected.

Overall view showing an example of a cold cathode fluorescent tube in which the electrode structure according to the present invention is adopted Explanatory drawing of 1st Example of the electrode structure which concerns on this invention The perspective view which decomposes | disassembles and shows the electrode structure of FIG. Explanatory drawing of 2nd Example of the electrode structure which concerns on this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrode structure, 2 ... Glass bulb, 5 ... Discharge electrode, 6 ... Cover made from cyclic ceramics, 7 ... Glass tube, 8 ... Glass tube with cover.

Claims (3)

An electrode structure of a cold cathode fluorescent tube having a tube diameter of 15.5 to 38 mm, in which an annular ceramic cover is attached to a tip opening of a cylindrical discharge electrode made of an iron-based material, and the discharge electrode An electrode structure of a cold cathode fluorescent tube, wherein the outer peripheral surface is covered with a glass tube. The electrode structure of a cold cathode fluorescent tube according to claim 1, wherein the glass tube has translucency. The electrode structure of the cold cathode fluorescent tube according to claim 1 or 2, wherein the ceramic cover and the glass tube are integrated.

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