JPH0733365Y2 - Fluorescent discharge lamp - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a mercury-filled type fluorescent discharge lamp, and in particular, is a cold cathode type that is applicable to a backlight light source of a liquid crystal display device and has a small power consumption. The present invention relates to a fluorescent discharge lamp.

[Prior art]

The applicant of the present application (Japanese Patent Application No. 56-166059)
A technique for increasing the effective light emission length by using a hollow cathode electrode has been disclosed. That is, a concave portion that protrudes outward from both axial end portions of the bulb and faces inward of the bulb is formed of metal, and the concave portion serves as a hollow cathode electrode. At this time, a mercury amalgam containing titanium and mercury, and a getter substance containing zirconium and aluminum were bonded to the bottom of the recess by a binder such as a nitrocellulose-based material and fixed under pressure. In a fluorescent discharge lamp having such a mercury-releasing structure inside, for example, by heating the mercury-releasing structure at a high frequency to about 800 ° C. after hermetically sealing the bulb, the structure is decomposed by this heat and mercury is discharged. Is released into the valve, and impure gases such as water vapor and oxygen released at this time are absorbed by the getter material. In this way, mercury is restricted from escaping to the outside and the inside of the bulb is kept in a high vacuum.

[Problems to be solved by the device]

However, when the mercury-releasing alloy or getter substance is pressure-bonded and fixed through the binder, the binder decomposes by the heat for the mercury-releasing process and releases a large amount of impure gas such as nitrogen, so that the getter substance is sufficiently released. It has been found by the present inventor that there is a problem in that it cannot be captured. Further, the heat of the mercury release treatment may peel off the amalgam that is pressure-bonded and fixed through the binder, and the peeled off may cause local discharge to make the lighting state unstable.

The object of the present invention is to make effective emission length by utilizing recesses projecting outward from both ends in the axial direction of the bulb and facing inward of the bulb. It is to provide a fluorescent discharge lamp that can be easily suppressed.

[Means for Solving the Problems]

As a means for solving the above-mentioned problems, the fluorescent discharge lamp of the present invention has a cap having concave portions protruding outward and having a concave shape at both ends of the bulb having a phosphor coating on the inner surface. Airtightly sealed, and in the recess of the cap,
The mercury-releasing structure is inserted, and an electrode member having a getter substance and functioning also as a plug is fitted on the mercury-releasing structure, and the mercury-releasing structure is fixedly held in the recess by the electrode member. Is a mercury amalgam containing no getter substance and no binder for binding the getter substance, and the getter action inside the bulb is adopted by the getter substance held by the electrode member. [Operation] According to the above-mentioned means, the gettering action in the bulb is carried out by the gettering substance of the electrode member, so that the mercury-releasing structure can be composed of only mercury amalgam. In other words, it is not necessary to bond the getter substance to the mercury amalgam with a binder,
It is possible to prevent a situation in which the binder is decomposed by the heat for releasing mercury from the mercury emitting structure and a large amount of impure gas is generated in the bulb. At this time, the mercury amalgam inserted in the concave portion is pressed and fixedly held by the electrode member fitted from above, and the mercury amalgam itself does not scatter a draku inside the bulb.

As a result, in the structure in which the effective emission length is increased by utilizing the recesses projecting outward from both ends in the axial direction of the bulb to face the inner side of the bulb, it is possible to suppress the loss of substances constituting the mercury emission structure and the increase of the impurity gas. To achieve.

〔Example〕

FIG. 1 is a sectional view of a cold cathode fluorescent discharge lamp according to an embodiment of the present invention.

The fluorescent discharge lamp 1 shown in the figure is not particularly limited,
It is a comparatively small lamp with a cold cathode structure with a power consumption of 10 watts and a total length of about 500 mm or less, and a bulb inner diameter of 10 mm or less, such as a liquid crystal display backlight light source, a copying machine exposure light source and an erase light source Is used for.

The fluorescent discharge lamp 1 includes, for example, quartz glass, soft glass,
Alternatively, a straight tube type bulb 2 made of hard glass is provided, a phosphor coating 3 is formed on the inner surface of the bulb 2, and both ends of the bulb 2 have a concave portion 4 protruding outward and having a concave shape. It is hermetically sealed by caps 5 and 6 held toward one. An inert gas such as xenon and argon, and mercury vapor are sealed in the valve 2 at a pressure of about several tens Torr to 100 Torr. According to the present embodiment, the recesses 4 of the caps 5 and 6 have a cylindrical shape, the inside of which is filled with the mercury-releasing structure 7, and the electrode member 8 which also functions as a plug is fitted from above. To be done. The electrode member 8 has a solid cylindrical shape.

Although not particularly limited, the mercury-releasing structure 7 is composed of mercury amalgam made of an intermetallic compound containing titanium and mercury, has a powdery or solid form, and does not contain a binder. The electrode member 8 is formed, for example, by mixing powder of zirconium, titanium, nickel or the like with tungsten powder, sintering and molding, and then impregnating and drying with a cesium solution. It has an emitter function to increase secondary electron emission and a getter function to absorb impure gas inside the bulb.

In the manufacturing process of such a fluorescent discharge lamp, both ends of the bulb 2 are hermetically sealed with the caps 5 and 6, and then the vicinity of the electrode member 8 is heated at a high frequency to about 800 ° C. It decomposes by heat and releases mercury into the bulb 2.
The mercury vapor discharged from the mercury discharge structure 7 is diffused into the bulb 2 through the fitting gap between the electrode member 8 functioning as a plug and the recess 4. At this time, the impure gas such as water vapor and oxygen released from the mercury structure 7 at the same time is absorbed by the getter action of the electrode member 8 activated by the heat. In this way, mercury is restricted from escaping to the outside, and the inside of the bulb 2 is kept in a high vacuum.

At this time, the electrode member 8 functioning as a plug acts as a barrier that prevents the mercury-releasing structure 7 filled in the recess 4 from scattering inside the bulb 2.
It functions so that the mercury emitting structure 7 does not need to include a binder. Therefore, even if heat is applied for the mercury release process, it is possible to prevent the substances forming the mercury release structure 7 from falling off and scattering inside the bulb 2 or an increase in impure gas. .

A pair of electrode members 8 of the fluorescent discharge lamp 1 configured as described above,
When a discharge is generated between 8, the ultraviolet rays emitted by the positive column excite the phosphor coating 3 to generate visible light. At this time, the electrode member 8 is supported by the recess 4 and the amount of protrusion into the bulb 2 is small. In other words,
There is no discharge dark part due to the internal lead wire that supports the discharge electrode. Therefore, the effective light emission length defined by the distance between the opposite end faces of the electrode member 8 becomes long. And the cap 5,6
When the metal is metallic, the cap 5, which constitutes the recess 4,
The projecting portion of 6 can be directly used as an electrical connection terminal or a support, and a base and the like are not required, so that the effective light emission length with respect to the entire length is further increased. Further, the electrode member 8 stands upright from the end face of the bulb 2, and the current density becomes high around it, so that a hollow effect can be expected.

In terms of this hollow effect, in order to make the electrode member itself a hollow cathode, it is preferable to employ the electrode member 9 having a cylindrical or conical opening 10 at its tip as shown in FIG. . As a result, a large discharge current can be supplied and the negative glow is generated by the electrode member 9
It is possible to reduce deterioration due to sputtering of the cathode without wrapping around the outside. In particular, if the depth of the opening 10 formed in the electrode member 9 is made larger than the projecting length of the electrode member 9, the effective light emission length becomes longer accordingly. still,
The electrode member 9 also has an emitter action and a getter action as described above, and also functions as a plug.

Here, focusing on the fact that mercury is released from the mercury releasing structure 7 by the heat when the caps 5 and 6 are sealed to the bulb 2, as shown in FIG. Only the cap 6 is filled, and the other cap 5
It is advisable to directly insert the electrode member 8 in. In this case, the other cap 5 is sealed first. Next, the cap 6 including the mercury-releasing structure 7 is sealed with a high frequency wave or the like, and the heat at that time causes the mercury-releasing structure 7 to discharge mercury. Therefore, the heat treatment step for activating the mercury-releasing structure 7 and the sealing step for the cap 6 can be performed at the same time. Needless to say, the electrode member 9 shown in FIG. 2 can be applied to the structure shown in FIG.

The present invention has been described above in detail based on the embodiments, but it goes without saying that the present invention can be variously modified without departing from the gist thereof. For example, although the electrode member 8 has a solid cylindrical shape in the above-described embodiment, it may have a conical shape, a truncated cone shape, or a plate-like tip. Further, the valve may have a cylindrical shape with an end.

Further, in each of the above-described embodiments, the description has been made assuming that it is applied to a backlight light source of a liquid crystal display, an exposure light source of a copying machine, an erase light source, etc., but the present invention is not limited thereto, and mercury is enclosed through a mercury emission structure. It can be widely applied to fluorescent discharge lamps under the above conditions.

[Effect of device]

 As described above, according to the present invention, the following effects can be obtained.

(1) In a structure in which a cap having a recess toward the inside of the valve is hermetically sealed at both ends of the valve, the recess of the cap is filled with a mercury-releasing structure and also functions as a plug from above. By adopting a structure in which the electrode member to be fitted is adopted, the electrode member functioning as a plug prevents the mercury emission structure filled in the back of the recess from scattering inside the bulb. Since it does not require the binder to be included in the mercury-releasing structure, the structure that increases the effective light emission length by using the recess facing inward of the bulb prevents the substances that make up the mercury-releasing structure from falling off and increasing the amount of impure gas. There is an effect that it can be suppressed.

(2) By forming a cylindrical or conical opening at the tip of the electrode member, there is an effect that the electrode member can function as a hollow cathode.

(3) By filling the mercury-releasing structure in only one of the caps, directly inserting the electrode member into the other cap, and forming the electrode member with a substance having a getter action and an emitter action. , If the cap containing the mercury-releasing structure is sealed with high frequency after the other cap is sealed first, the mercury is simultaneously discharged from the mercury-releasing structure due to the heat at that time. The release treatment can be performed in the same step.

(4) Since the cap is made of metal, the protrusion of the cap forming the recess can be directly used as an electrical connection terminal or a support.

[Brief description of drawings]

FIG. 1 is a sectional view of a fluorescent discharge lamp according to an embodiment of the present invention, FIG. 2 is a sectional view of a fluorescent discharge lamp according to another embodiment to which a hollow cathode is applied, and FIG. FIG. 9 is a cross-sectional view of a fluorescent discharge lamp according to another embodiment, which is arranged only on the cap of FIG. 1 ... Fluorescent discharge lamp, 2 ... Bulb, 3 ... Phosphor coating,
4 ... recess, 5,6 ... cap, 7 ... mercury emission structure,
8 ... Electrode member, 9 ... Electrode member, 10 ... Opening part.

Claims (3)

[Scope of utility model registration request] 1. A metal cap having air-tight recesses protruding outward and having a recessed shape toward the inner side of the bulb is hermetically sealed at both ends of the bulb having a phosphor coating on the inner surface thereof. The mercury-releasing structure is inserted into the above, and an electrode member that holds a getter substance and also functions as a plug is fitted on the mercury-releasing structure, and the mercury-releasing structure is fixedly held in the recess by the electrode member. The emission structure is a mercury amalgam containing no getter substance and a binder for binding the getter substance, and the getter action inside the bulb is performed by the getter substance held by the electrode member. . 2. A cap made of metal is hermetically sealed at both ends of a bulb having a phosphor coating on its inner surface and has concave portions projecting outward and exhibiting a concave shape toward the inside of the bulb. The mercury releasing structure is inserted into the concave part of the above, and an electrode member having a getter substance and functioning also as a plug is fitted from above, and the mercury releasing structure is fixed and held in the concave part by the electrode member. An electrode member is fitted in the recess of the other cap, and the mercury emission structure is a mercury amalgam containing no getter substance and a binder for binding the getter substance. The getter action inside the bulb is retained by the electrode member. The fluorescent discharge lamp is characterized in that the getter material is used. 3. The fluorescent discharge lamp according to claim 1, wherein the electrode member has a cylindrical or conical opening at its tip.