Excimer lamp
Technical field
The present invention relates to have the Excimer lamp of a pair of transmitance outer electrode, relate in particular to the Excimer lamp that disposes the starting auxiliary electrode at the inner face of discharge vessel at the outer surface of discharge vessel.
Background technology
In the past; Known have in the outer surface arranged opposite pair of external electrodes of discharge vessel and the Excimer lamp that constitutes; The outer electrode that forms in the light emission face place of this discharge vessel in order to bring into play the original function that lets light penetrate, uses and for example gold size is coated with into cancellate transmitance electrode.
On the other hand; As the outer electrode that forms in the outer surface that does not penetrate with a side of the opposed light of above-mentioned light emission face; Though on function, need not to possess transmitance; But in most cases, from the simplification of manufacturing process, and this discharge vessel in the viewpoint of the stability etc. of discharge takes place, still adopt the transmitance electrode with the same former state of above-mentioned light emission face.
With the startability that improves this type of Excimer lamp is purpose, and known have a starting auxiliary electrode that also is made up of conductive material in the setting of discharge vessel inner face.For example, japanese kokai publication hei 11-273629 communique (patent documentation 1) is so, in an end of the pair of external electrodes of being located at the luminous tube outer surface, is provided with the starting auxiliary electrode that is made up of conductive material at this luminous tube inner surface place.And also disclose following content: this starting auxiliary electrode is located between the outer electrode, also can be not necessarily overlapping with two outer electrodes.
Among Fig. 8, illustrate and use the Excimer lamp of transmitance electrode as outer electrode, in the outer surface of discharge vessel 11, arranged opposite has the outer electrode 12 of a pair of transmitance.In an end of this outer electrode 12, be provided with starting auxiliary electrode 13 at the inner surface of discharge vessel 11.
Through such configuration starting auxiliary electrode 13, for example when the outer electrode 12 to a side applies the high-frequency high voltage and lights a lamp, move the startability lifting rapidly to the opposing party's outer electrode via this starting auxiliary electrode through making electric charge.
Yet the discharge between above-mentioned starting auxiliary electrode 13 and the outer electrode 12 not only the time is carried out in starting, still can produce this discharge after lighting a lamp usually moving to, and this phenomenon is as shown in the figure, as the direction transmission of creeping discharge X towards outside electrode 12.
When such generation creeping discharge X, consume the energy of this amount, the required integral energy of the regular discharge between the outer electrode originally reduces, and causes illumination to reduce.
In addition, causing that also the part illumination at the position that this creeping discharge X takes place reduces, is not preferred.
As preventing the such starting auxiliary electrode and the technology of the creeping discharge between the outer electrode, in TOHKEMY 2010-225343 communique (patent documentation 2), disclose the structure that is provided with the dendritic electrode that extends vertically in the end of transmitance electrode.
Should existing example shown in Fig. 9, the end at the transmitance outer electrode 12 of discharge vessel 11 outer surfaces be provided with the dendritic electrode 14 that extends vertically.At the inner face of above-mentioned discharge vessel 11, be provided with the starting auxiliary electrode 13 that constitutes by conductive material, this starting auxiliary electrode 13 is configured to overlap each other via the leading section of above-mentioned dendritic electrode 14 and discharge vessel 11.
In this prior art, form corresponding to the end of this dendritic electrode 14 through making starting auxiliary electrode 13, increase the distance between this outer electrode 12 and the starting auxiliary electrode 13 thus, make the structure that makes that creeping discharge is not easy to produce.
But; Be accompanied by recently to the requirement of the high illuminationization of Excimer lamp and require lamp height inputization further; Even with above-mentioned existing structure; Also existence comes the creeping discharge X of self-starting auxiliary electrode 13 to arrive the situation of outer electrode 12 along dendritic electrode 14, and its influence impacts the regular discharge between the outer electrode 12.In above-mentioned prior art constructions, if will avoid this problem, it is longer to make dendritic electrode 14 extend ground along tube axial direction, but causes the lengthization of lamp total length like this, takes into account effective length of illumination, inappropriate in practicality, can't make us accepting.
Patent documentation 1: japanese kokai publication hei 11-273629 communique
Patent documentation 2: TOHKEMY 2010-225343 communique
Summary of the invention
The present invention is in view of above-mentioned prior art problems; A kind of Excimer lamp is provided; Outer surface at discharge vessel is provided with the pair of external electrodes that at least one side is a transmitance; Dispose starting auxiliary electrode and constituting at above-mentioned discharge vessel inner face, in this Excimer lamp, through the long as far as possible dendritic electrode of creepage distance is set in limited space; Make creeping discharge from above-mentioned starting auxiliary electrode before this dendritic electrode and then can not arrive outer electrode, thereby do not influence the regular discharge between the outer electrode.
In order to solve above-mentioned problem, in this invention, it is characterized by, on the said external electrode, be provided with dendritic electrode, this dendritic electrode comprises: root, the tube axial direction from the axial end of this outer electrode along above-mentioned discharge vessel extends; And branch portion, extend from the front end of this root Width to above-mentioned discharge vessel; Above-mentioned starting auxiliary electrode disposes with the mode that overlaps each other with the branch portion front end of the dendritic electrode of a side said external electrode at least.
And, it is characterized by, the root of above-mentioned dendritic electrode extends along tube axial direction from an end of the Width of said external electrode, and above-mentioned branch portion extends to the other end of the Width of above-mentioned discharge vessel from the front end of this root.
And, it is characterized by, the width of the above-mentioned root of above-mentioned dendritic electrode and the connecting portion of above-mentioned branch portion is bigger than the width of above-mentioned branch portion.
And, it is characterized by, the width of the leading section of the branch portion of above-mentioned dendritic electrode is bigger than the width in the zone beyond the leading section of this one.
The invention effect
According to the present invention; The branch portion that the dendritic electrode that is located on the outer electrode is extended by root that extends along tube axial direction and broad ways constitutes, so the initial creeping discharge that takes place is advanced along this one between the branch portion front end of starting auxiliary electrode and dendritic electrode.To this; Because there is not electrode in the space part connect outer electrode from above-mentioned starting auxiliary electrode straight line,, can not form current potential so do not accumulate electric charge at the glass inner face; So do not produce electric field, the creeping discharge to outside electrode direction do not take place to the space part direction.
And; The root of above-mentioned dendritic electrode is arranged to extend from the end, position of the Width of the end of outer electrode; The length of a portion is risen to greatest extent, the total length of dendritic electrode is obtained bigger, can prevent reliably that creeping discharge from arriving the situation of outer electrode.
And, compare with the branch portion of dendritic electrode, on the coupling part of root and branch portion, width is made greatlyyer, accumulate than multi-charge in the conduct of electrode part than large tracts of land coupling part partly.Thus, the initial creeping discharge that takes place between starting auxiliary electrode and the branch portion front end is easier towards the more connecting portion direction of this electric charge accumulation and the above-mentioned branch in edge portion advances.
In addition, the width of the leading section of the branch portion through increasing dendritic electrode is prone to accumulate electric charge, in this initial creeping discharge of generation easily between the two on the glass inner face between the leading section of starting auxiliary electrode and this wider width.The creeping discharge that this is initial is advanced along branch portion as stated, does not connect the creeping discharge between starting auxiliary electrode and the outer electrode so straight line can not take place.
Like this, need not to make the lamp total length to be long sized, the distance that the lengthening creeping discharge is advanced and make it not arrive outer electrode can not brought dysgenic effect to the original regular discharge between the outer electrode so play.
Description of drawings
Fig. 1 is the stereogram of Excimer lamp of the present invention.
Fig. 2 is the vertical view of Fig. 1.
Fig. 3 is the A-A cutaway view of Fig. 2.
Fig. 4 is the B-B partial sectional view of Fig. 2.
Fig. 5 is the sketch map of the relation between dendritic electrode shown in the presentation graphs 1 and the starting auxiliary electrode.
Fig. 6 is the partial top view of other embodiment.
Fig. 7 is the partial top view of another other embodiment.
Fig. 8 is the vertical view (A) and the cutaway view (B) thereof of prior art.
Fig. 9 is the vertical view of other prior aries.
Description of symbols
1: Excimer lamp
2: discharge vessel
3: outer electrode
4: dendritic electrode
5: root
6: branch portion
6a: leading section
7: the starting auxiliary electrode
8: connecting portion
11: discharge vessel
12: outer electrode
13: the starting auxiliary electrode
14: dendritic electrode
X: creeping discharge
Embodiment
As shown in Figure 1, on the discharge vessel 2 of Excimer lamp 1 of the present invention, the outer electrode 3,3 of a pair of transmitance is arranged in its two sides arranged opposite.
As each later figure of Fig. 2 is shown specifically, on the end of above-mentioned each outer electrode 3, be provided with the roughly dendritic electrode 4 of L word shape.This dendritic electrode 4 comprises root 5 and branch portion 6, and this root 5 extends along tube axial direction from an end of the Width of the discharge vessel 2 of said external electrode 3, another the distolateral extension from the front end of this root 5 towards the Width of discharge vessel 2 of above-mentioned branch portion 6.
Particularly, as as Fig. 3 of the A-A cutaway view of Fig. 2 or as only taking out dendritic electrode and the stereogram that starts auxiliary electrode shown in Figure 5, be provided with the starting auxiliary electrode 7 that constitutes by conductive material at above-mentioned discharge vessel 2 inner faces.And the leading section 6a that this starting auxiliary electrode 7 clips the branch portion 6 of discharge vessel 2 and above-mentioned dendritic electrode 4 disposes overlappingly.
In said structure, when Excimer lamp started, the high-frequency current that puts on a side outer electrode 3 became a kind of capacity coupled state; Pass the dielectric wall that constitutes discharge vessel 2; Outer electrode 3 mobile high-frequency currents to the opposing party discharge easily, and startability improves.
At this moment; The dendritic electrode 4 that is connected in outer electrode 3 is L word shape roughly, and the electric charge that accumulates in starting auxiliary electrode 7 moves along root 5 thereafter along the position that forms dendritic electrode 4, promptly branch portion 6 moves; Become like this along long path movement, just can not arrive outer electrode 3.And, on the path that connects the beeline between starting auxiliary electrode 7 and the outer electrode 3, there is not dendritic electrode, movement of electric charges can't take place therebetween, so between starting auxiliary electrode 7 and outer electrode 3, be difficult to take place creeping discharge.
If be described in further detail, when lamp start, there is electric charge, the formation current potential at inner area with the branch portion 6 opposed glass tubes (discharge vessel 2) of dendritic electrode 4.
Starting auxiliary electrode 7 clips glass and overlapping with the leading section 6a of above-mentioned branch portion 6, and distance therebetween is very little, thus produce highfield, and in this position generation creeping discharge.
If the discharge here finishes, then successively along branch portion 6 to the mode that the direction of root 5 moves, between starting auxiliary electrode 7 and branch portion 6, discharge continuously.That is the mode generation creeping discharge of, moving with branch portion 6 along dendritic electrode 4.
On the other hand, between the leading section 6a and outer electrode 3 of the branch portion 6 of dendritic electrode 4, their short circuits are not linked such dendritic electrode,, can not form current potential so the glass inner face can not accumulate electric charge.Therefore, can not produce electric field, the creeping discharge to these outer electrode 3 directions can not take place at the glass surface that links the rectilinear direction of starting auxiliary electrode 7 and outer electrode 3.
Fig. 6 illustrates other embodiment, and the width of the root 5 of dendritic electrode 4 and the connecting portion 8 of branch portion 6 is bigger than the width of above-mentioned branch portion 6.
Through like this; On the connecting portion with broad area 8, accumulate than multi-charge; The electric field grow of the direction of the connecting portion 8 of starting auxiliary electrode 7 and branch portion 6, the creeping discharge that is taken place between the leading section 6a of this starting auxiliary electrode 7 and branch portion 6 is moved towards the direction of this connecting portion 8 easily.Therefore, more can prevent directly to take place the situation of creeping discharge towards outer electrode 3 from the branch portion 6 of dendritic electrode 4.
In addition, Fig. 7 illustrates another other embodiment, and the width of the leading section 6a of the branch portion 6 of dendritic electrode 4 forms greatlyyer than the width of other area parts.
Through like this, the electric charge of accumulating in this leading section 6a becomes more, and the creeping discharge between this part and the starting auxiliary electrode 7 takes place easily, prevents to discharge to outer electrode 3 from this starting auxiliary electrode 7.
In addition; In the above-described embodiments, the structure that the root 5 that shows dendritic electrode 4 extends along tube axial direction from an end of the Width of outer electrode 3, but might not be defined in the structure of strictly extending from an end; So long as the end of Width, its position can suitably be selected.
Under these circumstances; Only dendritic electrode 4 is being made the L word shape and be formed on the part of the branch portion 6 that Width extends; With the comparison of the dendritic electrode 14 of prior art shown in Figure 9 in, do not change the total length of discharge vessel 2 and can the length that creeping discharge is advanced be obtained bigger.
, shown in above-mentioned embodiment, be preferably through the root 5 of dendritic electrode 4 being arranged to increase the length of a portion 6 to greatest extent from the end extension of the Width of outer electrode 3.
And; Show dendritic electrode 6,6 the two situation about overlapping each other of starting auxiliary electrode 7 and pair of external electrodes 3,3; But not necessarily need overlap each other with both, also can be to be configured with the dendritic electrode 6 overlapping modes with a certain side, and this is identical with above-mentioned prior art 1.
In addition; Show the structure that pair of external electrodes 3 all is the transmitance electrode, but also can be, only the outer electrode of the light emission face side of discharge vessel is made transmitance; And other outer electrodes are not transmitances, promptly, can be so-called tabular (ベ タ shape) electrodes yet.
As described above; In Excimer lamp of the present invention; In the end of the transmitance outer electrode of discharge vessel outer surface, the dendritic electrode that is made up of root and branch portion is set, and at the discharge vessel inner face; To dispose the starting auxiliary electrode with the branch portion overlapped mode of front end of the dendritic electrode of a side said external electrode at least; The creeping discharge that takes place between starting auxiliary electrode and the branch portion front end is moved along this one, can not make discharge along the straightaway of outer electrode direction, so can not bring harmful effect to the regular discharge between the outer electrode.