CN101377996A

CN101377996A - Discharge lamp

Info

Publication number: CN101377996A
Application number: CNA2008102100850A
Authority: CN
Inventors: 青浪由广
Original assignee: Harison Toshiba Lighting Corp
Current assignee: Toshiba Lighting and Technology Corp
Priority date: 2007-08-31
Filing date: 2008-08-20
Publication date: 2009-03-04
Also published as: TW200926247A; JP2009076445A; KR20090023112A

Abstract

The discharge lamp of this invention includes an airtight container (1) formed by closing both ends, the inner of which is sealed with discharge medium; and a pair of cup-shaped electrodes (5) which is configured at the end inside the airtight container, has a bottom (51) and a lateral part (52), and has an open end. The bottom of the electrode has a dent at a section plane along the shaft direction, satisfying a relationship D/W>=0.5, wherein, the depth of the dent (511) is D, and the width is W.

Description

Discharge lamp

Technical field

The present invention relates to the backlight used discharge lamp of liquid crystal TV set, personal computer etc.

Background technology

Current, the use backlight of liquid crystal TV set, personal computer be cold-cathode fluorescence lamp.Cold-cathode fluorescence lamp presents such formation as for example patent documentation 1～7 discloses: comprise the inner gas-tight container that has discharge medium, closed at both ends to form of enclosing; And in this gas-tight container a pair of cup-shape electrode that all has sidepiece and bottom that forms opposite each other.

But there are the following problems for this cold-cathode fluorescence lamp, lights the time (designed life) before reaching practical, and there is perforation near the side the sidepiece of electrode, especially the electrode bottom, the result be lantern festival to the life-span, can not reach the designed life of expection.

Avoid this problem, patent documentation 8 forms stage portion at the inner bottom part of cup-shape electrode, even if the consumption of electrode sidepiece increases in the feasible use, also can avoid the perforation of electrode sidepiece.

But it is concavo-convex that the method for patent documentation 8 records is formed with at the electrode inner surface, thereby exist this jog discharge to concentrate such problem.Therefore, it is invalid to have distinguished that this constitutes near the sidepiece perforation the electrode bottom.

Patent documentation 1: TOHKEMY 2005-108452 communique

Patent documentation 2: TOHKEMY 2005-302355 communique

Patent documentation 3: TOHKEMY 2005-327485 communique

Patent documentation 4: TOHKEMY 2005-71972 communique

Patent documentation 5: TOHKEMY 2002-289136 communique

Patent documentation 6: TOHKEMY 2007-87752 communique

Patent documentation 7: TOHKEMY 2004-47328 communique

Patent documentation 8: TOHKEMY 2007-141593 communique

Summary of the invention

Its purpose of the present invention is that boring a hole by inhibition electrode sidepiece provides long-life discharge lamp.

In order to achieve the above object, discharge lamp of the present invention is characterized in that, comprising: the inner gas-tight container that has discharge medium, closed at both ends to form of enclosing; And be disposed at described gas-tight container inner end, have bottom and sidepiece and a pair of cup-shape electrode of an end opening arranged, its section axially of the bottom of described electrode has recess, and its concave depth is that D, width are to satisfy this relation of D/W ≧ 0.5 under the situation of W making.

According to the present invention, can provide long-life discharge lamp by suppressing electrode perforations.

Description of drawings

Fig. 1 is the used cutaway view of discharge lamp of explanation embodiment of the present invention.

Fig. 2 is the enlarged drawing of the chain-dotted line part among Fig. 1.

Fig. 3 is the stereogram of electrode etc.

Fig. 4 is the used key diagram of perforation time of origin of the lamp of explanation conventional example and embodiment.

Fig. 5 is the point of the lamp of explanation conventional example and the embodiment used key diagram of time of origin that do not work.

Fig. 6 concerns used key diagram for the tube voltage of the lamp of explanation conventional example and embodiment with respect to tube current.

Fig. 7 concerns used key diagram between the two for D/W and lamp perforation time of origin is described.

Fig. 8 is the used key diagram of explanation discharge lamp first variation of the present invention.

Fig. 9 is the used key diagram of explanation discharge lamp second variation of the present invention.

Figure 10 is the used key diagram of explanation discharge lamp the 3rd variation of the present invention.

Figure 11 is the used key diagram of explanation discharge lamp the 4th variation of the present invention.

Embodiment

The discharge lamp of embodiment of the present invention is described with reference to the accompanying drawings.Fig. 1 is the used cutaway view of discharge lamp of explanation present embodiment, and Fig. 2 be the chain-dotted line enlarged drawing partly among Fig. 1, and Fig. 3 is the stereogram of electrode etc.

The discharge lamp of present embodiment, for example utilizing, the glass tube that soft glass constituted 1 such as pyrex forms discharge vessel.The inside of glass tube 1 is formed with discharge space 11, encloses inert gas and the mercury (Hg) have the mist of neon (Ne) and argon gas (Ar) for example to form in the discharge space 11.And the inner surface of glass tube 1 is formed with for example formed luminescent coating 2 of 3 wavelength fluorescent bodies of RGB.

The both ends of glass tube 1 are sealed with electrode tip holder 3.Electrode tip holder 3 is made of bead 4, electrode 5, inner lead 6 and outer lead 7.Bead 4 is packaged on the end of glass tube 1 with air tight manner, and glass tube 1 just constitutes gas-tight container thus.Bead 4 is better by being formed with the same material of glass tube 1.

Electrode 5 is relative with the end of discharge space 11 to be disposed.At this moment, comparatively ideal is that gap with glass tube 1 inner peripheral surface is (to be limited to this degree of noncontact down) below the 0.15mm, and manages mainly the inner surface generation glow discharge at electrode 5.

In addition, as electrode material, can use a kind of metal of being selected from the middle of nickel (Ni), molybdenum (Mo), tungsten (W), niobium (Nb), tantalum (Ta), titanium (Ti) and the rhenium (Re), sintered body or with they alloys as main body.

Inner lead 6 is formed by for example molybdenum, and wherein an end engages with electrode 5, and the other end exports to the outside by glass tube 1.Outer lead 7 is formed by for example Dumet copper-clad iron-nickel alloy filament (the nickel line that copper Cu coated), and wherein an end engages with inner lead 6.

Here further specify the structure of electrode 5 with reference to Fig. 2, Fig. 3.Electrode 5 has a bottom opening shape (cup-shaped) for what have bottom 51 and a sidepiece 52, and its bottom 51 is formed with the recess 511 that axial section is curve form in the inboard of electrode 5, then is formed with planar portions 512 in the outside.

Recess 511 is in that to make its degree of depth be D, when width is W, need satisfy D/W ≧ 0.5.Specifically, the bottom 51 that electrode 5 has comprises the recess 511 that satisfies D/W ≧ 0.5 this necessary condition, thereby the thickness of sidewall sections increases in fact to some extent in the bottom 51 of electrode 5.And recess 511 its axial sections are curve form, thereby can not concentrate discharge.

So along with the use to above-mentioned discharge lamp, the sidewall sections of bottom 51 that can be by making electrode 5 becomes heavy wall, prevents this part perforation, thereby can prolong the life-span of discharge lamp.

In addition, the section shape of recess 511 so long as function as described above effect, is not only as shown in Figure 2 with regulation curvature such curved surface continuously, also can comprise the concavo-convex shape that how much has that is difficult to take place to concentrate degree of discharge.Specifically, also can be waveform shape or polygon-shaped.

And it is such that following mask body illustrates, by satisfying this necessary condition of D/W ≧ 1.0, comes to function as described above more significantly effect.

In addition, comparatively ideal is that the wall thickness T 1 of bottom 51 central authorities and the wall thickness T 2 ratio between two T2/T1 of end satisfy 1.5 ≦ T2/T1 ≦ 3.0 this relations.Thus, can suppress the perforation of electrode 5 bottom sidewalls, and can suppress the consumption of electrode 5 bottoms 51, and prevent to be connected electrode that releasing the caused caused some situation that do not work that comes off with inner lead 6.

Specifically, the wall thickness T 3 of electrode 5 is under the situation of 0.05mm～0.2mm, can make the wall thickness T 1 of bottom 51 central authorities be 0.2mm ≦ T1 ≦ 1.0mm, and the wall thickness T 2 of end is 0.5mm ≦ T2 ≦ 2.0mm.

In addition, the wall thickness T 3 of electrode 5 be the machining area having considered will to guarantee the electrode inboard at the electrode external dimensions that is restricted more greatly and the intensity of using in fact decide.

Here, kind electrode 5 can will for example be cast, forge formed bottom 51 and be processed to form through curling to sidepiece 52 both joints of tubular and easily make by welding etc.In addition, when electrode forms, the more satisfactory continuous shape that forms no step drop etc. for the inner surface of electrode 5.

Provide the embodiment of a routine discharge lamp of the present invention below.

● glass tube 1: pyrex, internal diameter=2.0mm, external diameter=3.0mm, total length=about 200mm,

● discharge medium: neon (Ne)+argon gas (Ar), mercury (Hg),

● luminescent coating 2:3 wavelength fluorescent body,

● bead 4: pyrex,

● electrode 5: bottom 51 and sidepiece 52 are nickel (Ni), cup-shaped, direction of principal axis length=4.0mm, external diameter=1.7mm, internal diameter R=1.4mm, depth D=0.8mm, width W=0.7mm, central wall thickness T1=0.5mm, end wall thickness T2=1.3mm, sidepiece wall thickness T3=0.15mm

● inner lead 6: molybdenum (Mo), diameter=0.8mm,

● outer lead 7: Dumet copper-clad iron-nickel alloy wire, diameter=0.6mm.

It is that the life characteristic of lamp of the conventional example of 0.5mm is compared with the lamp of the foregoing description that the inboard of bottom 51 and the outside are plane, wall thickness.Fig. 4 illustrates its result.

Fig. 4 is the used key diagram of perforation time of origin of the lamp of explanation conventional example and embodiment, around under the temperature of 25 ± 5 ℃ of temperature, utilizes the one-sided high pressure of lighting current 10mA, frequency 55kHz to light a lamp and tests.

By the result as can be known, the perforation time of origin of the lamp of Comparative Examples is about 5000 hours, and with respect to this, the lamp of embodiment is about 6000 hours.That is to say that the lamp of embodiment is compared with the lamp of Comparative Examples, it is about 20% that near its perforation time of origin of the sidepiece the electrode bottom improves, and life characteristic improves.

Investigate the reason that above-mentioned routine middle punch time of origin improves below.Cup-shape electrode, because hollow cathode effect, thereby in life, carry out consumption of electrode.Though the consumption bottom center of this electrode is relatively fiercer, the boundary perimeter of bottom and sidepiece also takes place.Be perforation because of the bottom of this boundary perimeter and sidepiece eliminate the consumption of electrode that takes place, especially the sidepiece of the boundary vicinity of thin-walled takes place easily.

Electrode of the present invention has bottom 51, and the recess 511 that described bottom 51 is comprised satisfies this necessary condition of D/W ≧ 0.5, so the tangible increase of its thickness of sidewall sections in the bottom 51 of electrode 5.And recess 511 its axial sections are curve form, thereby discharge is not easy to concentrate.Therefore, can think that the perforation time of origin is significantly improved.

In addition, the external surface shape of recess 511, for the consideration of guaranteeing the convenience aspect that bottom wall thickness, inner lead connect, comparatively ideal is to be flat shape.

Thereby, if under the perforation state, then continue the some lantern test, just lamp is extremely put the state that do not work shown in the result of Fig. 5.This be because, electrode is in case perforation just produces cathode glow towards glass tube thus, this cathode glow makes glass tube consumption and causes inert gas to leak.The point of the lamp of the Comparative Examples time of origin that do not work is about 6300 hours, and the some time of not working of the lamp of embodiment is about 7400 hours, and the present invention improves about 17%.

On the other hand, the lamp of embodiment is owing to the variation of its bottom shape, and the machining area of electrode interior is littler than the lamp of conventional example, thereby worries that tube voltage can improve.The tube voltage of embodiment is the identical value of cardinal principle with conventional example, and modulation characteristic is reduced, and life characteristic is improved but as shown in Figure 6 as can be known.

Here, the perforation time of origin of electrode sidepiece be subjected to recess 511 shape especially the depth D of recess 511 and width W concern the influence that D/W is bigger.Therefore, the different electrode of D/W has been carried out the test of perforation time of origin.It the results are shown among Fig. 7.

As shown in Figure 7, on the whole, have that D/W is big more, the long more this trend of the perforation time of origin of electrode sidepiece.But the perforation time of origin make moderate progress for D/W ≧ 0.5, more effective be the situation of D/W ≧ 1.0, D/W=0.2 does not then have and so on variation with respect to existing electrode.Thereby, the depth D of recess 511 and width W concern D/W, be desirably D/W ≧ 0.5, even more ideal is D/W ≧ 1.0.But because in a single day D/W becomes greatly, the machining area of electrode inboard just can diminish, thereby D/W ≦ 5.0 are comparatively suitable.

And, the wall thickness T 1 of bottom 51 central authorities and the wall thickness T of end 2 ratio between two T2/T1, it is satisfied that 1.5 ≦ T2/T1 ≦ 3.0 these relations are more satisfactory.Thus, except the perforation that can suppress electrode 5 bottom sidewalls, can also suppress the consumption of electrode 5 bottoms 51, prevent the electrode that releasing caused that is connected with the inner lead 6 caused some situation that do not work that comes off.

In sum, in the present embodiment, electrode 5 has bottom 51 and sidepiece 52, bottom 51 comprises the recess 511 of the section with curve form, and be that D, width are to satisfy D/W ≧ 0.5 under the situation of W in the degree of depth that makes recess 511, the position of coming reinforcement electrode sidepiece to bore a hole easily thus, thereby can realize long-life discharge lamp.In addition, the shape of recess 511 is curve form, thereby can avoid concentrating discharge, thereby can suppress local consumption of electrode, further promotes above-mentioned long lifetime.

And, by design bottom 51, so that be under the situation of 0.05mm～0.2mm in the wall thickness T 3 of electrode 5, the wall thickness of order central authorities is T1, when the wall thickness of end is T2, satisfies 0.2mm ≦ T1 ≦ 1.0mm, and 0.5mm ≦ T2 ≦ 2.0mm suppresses electrode perforations thus and electrode comes off.

More than provide concrete example and the present invention is had been described in detail, but the invention is not restricted to foregoing, only otherwise deviate from category of the present invention, can carry out all distortion or change according to the working of an invention mode.

For instance, be that the sidepiece 52 around bottom 51 engagement cylinder shapes forms electrode 5 in the above-mentioned example, also can be as shown in Figure 8, by welding or be pressed into the tip side formation sidepiece 52 that waits in the bottom 51 of a part of bearing sidepiece 52.And, in order further to remedy the consumption of bottom 51 peripheries, also can be illustrated in figure 9 as the electrode that sidepiece 52 is engaged with the bottom 51 of heavy wall.And, also can be the electrode that sidepiece 52 is engaged with the bottom 51 that is formed with inner lead 6.

Bottom 51 and sidepiece 52 also can be the combination of dissimilar metal.For instance, it is proper to carry out following combination: the metal material of processing is easily adopted in the bottom 51 that forms recess, and the comparatively favourable sidepiece 52 of thin-walled adopts the metal material that is not easy to consume.

And bottom 51 and sidepiece 52 do not need separately, can wait integrally formed by sintering, deep draw processing yet.

In addition, recess 511 also can be made of straight line and curved surface as shown in figure 10.In this case, as long as satisfy D/W ≧ 0.5, just can suppress the perforation of electrode sidepiece equally with above-mentioned example.

And as shown in figure 11, the outside of bottom 51 needn't be the plane, also can have curved surface.But the part with inner lead 6 is connected is preferably the plane.

Claims

1. a discharge lamp is characterized in that, comprising:

The inner gas-tight container that has discharge medium, closed at both ends to form of enclosing; And

Be disposed at end in the described gas-tight container, have bottom and sidepiece and the cup-shape electrode of an end opening arranged,

Its section axially of the bottom of described electrode has recess, and its concave depth is that D, width are to satisfy this relation of D/W ≧ 0.5 under the situation of W making.

2. discharge lamp as claimed in claim 1 is characterized in that, satisfies this relation of D/W ≧ 1.0.

3. discharge lamp as claimed in claim 1 or 2 is characterized in that, the wall thickness T 1 of described bottom center and the wall thickness T of described bottom end 2 ratio between two T2/T1 satisfy 1.5 ≦ T2/T1 ≦ 3.0 these relations.

4. discharge lamp as claimed in claim 3 is characterized in that, the wall thickness T 3 of described electrode is under the situation of 0.05mm～0.2mm, and the wall thickness T 1 of described bottom center is 0.2mm ≦ T1 ≦ 1.0mm, and the wall thickness T 2 of described bottom end is 0.5mm ≦ T2 ≦ 2.0mm.