Embodiment
Fig. 1 is the explanation cutaway view of formation summary of an example of expression Excimer lamp 10 of the present invention.Fig. 1 (a) is the cutaway view of expression along the section of the length direction of discharge vessel 20, and Fig. 1 (b) is the cutaway view of the A-A ' line of presentation graphs 1 (a).
This Excimer lamp 10 possesses that two ends are sealed airtightly and the discharge vessel 20 that is formed with the long chi shape of hollow discharge space S, that section is rectangular-shaped in inside.This discharge vessel 20 comprises: the lower wall panels 22 that wainscot 21 reaches with respect to wainscot 21; Be linked to the pair of sidewalls plate 23 of wainscot 21 and lower wall panels 22; And the pair of end wallboard 24 that sealed of the two ends of the cubic cylindrical body that will constitute by these wainscots 21, lower wall panels 22 and pair of sidewalls plate 23.Discharge vessel 20 by the silica glass of transmission vacuum-ultraviolet light well for example synthetic quartz glass form.
In the inside of discharge vessel 20, discharge gas being arranged to enclose as the pressure of 10~80kPa.Use gas as discharge, even select any gas, can be not influential to the metachronism variation of activity yet, but according to the kind of discharge with gas, the centre wavelength of the quasi-molecule light that is radiated is inequality.For example, inclosure has the Excimer lamp of xenon (Xe) to produce with the quasi-molecule light of 172nm as centre wavelength, there are the argon (Ar) and the Excimer lamp of the mist of chlorine (Cl) to produce and enclose with the quasi-molecule light of 175nm as centre wavelength, inclosure has the krypton (Kr) and the Excimer lamp of the mist of iodine (I) to produce with the quasi-molecule light of 191nm as centre wavelength, there are the argon (Ar) and the Excimer lamp of the mist of fluorine (F) to produce in inclosure with the quasi-molecule light of wavelength 193nm as centre wavelength, inclosure has the krypton (Kr) and the Excimer lamp of the mist of bromine (Br) to produce with the quasi-molecule light of 207nm as centre wavelength, inclosure has the krypton (Kr) and the Excimer lamp of the mist of chlorine (Cl) to produce with the quasi-molecule light of 222nm as centre wavelength, and enclosing has the xenon (Xe) and the Excimer lamp of the mist of chlorine (Cl) to produce with the quasi-molecule light of 308nm as centre wavelength.
Outer surface at the wainscot 21 of discharge vessel 20 possesses high voltage supplying electrode 11, possesses grounding electrode 12 at the outer surface of lower wall panels 22, and these electrodes 11,12 are configured to toward each other.Kind electrode 11,12 becomes reticulated structure, from transmissive light between the mesh.As material, for example use aluminium, nickel, gold etc., for example the method by wire mark or vacuum evaporation forms.In addition, each electrode 11,12 is connected to suitable high frequency electric source (not shown).
In above-mentioned Excimer lamp 10, in order to utilize the vacuum-ultraviolet light that is produced by quasi-molecule discharge efficiently, be provided with the ultraviolet reflecting layer 30 that constitutes by fine particle at inner surface with respect to the discharge space S of discharge vessel 20.This ultraviolet reflecting layer 30 is made of accumulation body A31 and accumulation body B32.Accumulation body A31 is formed at the part towards the inner surface of discharge space S of the discharge vessel 20 that is provided with high voltage supplying electrode 11, promptly is formed at and the inner surface of wainscot 21 and a part corresponding zone of high voltage supplying electrode 11.In addition, accumulation body B32 is formed at the part towards the inner surface of discharge space S of the discharge vessel 20 that is not provided with high voltage supplying electrode 11 or grounding electrode 12, promptly is formed at the arbitrary region the inner surface of the inner surface of the wainscot 21 that departs from from the zone corresponding with electrode 11,12 and lower wall panels 22 and sidewall paneling 23 and front sheet 24.That is, the ultraviolet reflecting layer 30 that is formed on the zone corresponding with high voltage supplying electrode 11 of inner surface of wainscot 21 is called accumulation body A31, and other regional ultraviolet reflecting layer 30 that will be formed at discharge vessel 20 inner surfaces is called accumulation body B32.
On the other hand, do not form ultraviolet reflecting layer 30, constitute the light injection part thus at the lower wall panels 22 of discharge vessel 20 and grounding electrode 12 corresponding inner surfaces.
The thickness of accumulation body A31 is for example 5~1000 μ m, is made of silicon dioxide granule and the melting point fine particle than silicon dioxide height and transmitting UV.Melting point has for example aluminium oxide, lithium fluoride, magnesium fluoride, calcirm-fluoride, barium fluoride etc. than the fine particle of silicon dioxide height and transmitting UV.
Vacuum-ultraviolet light is incident upon this accumulation body A31, and then a part is in the surface reflection of fine particle, and another part is refraction and at the particle internal transmission, and once more in other surface reflection or refraction.In a plurality of fine particles, carry out this reflection, refraction repeatedly, thereby vacuum-ultraviolet light is by scattered reflection.
Yet, the heat fusion of the plasma that silicon dioxide granule is produced because of Excimer lamp 10, crystal boundary disappears, can't the scattered reflection vacuum-ultraviolet light, reduce reflectivity.Especially, the accumulation body A31 that is formed on the zone corresponding with high voltage supplying electrode 11 is the heat that is subjected to plasma easily, constitutes the easy fusion of silicon dioxide granule of accumulation body A31.On the other hand, though the melting point fine particle higher than silicon dioxide be exposed to plasma pine for can fusion yet.Therefore, in accumulation body A31, sneak into the melting point fine particle higher than silicon dioxide, the fine particle that is adjacent to each other combination to each other, thus can prevent that crystal boundary from disappearing, the reflectivity that can suppress accumulation body A31 descends.
The thickness of accumulation body B32 for example is 10~1000 μ m, is made of the fine particle that contains silicon dioxide granule.The fine particle that constitutes accumulation body B32 can only be made of silicon dioxide granule, also can contain the material that other combine with oxygen, and be mixed with the insulating properties fine particle that the material by transmitting UV constitutes, for example aluminium oxide, lithium fluoride, magnesium fluoride, calcirm-fluoride, barium fluoride.
Even vacuum-ultraviolet light is incident upon accumulation body B32, also on a plurality of fine particles, produce reflection, refraction repeatedly, thus vacuum-ultraviolet light scattered reflection.In addition, accumulation body B32 is formed at the inner surface of the discharge vessel 20 beyond the zone corresponding with electrode 11,12, thereby is not easy to be subjected to the influence of the heat of plasma.Therefore, even only constitute accumulation body B32, also be not easy to produce the fine particle of adjacency to each other in conjunction with caused crystal boundary disappearance by silicon dioxide granule.
Fine particle is the particle of particle footpath in the scope of for example 0.01~20 μ m as giving a definition, medium particle diameter (maximum of the particle size distribution of number benchmark) is for example preferred 0.1~10 μ m in accumulation body A31, more preferably 0.1~3 μ m, and at for example preferred too 0.1~20 μ m of accumulation body B32.
Be meant in this what is called " particle footpath ", will be for the surface of ultraviolet reflecting layer 30 about centre position of thickness direction on the sectility face during towards the vertical direction sectility as range of observation, (SEM) obtains the enlarging projection image by scanning electron microscopy, and interval Fu Leite (Feret) diameter of these parallel lines when clipping any particle in this enlarging projection image with two parallel lines of certain orientation.
In addition, " medium particle diameter " is meant, to for example be divided into a plurality of zones as the particle scope directly of the maximum in the particle of above-mentioned resulting each particle footpath and minimum value with the scope of 0.1 μ m, for example be distinguished into about 15 zones, belong to the central value of each regional particle number (number of degrees) for maximum zone.
In this Excimer lamp 10, light a lamp supply of electric power when high voltage supplying electrode 12, can produce the quasi-molecule discharge via discharge vessel 20 at the discharge space S of 11,12 at two electrodes.Thus, form quasi-molecule, and from this excimers radiation vacuum-ultraviolet light.In the direct lower wall panels through having the light injection part 22 and penetrating of the part of the vacuum-ultraviolet light that discharge space S produced to outside.In addition, another part vacuum-ultraviolet light, penetrates towards the outside through the light injection part in ultraviolet reflecting layer 30 diffusion radiations towards the direction radiation of wainscot 21.
The fine particle that constitutes ultraviolet reflecting layer 30 has the particle footpath with vacuum ultraviolet (VUV) light wavelength same degree, thus scattered reflection vacuum-ultraviolet light effectively.
Yet, when long-term lighting possesses the Excimer lamp 10 of above-mentioned ultraviolet reflecting layer 30, can't keep initial illumination, along with the time illumination of lighting a lamp descends gradually.The inventor analyzes the reason that illumination reduces from all aspects, consider whether can be the reflectivity decline of the ultraviolet reflecting layer 30 of one of its principal element.
Therefore, measure the reflected intensity spectrum of the ultraviolet reflecting layer 30 of the reflected intensity spectrum of ultraviolet reflecting layer 30 of the initial Excimer lamp 10 of lighting a lamp and the Excimer lamp 10 after the long-term lighting, relatively resolve both.Learnt that by this result the ultraviolet reflecting layer 30 of the Excimer lamp 10 after long-term lighting produces absorption band at ultraviolet region, a ultraviolet part is absorbed by ultraviolet reflecting layer 30, reduces thereby produce illumination.
The generation reason of the ultraviolet region absorption band of ultraviolet reflecting layer 30 is, the silicon dioxide granule that constitutes ultraviolet reflecting layer 30 exposes to the open air in discharge in ultraviolet ray or plasma, be subjected to radiation insult (radiation damage), produce the internal flaw of the light that absorbs the ultraviolet region wavelength, ultraviolet ray is absorbed by internal flaw, makes scattered reflection be suppressed.Internal flaw is meant, the Si-O-Si key of silicon dioxide granule expose to the open air in ultraviolet ray or plasma and produce, near the Si-Si defective that has absorption edge the wavelength 163nm or near wavelength 215nm, have an absorption band the E ' heart (E ' center) (Si).
Because above-mentioned, produce the light that absorbs the ultraviolet region wavelength internal flaw be silicon dioxide granule, the internal flaw of silicon dioxide granule is depended in the light absorption that becomes the ultraviolet region wavelength of the reason that illumination reduces.In addition, can not produce radiation insult even be exposed in ultraviolet ray or the plasma at the fine particle of transmitting UVs formation, except silicon dioxide granule such as aluminium oxide, lithium fluoride, magnesium fluoride, calcirm-fluoride, barium fluoride yet.Therefore, by preventing in the silicon dioxide granule that constitutes ultraviolet reflecting layer 30, to produce internal flaw, can suppress illumination and reduce, even long-term lighting also can keep high illumination sustainment rate.
In order to prevent in silicon dioxide granule, to produce internal flaw, make silicon dioxide granule contain the OH base just effectively.By containing the OH base, can be suppressed in the contained silicon dioxide granule of ultraviolet reflecting layer 30 and generate internal flaw, can prevent to reduce the reflectivity of ultraviolet reflecting layer 30.
Below, the formation method of the ultraviolet reflecting layer that fine particle constituted 30 that contains the silicon dioxide granule that comprises the OH base is illustrated.Ultraviolet reflecting layer 30 is by for example being called the method for " flowing down method (flow down) ", forms the presumptive area of the inner surface of material at discharge vessel, forms the build-up of particles layer that contains silicon dioxide granule.For example, made up water and PEO resin (polyethylene oxide: mix fine particle in stickiness solvent polyethylene glycol oxide) and adjust dispersion liquid, this dispersion liquid is flow to discharge vessel form in the material having.In addition, dispersion liquid is attached to after the presumptive area of discharge vessel formation material inner surface, drying, calcining make water and the evaporation of PEO resin, can form the build-up of particles layer thus.At this, calcining heat is for example 500 ℃~1100 ℃.
As making silicon dioxide granule contain an example of the method for OH base, by supply steam and with electric furnace the silicon dioxide granule that does not contain the OH base is heated (for example 1000 ℃), make the silicon dioxide granule that contains a large amount of OH bases.By using silicon dioxide granule, can form the ultraviolet reflecting layer that fine particle constituted 30 that contains the silicon dioxide granule that comprises the OH base through this processing.
In addition,, also can the silicon dioxide granule that not contain the OH base be attached to after discharge vessel forms the presumptive area of material inner surface, by supply steam and calcine, make silicon dioxide granule contain the OH base as other method.In addition, also can make the silicon dioxide granule that does not contain the OH base after forming ultraviolet reflecting layer 30,, make silicon dioxide granule contain the OH base by supplying steam again and heating with electric furnace through calcining.
In addition, also can contain the OH base according to its method for making, but the OH of some product base concentration is lower, thereby preferably contains the OH base of high concentration by said method by buying available silicon dioxide granule.
About the concentration of the contained OH base of silicon dioxide granule,, the contained OH concentration of silicon dioxide granule that constitutes ultraviolet reflecting layer 30 can be adjusted to arbitrary value by selecting various thermal exhaust conditions.For example, be constant even keep temperature, along with the prolongation of retention time, can remove more OH base.Consider the amount that contains in advance in the OH of silicon dioxide granule base,, just can form the ultraviolet reflecting layer that fine particle constituted 30 of the silicon dioxide granule that contains any OH base concentration by the amount that thermal exhaust adjustment is removed the OH base.
Represent 1st experiment relevant with Excimer lamp.
According to the formation shown in Fig. 1 (a) and (b), make the Excimer lamp that possesses ultraviolet reflecting layer.
[basic comprising of Excimer lamp]
The material of discharge vessel is a silica glass, is of a size of 15mm * 43mm * 350mm, thickness is 2.5mm.
The size of high voltage supplying electrode and grounding electrode is 30mm * 300mm.
Ultraviolet reflecting layer by with the silicon dioxide granule of medium particle diameter 1.5 μ m proportionately proportion by subtraction 90 weight %, with the aluminium oxide particles of medium particle diameter 1.5 μ m proportionately the mixture that mixes of proportion by subtraction 10 weight % constitute, form respectively by flowing down method, calcining heat is 1000 ℃.
As discharge gas, xenon is enclosed in the discharge vessel with 40kPa.
To OH base concentration, reflection sustainment rate and the illumination sustainment rate in the Excimer lamp mensuration silicon dioxide granule with above-mentioned formation.Cut from discharge vessel and to get all ultraviolet reflecting layers, use the thermal desorption spec-troscopy (TDS) analytic approach to measure.Thus, calculate OH base concentration in the contained silicon dioxide granule of ultraviolet reflecting layer.In addition, obtain the composition ratio of being cut the contained silicon dioxide granule of the ultraviolet reflecting layer got, by composition than calculating the weight of OH base with respect to silicon dioxide granule.In addition, use vacuum-ultraviolet light light-dividing device (VUV), ultraviolet illumination photometry device, measure ultraviolet reflecting layer after lighting a lamp continuously in 500 hours with respect to the reflection sustainment rate and the illumination sustainment rate of initial condition.
The measurement result of lamp 1~5 is shown in table 1.
[table 1]
|
OH base concentration (wtppm) in the silicon dioxide granule |
Reflection sustainment rate (%) |
Illumination sustainment rate (%) |
Lamp 1 |
5 |
78 |
72 |
Lamp 2 |
7 |
82 |
79 |
Lamp 3 |
10 |
98 |
96 |
Lamp 4 |
42 |
96 |
92 |
Lamp 5 |
132 |
96 |
94 |
Fig. 2 is a chart of the base concentration of the OH in the silicon dioxide granule in the measurement result shown in the table 1 (wtppm) being described the numerical value of lamp 1~5 as transverse axis, reflection sustainment rate (%) as the longitudinal axis.
In addition, Fig. 3 is a chart of the OH base concentration (wtppm) in the vertical silicon dioxide granule of the measurement result shown in the table 1 being described the numerical value of lamp 1~5 as transverse axis, illumination sustainment rate (%) as the longitudinal axis.
In addition, the chart that is shown in Fig. 2 and Fig. 3 is that transverse axis is single logarithm chart of logarithmic scale.
Be may be read into by above result: OH in silicon dioxide granule base concentration is during less than 10wtppm, and reflection sustainment rate and illumination sustainment rate are all low, and during the long-term lighting Excimer lamp, disposal ability descends.On the other hand, OH in silicon dioxide granule base concentration becomes 10wtppm when above, and reflecting sustainment rate and illumination sustainment rate all becomes more than 90%, even the long-term lighting Excimer lamp also can be kept disposal ability.As shown in Figures 2 and 3 as can be known, OH base concentration is by becoming 10wtppm less than 10wtppm when above, reflection sustainment rate and illumination sustainment rate all can uprise sharp, therefore making OH base concentration in the silicon dioxide granule reach 10wtppm can there were significant differences when above, keeps the effect of performance excellence aspect the illumination when long-term lighting.
Yet even the OH base concentration that will constitute in the silicon dioxide granule of ultraviolet reflecting layer 30 makes more than the 10wtppm, also producing in the Excimer lamp with 172nm is the lower situation of illumination of the quasi-molecule light of centre wavelength.In addition, in the lighting a lamp of the Excimer lamp 10 of enclosing xenon as discharge with gas, exist the color of the discharge that produces among the discharge space S to become green situation, confirm to have produced the molecule (XeO) that xenon atom combines with oxygen atom institute, and by this molecule radiate with near the 550nm as the green light of centre wavelength.
In addition, when constituting in the discharge plasma that the contained OH base of silicon dioxide granule of ultraviolet reflecting layer 30 generates exposing to the open air in discharge space, be heated and will be with water (H
2O) be discarded in the discharge space S for the foreign gas of main component.Be that to decompose the oxygen atom that produces in plasma be to be discarded to discharge space S from the contained OH base of silicon dioxide granule that constitutes ultraviolet reflecting layer 30 for the foreign gas of main component with water.
When the inner surface of discharge vessel 20 is formed with the ultraviolet reflecting layer 30 that is made of fine particle because the concavo-convex of fine particle arranged, thereby surface area ratio not to be formed with the surface of smooth discharge vessel 20 of ultraviolet reflecting layer 30 big.Foreign gas is to be emitted and produced by the ultraviolet reflecting layer 30 that exposes to the open air in discharge plasma, thereby produces more foreign gas when being formed with ultraviolet reflecting layer 30.In addition, because the volume of a particle is little, thereby the fine particle that constitutes ultraviolet reflecting layer 30 compares with discharge vessel 20, and thermal capacitance is less.So,, also become high temperature and emit foreign gas easily even in the short time that produces about several 10ns of discharge plasma, heat.
Accumulation body A31 is the zone corresponding with high voltage supplying electrode 11 that is formed at wainscot 21 inner surfaces, thereby directly is exposed at 11,12 discharge plasmas that produced of electrode, so be heated foreign gas is discarded in the discharge space S.
On the other hand, accumulation body B32 is formed at the wainscot 21 that departs from from high voltage supplying electrode 11 or the inner surface of the lower wall panels 22 that departs from from grounding electrode 12, or be formed at any zone of sidewall paneling 23 or front sheet 24 inner surfaces, though thereby, can directly not be exposed at 11,12 discharge plasmas that produced of electrode towards discharge space S.So, think can produce foreign gas hardly from accumulation body B32.On the contrary, think that accumulation body B32 adsorbs foreign gas, by this situation of following experiment susceptible of proof.
As the 2nd experimental subjects, the inner surface that is produced on discharge vessel 20 only is formed with accumulation body B and does not form the Excimer lamp of accumulation body A.Use xenon as discharge gas, and when the inclosure discharge is with gas, also sneak into oxygen, will enclose the Excimer lamp of aerobic in advance as foreign gas as experimental subjects.The oxygen concentration that is enclosed in discharge space S is 160wtppm, and discharge is 40kPa with the pressure of gas.When sneaking into aerobic as foreign gas, the influence that illumination is descended with the rare gas reaction is very big, can produce the discharging light of wavelength 550nm in addition, differentiates oxygen thus easily and sneaks into discharge space S.
Preparation has the 3 kind Excimer lamps of the particle composition of formation fine particle than accumulation body B inequality at the inner surface of discharge vessel.Lamp 1 possesses the accumulation body B that is only made by silicon dioxide granule, and lamp 2 possesses the accumulation body B that is made of silicon dioxide granule and aluminium oxide particles, and lamp 3 possesses the accumulation body B that is made of silicon dioxide granule and calcirm-fluoride particle.In addition, as a comparative example, prepare not to be formed with the lamp 4 of accumulation body B.Each lamp is measured the luminous intensity of the 550nm after lighting a lamp continuously 15 minutes till the quasi-molecule discharge stability, and with it as " the 550nm luminous intensity at the initial stage of lighting a lamp ".Afterwards, continue the Excimer lamp of lighting a lamp, measure the 550nm luminous intensity after lighting a lamp continuously 5 hours, with it as " the 550nm luminous intensity after lighting a lamp 5 hours ".
[table 2]
The 2nd experimental result is shown in table 2.The numerical value of " the 550nm luminous intensity after lighting a lamp 5 hours ", be will " the 550nm luminous intensity at the initial stage of lighting a lamp " numerical value as 100 o'clock relative value.In possessing lamp 1~lamp 3 of accumulation body B, the numerical value of the 550nm luminous intensity after lighting a lamp 5 hours is reduced to below 100, and with the preliminary phase ratio of lighting a lamp, the quantity of the molecule (XeO) that xenon atom combines with oxygen atom institute reduces.That is, the oxygen of sneaking in advance in the discharge space reduces.On the other hand, in the lamp 4 that is not formed with accumulation body B, the numerical value of the 550nm luminous intensity after lighting a lamp 5 hours still keeps 100, and the amount of sneaking into the oxygen in the discharge space does not as can be known in advance change.Thus, at the inner surface of the discharge vessel of Excimer lamp the light that accumulation body B just can reduce 550nm is set, oxygen is adsorbed by accumulation body B as can be known.In addition, accumulation body B is not exposed to discharge plasma, and therefore adsorbed foreign gas can not be discarded to discharge space.
Below, whether the phenomenon that is attracted to accumulation body B for the oxygen of confirming affirmation in the 2nd experiment is to produce according to lighting a lamp of Excimer lamp, carries out the 3rd experiment.To have with lamp 1~3 same lamp 5~7 that constitutes of the 2nd experimental subjects and test as the 3rd.In addition, as a comparative example, prepare not to be formed with the lamp 8 of accumulation body B.Each lamp is measured the luminous intensity of the 550nm after lighting a lamp continuously 15 minutes, with it as " the 550nm luminous intensity at the initial stage of lighting a lamp ".Then, place down with the state of not lighting a lamp and to light a lamp after 48 hours, measure the luminous intensity of the 550nm that lit a lamp continuously 15 minutes, with it as " through the 550nm luminous intensity after 48 hours ".Afterwards, continue lighting a lamp of Excimer lamp, measure the 550nm luminous intensity after lighting a lamp continuously 5 hours, with it as " through the 550nm luminous intensity after lighting a lamp 5 hours after 48 hours ".
[table 3]
The 3rd experimental result is shown in table 3." through the 550nm luminous intensity after 48 hours " reaches the numerical value of " through the 550nm luminous intensity after lighting a lamp 5 hours after 48 hours ", be will " the 550nm luminous intensity at the initial stage of lighting a lamp " value as 100 o'clock relative value.In possessing lamp 5~lamp 7 of accumulation body B, be 100 with respect to value through the 550nm luminous intensity after 48 hours, be reduced to 10~11 through the value of the 550nm luminous intensity after lighting a lamp 5 hours after 48 hours, the Excimer lamp of lighting a lamp as can be known just can reduce oxygen.Be adsorbed in the principle of accumulation body B as oxygen,, produced the ultraviolet ray that produces by lighting a lamp and made oxygen produce the chemisorbed that chemical reaction is adsorbed on the fine particle surface of accumulation body B.
On the other hand, in the lamp 8 that does not form accumulation body B, all still keep 100, thereby the amount of sneaking into the oxygen in the discharge space does not as can be known in advance change through the 550nm luminous intensity after 48 hours and through the value of the 550nm luminous intensity after lighting a lamp 5 hours after 48 hours.
The fine particle that constitutes accumulation body B is to be exposed to the surface adsorption foreign gas of discharge space, thereby towards the surface area of the discharge space adsorbable more foreign gas that heals more greatly.Therefore, the surface area summation of all contained particles is bigger in the powder of " specific area " that is Unit Weight, and adsorbable more foreign gas heals.Specific area is for example to measure by the following assay method that is called as the BET method: adsorb the molecular gas (for example nitrogen) of known occupied area on the surface of fine particle in advance, obtain specific area by its amount.When measure constituting the specific area of fine particle of accumulation body B, the surface that accumulation body B is exposed to discharge space is exposed to molecular gas and adsorbs, and obtains specific area by its amount.
Below, the 4th experiment that expression is carried out in order to confirm effect of the present invention.
<experimental subjects 〉
According to the formation that is shown in Fig. 1 (a) and (b), make the Excimer lamp that possesses accumulation body A and accumulation body B.
[basic comprising of Excimer lamp]
The material of discharge vessel is a silica glass, is of a size of 15mm * 43mm * 540mm, and thickness is 2.5mm.
The size of high voltage supplying electrode and grounding electrode is 32mm * 500mm.
The size of area relative light injection part that does not form accumulation body B on lower wall panels is 36mm * 504mm than the big 2mm of grounding electrode.
Accumulation body A and accumulation body B form respectively by flowing down method, and calcining heat is 1000 ℃.
After carrying out the thermal exhaust of 1 hour (time after the intensification) under 800 ℃ of conditions, in discharge vessel, enclose xenon.Its enclosed volume is 40kPa.
The OH base content of the accumulation body A of the lamp of made is 500wtppm.
As shown in table 4, at the formation of accumulation body A, prepare formation (1-1), constituted (1-2), constituted (1-3), constituted (1-4) these 4 kinds.4 kinds to be formed in material, particle footpath, medium particle diameter, composition more identical than the aspect, but the area that is provided with that is formed at the accumulation body A on the zone corresponding with the high voltage supplying electrode of upper wall panel inner surface changes to 160cm
2, 128cm
2, 107cm
2, 40cm
2The amount that is released to the foreign gas in the discharge space depends on the area that is provided with of accumulation body A, and therefore as constituting shown in (1-1), accumulation body A is provided with area more greatly, the amount of foreign gas the more, and as constituting shown in (1-4), accumulation body A that area is set is littler, the amount of foreign gas can tail off.In addition, constituting (1-2), constitute (1-3), constituting in (1-4), the area that is provided with that is formed with accumulation body A is 160cm than the area that is formed with the high voltage supplying electrode
2Little, thereby be not on the whole zone of the inner surface of the discharge vessel that is provided with the high voltage supplying electrode, to be formed with accumulation body A, but be formed with accumulation body A in its part.
[table 4]
In addition, as shown in table 5, at the formation of accumulation body B, also prepare formation (2-1), constituted (2-2), constituted (2-3), constituted (2-4) these 4 kinds.Formation (2-1), formation (2-2), formation (2-3) only are made of silicon dioxide granule, are made of silicon dioxide granule and aluminium oxide particles and constitute (2-4).Constitute (2-1), constitute (2-2), constitute (2-3) particle footpath, specific area is made 16 * 10 by the change silicon dioxide granule
4Cm
2/ g, 4 * 10
4Cm
2/ g, 1 * 10
4Cm
2/ g does not wait.In addition, the specific area of formation (2-4) is 4 * 10
4Cm
2/ g.The bigger absorption of the specific area of accumulation body B foreign gas the more, thereby as constituting shown in (2-1), the specific area of accumulation body B is bigger bigger towards the surface area of discharge space, thereby the amount of infiltrating the foreign gas in the discharge space is along with a lantern festival reduces, and as constituting shown in (2-3), the specific area of accumulation body B is littler, infiltrates the interior foreign gas of discharge space along with the quantitative change of the minimizing of lighting a lamp is little.
[table 5]
For the accumulation body A that constitutes (1-1), preparing accumulation body B is to constitute the lamp of (2-1)~formation (2-4) as experimental subjects.In addition, for each combination, prepare 5 kinds of lamps that area is set of change accumulation body B.Similarly, for the accumulation body A that constitutes (1-2), formation (1-3), formation (1-4), prepare accumulation body B for constituting the lamp of (2-1)~formation (2-3).
To each Excimer lamp of formation like this, become 0.6W/cm at the tube wall of discharge vessel load
2Condition under light a lamp, measure the wavelength 150nm~200nm wavelength region may after lighting a lamp continuously 15 minutes xenon excimer light illumination and under constant tube wall load, lit a lamp continuously in 500 hours after the illumination of xenon excimer light of wavelength 150nm~200nm wavelength region may.With the illumination after lighting a lamp continuously 15 minutes as initial illumination, and with the illumination after lighting a lamp continuously in 500 hours with respect to the value of initial illumination as the illumination sustainment rate, calculate [(500 hours light a lamp after illumination)/(illumination after just having lit a lamp)] (%) as " 500 hours illumination sustainment rates ".The reason that is provided with 500 hours is as follows.The illumination that is caused by foreign gas reduces and continues to 500 hours, and illumination can not reduce afterwards, so the contained foreign gas of ultraviolet reflecting layer all emits when till 500 hours, and can not emit afterwards.
As the specification of product, require the illumination more than 80% to keep, thereby be 80% to be judged as " zero " when above, and 500 hours illumination sustainment rates are 80% to be judged as " * " when following 500 hours illumination sustainment rates.
As shown in Figure 4, illumination photometry is following carrying out: fixing Excimer lamp 10 on the ceramic brace table 41 that is disposed at aluminium vessel 40 inside, and position at the surperficial 1mm of distance Excimer lamp 10, with the fixing ultraviolet illumination photometry device 42 of the mode relative with Excimer lamp 10, under the state of the internal atmosphere of replacing aluminium vessel 40 with nitrogen, 11,12 ac high voltages that apply 5.0kV of electrode at Excimer lamp 10, produce discharge in the inside of discharge vessel 20 thus, mensuration is via the illumination of the vacuum-ultraviolet light of the mesh radiation of grounding electrode 12.
Experimental result is shown in Fig. 5 and Fig. 6.By this result, in each combination of the formation of the formation of accumulation body A and accumulation body B, extracts 500 hours illumination sustainment rates and is the combination that area becomes minimum that is provided with of accumulation body B in the Excimer lamp more than 80%.For example, select lamp 3 in the combination that constitutes " constituting (2-1) " that constitutes " constituting (1-1) ", accumulation body B of accumulation body A.Equally, select lamp 8, lamp 13, lamp 18 etc.
At the combination of extraction like this, the formation of accumulation body A, the formation of accumulation body B, the specific area of accumulation body B, the area that is provided with of accumulation body B are listed in table 6.
[table 6]
Fig. 7 is the result's of expression table 6 a chart.With the specific area (* 10 of transverse axis as accumulation body B
4Cm
2/ g), the longitudinal axis is provided with area (cm as accumulation body B
2), indicate numerical value respectively by the formation of accumulation body A.
Table 6 and Fig. 7 represent that the bigger required area that is provided with of illumination reduction that suppresses of specific area diminishes.Constitute at each of accumulation body A,, respectively area is set and specific area is proportional promptly at constituting (1-1), constitute (1-2), constituting (1-3).But in the Excimer lamp with the accumulation body A that constitutes (1-4), even increase specific area, it is also can not become to compare 10cm that area is set
2Low value.
In Excimer lamp with the accumulation body A that constitutes (1-4), compare with the internal volume of discharge vessel, accumulation body B that area is set is too small, thereby diffuse to the probability step-down that foreign gas in the discharge space arrives accumulation body B, can't show adsorption effect.That is,, there is the required MIN area of accumulation body B with respect to the size of discharge space.The size of discharge space is represented with the internal surface area of discharge vessel this moment, internal surface area was about 500cm
2, with respect to this, the area that is provided with of accumulation body B is 10cm
2Therefore, be that the area that is provided with of the required accumulation body B of minimum is 0.02 times of discharge vessel internal surface area.
Below, each of the accumulation body A of derived graph 7 constitutes slope and the intercept that promptly constitutes (1-1), formation (1-2), constitutes each near linear of (1-3).With this result be accumulation body A formation, accumulation body A area is set, the specific area of accumulation body B is listed in table 7 with the specific area of the slope that the relation of area is set, accumulation body B with the intercept that the relation of area is set.
[table 7]
The formation of accumulation body A |
Accumulation body A is provided with area (cm
2)
|
The specific area of accumulation body B and the slope (* 10 that the relation of area is set
-4g)
|
The specific area of accumulation body B and the intercept (cm that the relation of area is set
2)
|
Constitute (1-1) |
160 |
-0.81 |
56 |
Constitute (1-2) |
128 |
-0.67 |
45 |
Constitute (1-3) |
107 |
-0.52 |
37 |
In Fig. 8, transverse axis is provided with area (cm as accumulation body A
2), with the specific area and slope (* 10 that the relation of area be set of the longitudinal axis as accumulation body B
-4G), indicate the result's of table 7 value.
By chart as can be known, the slope of the specific area of accumulation body B and the relation of establishing area is provided with area (cm with respect to accumulation body A
2) have a proportionate relationship of negative slope.The area that is provided with of accumulation body A is made as a (cm
2) time, the specific area of accumulation body B and the slope that the relation of area is set can be expressed as-5.0 * 10
-7* a.
In Fig. 9, transverse axis is provided with area (cm as accumulation body A
2), with the specific area and intercept (cm that the relation of area be set of the longitudinal axis as accumulation body B
2), and the result's of sign table 7 value.
By chart as can be known, the intercept of the specific area of accumulation body B and the relation of establishing area is provided with area (cm with respect to accumulation body A
2) have a proportionate relationship of positive slope.The area that is provided with of accumulation body A is made as a (cm
2) time, the specific area of accumulation body B can be expressed as 0.35 * a with the intercept that the relation of area is set.
In addition, as shown in Figure 7, the specific area that area and accumulation body B are set of accumulation body B has the proportionate relationship with " specific area of accumulation body B and the slope that the relation of area is set " and " specific area of accumulation body B and the intercept that the relation of area is set " expression.Thus, the area that is provided with accumulation body B is made as b (cm
2), the specific area of accumulation body B is made as c (cm
2/ g) time, the relation of the specific area that area and accumulation body B are set of the accumulation body B of Fig. 5 can be expressed as
B=(specific area of accumulation body B and the slope that the relation of area is set) * c+ (specific area of accumulation body B and the intercept that the relation of area is set)
In addition, by the result of Fig. 8 and Fig. 9, the area that is provided with of accumulation body A is made as a (cm
2) time, the specific area of accumulation body B can be expressed as-5.0 * 10 with the slope that the relation of area is set
-7* a, the specific area of accumulation body B can be expressed as 0.35 * a with the intercept that the relation of area is set, thereby the relation of the specific area that area and accumulation body B are set of the accumulation body B of Fig. 7 can followingly be represented.
b=-5.0×10
-7ac+0.35a
In addition, by the experimental result of Fig. 5 and Fig. 6 as can be known, if accumulation body B that area b is set is bigger than the amount shown in the relation of the specific area that area and accumulation body B are set of the accumulation body B of Fig. 5, then 500 hours illumination sustainment rates are more than 80%, to be judged to be zero.
By above result as can be known, in the Excimer lamp that possesses the accumulation body A that contains the OH base, reduce in order to suppress illumination, the satisfied following relation of area that is provided with of accumulation body B gets final product.
The area that is provided with of accumulation body A is made as a (cm
2), the area that is provided with of accumulation body B is made as b (cm
2), the specific area of accumulation body B is made as c (cm
2/ g) time, for
b≥-5.0×10
-7ac+0.35a
In addition, in Fig. 7, in the Excimer lamp with the accumulation body A that constitutes (1-4), even increase the specific area of accumulation body B, accumulation body B is provided with area and also can become and compare 10cm
2Low value, the specific area of accumulation body B can not become with the relation of establishing area have formations (1-1), constitute (1-2), the situation during the accumulation body A of formation (1-3).So, in table 7 and Fig. 8, Fig. 9, do not consider to have the situation of the accumulation body A that constitutes (1-4).That is, above-mentioned accumulation body B the condition that area should satisfy is set is to get rid of to have the situation of the accumulation body A that constitutes (1-4).Therefore, being provided with in the condition that area should satisfy of accumulation body B, must get rid of situation with the accumulation body A that constitutes (1-4).
Situation with the accumulation body A that constitutes (1-4) is meant, compare with the internal volume of discharge vessel, accumulation body B that area is set is too small, thereby can't show the situation of the effect of absorption.That is, accumulation body B's is provided with about 0.02 times of internal surface area that area reaches discharge vessel.Therefore, reduce, be made as d (cm in internal surface area with discharge vessel in order to suppress illumination
2) time, accumulation body B is provided with area b (cm
2) relation also need to satisfy following condition.
b>0.02d
By above result as can be known, in the Excimer lamp that possesses the accumulation body A that contains the OH base, descend in order to suppress illumination, the formation of accumulation body B must satisfy following relation.The area that is provided with of accumulation body A is made as a (cm
2), the area that is provided with of accumulation body B is made as b (cm
2), the specific area of accumulation body B is made as c (cm
2/ g), the internal surface area of discharge vessel is made as d (cm
2) time, must satisfy
B 〉=-5.0 * 10
-7Ac+0.35a, and b>0.2d.
By satisfying above-mentioned relation, the amount of the foreign gas of being emitted from accumulation body A can not surpass the amount of the adsorbable foreign gas of accumulation body B, and can residual impurity gas at discharge space.Therefore, can suppress oxygen atom contained in the foreign gas combine and caused quasi-molecule light with gas with discharge illumination reduction,, also can suppress the illumination reduction, penetrate vacuum-ultraviolet light effectively even during the long-term lighting Excimer lamp.
In addition, accumulation body A's is provided with area a (cm
2) and accumulation body B area b (cm is set
2) be meant, do not consider the concavo-convex of fine particle, suppose the surface smoothing of accumulation body A or accumulation body B and the value of instrumentation.In addition, the internal surface area d (cm of discharge vessel
2) also be to suppose its surface smoothing and the value of instrumentation.