CN209260185U - A kind of vacuum coating equipment - Google Patents

Abstract

The utility model discloses a kind of vacuum coating equipments, comprising: vacuum chamber, setting in the indoor optical filter work rest of vacuum and are arranged in the indoor thin-film material evaporation source of vacuum；It is provided with a pair of electrodes between thin-film material evaporation source and optical filter work rest and at optical filter work rest, a pair of electrodes is electrically connected with the ac high voltage source being arranged in outside vacuum chamber.The utility model is by setting a pair of electrodes, and when being evaporated in vacuo thin-film material, apply ac high voltage to electrode: frequency 50Hz, voltage are 3.2~3.6KV.Thin-film material is made of high-index material zinc sulphide and low-index material ice crystal, and implements evaporation by electron beam evaporation source and resistance heating evaporation source respectively.Ac high voltage is applied in high vacuum evaporation film using utility model vacuum coating equipment, to obtain the excellent Thin Film Filter of optics in low temperature substrates, machinery, chemical property.

Description

A kind of vacuum coating equipment

Technical field

The utility model relates to photoelectric instruments and laser device technical field, and in particular to a kind of vacuum coating equipment.

Background technique

Thin Film Filter is widely used in various photoelectric instruments and laser device.In order to obtain better optical, machinery, chemistry The optical filter of performance, the prior art often use electron beam evaporation high-temperature oxide dura mater material in the substrate of 100~350 DEG C of temperature Material is to prepare Thin Film Filter；More advanced technology of preparing is then to be steamed in thin film evaporation deposition process using high-energy ion bombardment Molecule or atom are sent out, the energy that energetic ion carries is conveyed to vapor molecule or atom by momentum transmitting, makes to deposit molecule Or its mobility is greatly increased after the additional kinetic energy of atom acquisition, so that the gather density of film had not only been improved, but also improvement membrane stress, Adhesion property and the dura mater etc. for increasing film, here it is very widely used today ion beam assisted deposition technologies, it is high for preparation Optical stability and high securely durable membrane provide splendid condition.

Unfortunately, its substrate cannot heat when prepared by a small number of Thin Film Filters, such as some optical plastic substrates Temperature cannot be greater than 70 DEG C, What is more, and temperature when some high-precision optical parts and photoelectric device plated film is necessarily less than 50 DEG C, in these cases, even if plated film substrate does not heat, electron beam evaporation source can be generated largely when due to high-temperature material evaporation Heat radiation, equally, energetic ion source can also generate the radiation of a large amount of heat, and causing base reservoir temperature is more than 70 DEG C, especially When the number of plies of optical filter is more, film thickness is larger, temperature even can rise to 100 DEG C or so, cause substrate damage.

On the other hand, even if film engineer tries base reservoir temperature can be controlled to 50 DEG C hereinafter, still at this moment obtaining Thin Film Filter performance be it is very poor, be mainly manifested in: one, film layer gather density is very low.Since film layer is loose, inside has largely Air-gap, so film layer characteristic can change with the relative humidity in air.A large amount of water when relative humidity is higher, in air Impervious, since the refractive index 1.33 of water is higher than air refraction 1.0, increases film layer mean refractive index into film layer, conversely, Make the reduction of film layer mean refractive index, causes film optical properties to drift about with relative humidity, this phenomenon is frequently referred to optics not Stability.Two, oligomeric collection density thin film generates tensile stress.In general, the gather density of film is lower, and tensile stress is bigger.Cause Optical filter is multilayer film composition, therefore eventually leads to very high tie and tire out tensile stress.Tensile stress does not only result in substrate deformation, but also The firmness of film layer can be destroyed.Three, substrate and film layer interface adhesion are poor.Adhesive force between substrate and film layer be by substrate with What strong resultant force between film layer determined, since attachment appears in two kinds of material surfaces, it and substrate and the respective table of film layer Face can be related, and two kinds of material cohesions of high surface energy are larger, and two kinds of material cohesions of low-surface-energy are smaller, high-temperature oxide Dura mater material has a high surface energy, but it evaporating temperature is very high in the preparation, cause substrate to be brought rapidly up, and sulfide, fluorination The soft film materials evaporating temperature such as object is low, though it is small to heat up when preparation, its surface can be lower.Similarly, high refractive index layer and low folding The adhesive force for penetrating rate film layer interface is also similar to substrate-film interface.Four, film hardness reduces.Rise for limitation base reservoir temperature, Forcing finally substantially reduces film hardness in addition its low gather density, high tensile stress and adhesion are poor using soft film material. Similarly, there are also five, chemical stabilities to decline.The above 5 points optics that will seriously affect optical filter, mechanically and chemically performance.By This it is found that base reservoir temperature to preparing how important high-quality optical filter is！

Utility model content

The utility model is directed to a kind of vacuum coating equipment, proposes both to realize using the method for applying ac high voltage Low temperature plated film, i.e. holding optical filter temperature in whole preparation process is no more than 50 DEG C, but it is excellent to also ensure that optical filter has Optics, mechanically and chemically property, meet real requirement.This is to say, how optical filter to be kept to realize low temperature during the preparation process And how to ensure that optical filter realizes that excellent optics, mechanically and chemically property is the core that the utility model waits exploring and solving Problem.

The purpose of the utility model is to provide a kind of vacuum coating equipments, pass through the thin-film material in vacuum coating equipment vacuum chamber A pair of electrodes is set between evaporation source and optical filter work rest, and applies ac high voltage in high vacuum evaporation film, to obtain Obtain the Thin Film Filter that optics, machinery, chemical property are excellent in low temperature substrates.

The design of the utility model is as follows: to obtain high performance thin film optical filter, the prior art often first adds plated film substrate Heat arrives 100~350 DEG C of temperature (mostly 200~300 DEG C), then uses electron beam evaporation high-temperature oxide in high vacuum conditions Dura mater material, and high-quality thin-film optical filter is prepared using high energy ion beam assisted deposition technology.But it in certain occasions, prepares thin The substrate of film optical filters is not allow heating, such as the substrate of optical plastic, high-precision optical part and photoelectric device composition It is extremely sensitive to temperature, therefore base reservoir temperature must usually be controlled at 70 DEG C even 50 DEG C or less when plated film.So, as first Does is problem, how being just able to maintain optical filter, substrate temperature consistently less than 50 DEG C during the preparation process? solve the problems, such as this, firstly, Naturally, it is necessary to abandon the substrate heating process of the prior art；Secondly as electron beam evaporation source meeting when high-temperature material evaporates A large amount of radiant heat is generated, base reservoir temperature is caused slowly to rise, it is therefore necessary to abandon high-temperature oxide dura mater material, having no alternative can only The selection soft film material that evaporating temperature is lower, radiant heat is less, in soft film material, typical high-index material has vulcanization Object, selenides etc., typical low-index material are mainly fluoride.Finally, ion beam assisted deposition technology must also be abandoned, Because very widely used today Ke Fuman ion source can equally radiate amount of heat, substrate is caused to heat up.If abandoning above three A heating element, then it is entirely possible for realizing that base reservoir temperature is lower than 50 DEG C.Regrettably, three elements are abandoned, reduce substrate temperature After degree, the optical filter of preparation will appear a series of quality problems, and as described in " background technique " above, including film layer is poly- Collect density, optical instability, tie tired tensile stress, substrate deformation, film adhesion, film hardness, film firmness, chemistry surely It is qualitative etc., cause optical filter to be unable to practical application because optics, machinery, chemical property are too poor, so design Second Problem It is the most important thing, i.e., remains to prepare the high-quality optical filtering for meeting practical application when how can just be maintained at substrate temperature less than 50 DEG C Piece? the utility model is final to propose to use zinc sulphide (ZnS) on the basis of analyzing thin evaporated film soft film material and testing As high-index material, ice crystal (Na₃AlF₆) it is used as low-index material.Reason is that first, both soft film materials Evaporating temperature is lower, about 980~1000 DEG C, low higher than 2000 DEG C compared to the evaporating temperature of high-temperature oxide dura mater material perhaps More, the heat radiation of response reduces then more.Second, in all soft film materials, ZnS film refractive index with higher, visible Light district center wavelength 550nm is about 2.35, although the refractive index of zinc selenide film is higher than ZnS-film, its absorption can be than ZnS film High several orders of magnitude, so selecting ZnS film as high-index material and being most suitable, and Na₃AlF₆It is to be rolled in all thin-film materials It is minimum to penetrate rate, it and the cooperation of ZnS film can reach optical performance requirements with least film layer number.Third, it is most important that this two Kind material has a common important feature, that is, can generate ionization when being evaporated in vacuo, this is the core of the utility model, this Kind phenomenon substantially be can not see in other thin-film materials.ZnS film can resolve into Zn and S in evaporation, but solidifying in film During knot, Zn and S can regroup again, so remaining to obtain stoichiometry and ZnS almost the same film layer.This deposition machine Reason be able to explain the phenomenon that condensation coefficient of ZnS film declines rapidly as base reservoir temperature rises well.Similarly, Na₃AlF₆ Film can also resolve into NaF and AlF in evaporation₃, under lower evaporating temperature, with NaF dominance in steam, conversely, AlF₃It is dominant Gesture.Since the refractive index of NaF is slightly below AlF₃Refractive index, this cryolite film for also explaining rapid evaporation well has The reason of high index.It is contemplated that ZnS film and Na₃AlF₆Film evaporation when decomposition must along with ionization, so A pair of electrode for applying ac high voltage can be introduced, material atom or the molecule high speed under high voltage electric field effect of ionization are made Movement, to increase the kinetic energy of deposit particle? it is set up if imagined, effect should be with ion beam assisted deposition technology phase Seemingly, but this ancillary technique in high vacuum conditions will not glow discharge, any heat radiation will not be generated, be entirely cold auxiliary Deposit is helped, not as ion beam assisted deposition can generate a large amount of heat.Reality is tested it has proven convenient that the method can be lower than 50 DEG C of base Easily obtained at a temperature of bottom better optical, machinery, chemical property ZnS/Na₃AlF₆Thin Film Filter, it was demonstrated that imagination establishment, Design is correct.

To achieve the above object, the specific technical solution that the utility model is taken is:

A kind of vacuum coating equipment, comprising: vacuum chamber is arranged in the indoor optical filter work rest of the vacuum (before plated film Sample claims plated film substrate, and the sample after plated film claims optical filter, and optical filter work rest is for setting up plated film substrate, optical filter) and It is arranged in the indoor thin-film material evaporation source of the vacuum；

It is provided between the thin-film material evaporation source and optical filter work rest and at the optical filter work rest A pair of electrodes, described a pair of electrodes are electrically connected with the ac high voltage source being arranged in outside the vacuum chamber.

The utility model in high vacuum conditions thin evaporated film material when, to electrode apply ac high voltage, it is low to realize The purpose of temperature manufacture Thin Film Filter.

Further, the thin-film material evaporation source includes resistance heating evaporation source and electron beam evaporation source.

Further, described a pair of electrodes regards vacuum chamber size with a distance from the optical filter work rest and different, generally For 20~100mm, the utility model is preferably 40mm.

Further, described a pair of electrodes is made of two semicircular rings, and which symmetrically separates 20~ 100mm (end symmetric of i.e. two semicircular rings separates 20~100mm), is preferably 40mm.

Further, the annulus of electrode neglects greatly coating machine diameter or optical filter work rest size and different, and general annulus is straight Diameter is close with work rest diameter, such as 200~1200mm, and the utility model is preferably 400mm, i.e. the half of two semicircular rings Diameter is 100~600mm, and the utility model is preferably 200mm.

Further, two semicircular rings are made of the pure aluminum plate of 0.5~2mm of thickness, and the utility model is preferential For 1.2mm, two semicircular rings are wrapped up by the clean pure aluminum foil of 0.01~0.1mm of thickness (0.05mm), and are being filtered every time It is replaced after mating plate preparation, to be reduced as far as pollution of the coating evaporation material to electrode.

Further, the width of two semicircular rings is 10~40mm, and the utility model is preferably 20mm.

Further, the ac high voltage source provides ac high voltage, and the frequency of the ac high voltage is 50Hz, voltage are 3.2~3.6KV, and the preferential voltage of the utility model is 3.4KV.The ac high voltage source is using high electricity Pressure, low current transformer.Two semicircle ring electrodes are supported by two stainless steel high-field electrodes, with high voltage, low current transformer Be connected, and with coating machine high-voltage isulation.

A kind of low temperature preparation method of Thin Film Filter, using vacuum coating equipment described in the utility model, including it is following Step:

It 1) must be 100~350 DEG C using the material of low temperature preparation, high temperature when plated film substrate is to high temperature sensitive, it is low Temperature is 30 DEG C~70 DEG C, and plated film substrate is mounted on optical filter work rest, selects ice crystal Na₃AlF₆As low-refraction material Material, low-index material are evaporated using resistance heating evaporation source, select zinc sulphide ZnS as high-index material, high refractive index Material is evaporated using electron beam evaporation source；

2) by resistance heating evaporation source and electron beam evaporation source evaporation prepared in plated film substrate low-index film and High refractive index layer, during the preparation process, ac high voltage source provide ac high voltage, the high electricity of the exchange for a pair of electrodes The frequency of pressure is 40Hz~60Hz, voltage is 3.2~3.6KV, completes the preparation of Thin Film Filter.

In step 1), plated film substrate is must be using the material of low temperature preparation to high temperature sensitive, and Thin Film Filter is by plating Film substrate and plural layers composition.Plated film substrate includes optical plastic substrate, some high-precision optical parts and photoelectric device etc..

Under the conditions of low vacuum, ion bombardment technique can be implemented as needed by applying ac high voltage on the electrode, to go Except the grease type pollution of substrate surface.

Electron beam evaporation source is preferentially used for the evaporation of ZnS-film, and to reduce the absorption loss of ZnS-film, and resistance adds Thermal evaporation sources are preferentially used for the evaporation of cryolite film.

In step 2), the frequency of the ac high voltage is 50Hz, voltage is 3.2~3.6KV, the utility model it is excellent First voltage is 3.4KV.

The Thin Film Filter includes antireflective coating, highly reflecting films, beam splitting coating, polarizing coating, depolarized vibrating diaphragm, light cutoff filter Piece and bandpass filter etc..

A kind of low temperature preparation method of Thin Film Filter, it be vacuum coating equipment vacuum chamber thin-film material evaporation source and A pair of electrodes is set between optical filter work rest and at optical filter work rest, in high vacuum conditions thin evaporated film material When, ac high voltage is applied to electrode, to realize the purpose of low temperature manufacture Thin Film Filter.Thin-film material is by high-index material Zinc sulphide (ZnS) and low-index material ice crystal (Na₃AlF₆) composition.The evaporation source of thin evaporated film material is electron beam evaporation Source or resistance heating evaporation source.Wherein substrate be to high temperature sensitive and must use low temperature preparation material, such as optical plastic base Bottom, some high-precision optical parts and photoelectric device etc..The electrode is formed by two in the fine aluminium ring of semicircle, and is distinguished One approximate annulus insulated from each other of composition below work rest is set.

Compared with prior art, the utility model has the beneficial effects that

1. the prior art is frequently with following optical filter preparation process: plated film substrate being heated to temperature 200~300 first DEG C, electron beam evaporation high-temperature oxide dura mater material is then used in high vacuum conditions, while being assisted using high energy ion beam Deposition technology, to obtain optical filter best in quality.But the utility model is the occasion for not allowing to heat for filter substrate, Such as to the substrate of optical plastic, high-precision optical part and photoelectric device composition, base reservoir temperature must be controlled 70 when plated film DEG C so 50 DEG C hereinafter, so, first of all, it is necessary to abandon the substrate heating process of the prior art；Secondly as high-temperature material evaporates When electron beam evaporation source can generate a large amount of radiant heat and base reservoir temperature is caused to rise, therefore it is hard also to abandon high-temperature oxide Membrane material, the selection soft film material that evaporating temperature is lower, radiant heat is less: zinc sulphide and ice crystal；Finally, must also abandon from Beamlet assisted deposition technology causes substrate to heat up because ion source can equally radiate amount of heat.If abandoning above three simultaneously A heating element then can be achieved base reservoir temperature and be lower than 50 DEG C.Low temperature plated film has the advantage that: 1) is due to substrate warm-up time Very long, the cooling down time is longer, greatly prolongs so being coated with process time, therefore low temperature plated film is greatly improved production efficiency. 2) substrate heats, and especially when temperature is more than 250 DEG C, not only vacuum chamber is deflated serious, and What is more, as substrate rotation etc. Movement mechanism is easy to stuck.3) low temperature plated film will not induce substrate deformation, will not generate thermal stress.4) coagulating due to ZnS film Clone number is extremely sensitive to temperature, at 150 DEG C of base reservoir temperature, condensation coefficient decline 50%, so low temperature plated film can ensure that ZnS Film normally condenses into film.5) most importantly low temperature plated film can ensure that substrate safely, the damage that avoids high temperature to substrate.

2. current conventional fabrication process may insure the quality index of optical filter, but to the utility model low temperature plated film system Standby optical filter but will appear many quality problems, including film layer gather density, optical instability, knot tired tensile stress, substrate Deformation, film adhesion, film hardness, film firmness, chemical stability etc., cause optical filter because of optics, machinery, chemistry Penalty and be unable to practical application.The utility model proposes be used as high-index material, ice crystal using zinc sulphide (ZnS) (Na₃AlF₆) be used as low-index material, both materials have a common important feature: can be generated when vacuum evaporation from Sonization, it is possible to introduce a pair of electrode for applying ac high-voltage, make the material atom of ionization or molecule in high voltage electric field With lower high-speed motion, to increase the kinetic energy of deposit particle, effect is especially such as ion beam assisted deposition technology.This electric field-assisted In high vacuum conditions will not glow discharge, any radiant heat will not be generated, be entirely a kind of cold assisted deposition technology, it Can lower than obtained under 50 DEG C of base reservoir temperature better optical, machinery, chemical property ZnS/Na₃AlF₆Thin Film Filter.

Detailed description of the invention

Fig. 1 is that the vacuum vaporation system configuration of vacuum coating equipment and the configuration of the ac high-voltage electrode of the utility model are shown It is intended to；

Fig. 2 is the schematic diagram of the electrode pair of the fine aluminium ring composition of two semicircles in the utility model；

Fig. 3 is the ZnS/Na with Conventional cryogenic plating film preparation₃AlF₆Thin Film Filter is when just terminating preparation and after the moisture absorption Test curve figure of the transmissivity (T) to wavelength (λ), in which: when a) just terminating preparation, b) after the moisture absorption；

Fig. 4 be the utility model apply ac high voltage after with low temperature plating film preparation ZnS/Na₃AlF₆Thin Film Filter exists Transmissivity (T) when just terminating preparation and after the moisture absorption is to the test curve figure of wavelength (λ), in which: when a) just terminating preparation, b) and it inhales After tide.

Specific embodiment

Fig. 1 is that the vacuum vaporation system of vacuum coating equipment configures and what the ac high-voltage electrode of the utility model configured shows It is intended to.In Fig. 1, vacuum coating equipment vacuum chamber 1 obtains high vacuum by the exhaust of bleeding point 2.In vacuum chamber 1, it is equipped with plated film Substrate heating system 3, substrate to be heated to before plated film the temperature of setting.Lower section against heating system 3 is plated film base Bottom or optical filter work rest 4 (sample before plated film claims substrate, and the sample after plated film claims optical filter), work rest 4 are a carryings The disk of plated film substrate or optical filter, in plated film, work rest 4 is uniformly atwirl.One is placed in disc centre position Block film thickness monitoring piece 6, disk perimeter are arranged various plated film substrates 5,5 ', and plated film substrate 5,5 ' is coated with the optical filtering of design Optical filter is frequently referred to after piece membrane system.Thin-film material evaporation source is made of resistance heating evaporation source 9 and electron beam evaporation source 10, and two kinds Evaporation source has their own characteristics, and can be selected according to evaporation material property.Respectively there is a control evaporation material to steam above evaporation source The plate washer 11,11 ' of vapour, accurately to control the thickness of each tunic of optical filter.Film thickness monitoring system is by light source 13, control optical filter 14, monitoring piece 6 and photelectric receiver 15 etc. form.Ion source 12 is used for ion beam assisted deposition, to obtain the thin of function admirable Film optical filters.Thin-film material is high-index material zinc sulphide (ZnS) and low-index material ice crystal (Na₃AlF₆), and respectively It is evaporated by electron beam evaporation source 10 and resistance heating evaporation source 9.

It is arranged between thin-film material evaporation source 9,10 and optical filter work rest 4 and at optical filter work rest 4 a pair of Electrode 7,7 ', the semicircular ring made of two pure aluminum plates of electrode 7,7 ' are constituted, it regards vacuum chamber at a distance from optical filter work rest 4 Size and different, generally 20~100mm, the utility model are preferably 40mm.The width of two semicircle ring electrodes is 10~40mm, The utility model is preferably 20mm.In high vacuum conditions when thin evaporated film material, above apply frequency 50Hz, electricity in electrode 7,7 ' The ac high voltage of 3.2~3.6KV is pressed, the preferential voltage of the utility model is 3.4KV.Two fine aluminium semicircle ring electrodes 7,7 ' are not by Become rusty steel high pressure introduce electrode 8,8 ' support, be connected with high voltage, low current transformer 16, and with coating machine high-voltage isulation.

Fig. 2 is the schematic diagram of the electrode pair of the fine aluminium ring composition of two semicircles of the utility model.Electrode 7,7 ' is two and half Round fine aluminium ring, and it is separately positioned on one approximate annulus insulated from each other of composition below work rest 4, as shown in Fig. 2, two The separation of semicircular ring is about 40mm.Annulus neglects 4 size of optical filter work rest and different, general circle diameter and work rest greatly Diameter is approximately uniform, such as 200~1200mm, and the utility model is preferably 400mm.Electrode 7,7 ' by 0.5~2mm of thickness fine aluminium Plate is directly cut, and the utility model is preferentially with a thickness of 1.2mm.The making step of electrode are as follows: 1. are equal to by semicircle perimeter π R 628mm, width 20mm are cut into two plate electrode plates from the pure aluminum plate of thickness 1.2mm；2. above-mentioned two plate electrodes plate presses R= 200mm curves two semicircular rings, and is combined into circle；3. to prevent two semicircular rings from contacting with each other, therefore being clipped in contact site 20mm, ultimately forms the appearance of Fig. 2, i.e., the separation of two semicircular rings is about 40mm.

Embodiment one

Fig. 3 is the ZnS/Na with Conventional cryogenic plating film preparation₃AlF₆Thin Film Filter is when just terminating preparation and after the moisture absorption Test curve figure of the transmissivity (T) to wavelength (λ), in which: a) indicate the transmissivity versus wavelength tested when optical filter just terminates preparation Curve, b) it is the transmissivity versus wavelength curve tested after allowing its abundant moisture absorption after prepared by optical filter.The Conventional cryogenic plated film of Fig. 3 is Refer to be evaporated in vacuo when being coated with optical filter and take mentioned-above " three are abandoned " technique: abandoning substrate heating, abandons electron beam steaming High-temperature oxide dura mater material is sent out, ion beam assisted deposition technology is abandoned, to ensure that base reservoir temperature is no more than 50 DEG C, but is not drawn Enter ac high voltage assisted deposition technology.Test the film structure of optical filter are as follows: S | (HL)²H4LH(LH)²| A, wherein S is indicated Substrate, H are high refractive index zinc sulphide (ZnS) film of quarter-wave optical thickness (QWOT), and L is quarter-wave optics Low-refraction ice crystal (the Na of thickness (QWOT)₃AlF₆) film, 4L is wall.It may be noted that this is that a kind of structure is simplest Single-chamber optical filter because its space layer has two half-wavelength thickness, therefore is also known as double half-wave single-chamber optical filters.This optical filter Though characteristic be not very well, the number of plies is few, is simple to manufacture, and influencing characterisitic variation factor it is simple and direct, easy analysis, thus select This film structure is selected, intuitively to analyze the effect of ac high voltage assisted deposition.

In high vacuum evaporation, high-index material zinc sulphide (ZnS) is evaporated using electron beam evaporation source 10, because of ZnS It is lump shaped crystalline material, when evaporation is distillation again, so electron beam evaporation is convenient to implement to evaporate on the surface of the material, if with Resistance heating evaporation, material are easy to overheat.And low-index material ice crystal (Na₃AlF₆) resistance heating evaporation source 9 is selected to evaporate It is most suitable.In evaporation process, the thickness of each tunic is by film thickness monitoring system implementing monitoring.Fig. 3 a) it is just to terminate to prepare When optical filter transmissivity versus wavelength test curve, this curve can consider that optical filter also has little time the moisture absorption, and characteristic and design are special Property is very close.By Fig. 3 a) it is found that the centre of homology wavelength of optical filter is 560nm, maximum transmission rate is 91% (because substrate is carried on the back There is about 4% reflection loss on surface, therefore the transmissivity of practical optical filter is about 95%) half width 8nm, short wavelength cutoff area Minimum transmissivity is 1.04% (in wavelength 506nm), and the minimum transmissivity of long-wavelength cut-off is 1.32% (in wavelength 621nm). Fig. 3 b) be Fig. 3 a) just terminate preparation optical filter be put into relative humidity 100% after completing transmissivity versus wavelength curve test Sealing container in the transmissivity versus wavelength curve tested after the moisture absorption by 56 hours.After the moisture absorption it can be seen from Fig. 3 b) The transmissivity versus wavelength curve of optical filter produces very big variation, and the centre of homology wavelength of optical filter is moved on to from 560nm to long wave 607nm, long move reach 47nm fully；Maximum transmission rate drops to 48% from 91%, and half width is broadened from 8nm to 30nm, shortwave The minimum transmissivity of cut-off region rises to 5.04% (in wavelength 540nm) (in wavelength 506nm) from 1.04%, long-wavelength cut-off Minimum transmissivity rises to 4.96% (in wavelength 697nm) (in wavelength 621nm) from 1.32%.Comparison diagram 3a) and Fig. 3 b) can be with Be apparent from, with Conventional cryogenic plating film preparation optical filter optical stability be it is very poor, after the optical filter moisture absorption performance generate it is bright It is aobvious to deteriorate, it is mainly manifested in two aspects: first is that characteristic curve drifts about to long wave；Second is that maximum transmission rate decline, half width increase Greatly, the cut-off degree of short wavelength cutoff area and long-wavelength cut-off reduces.

With the optical filter of Conventional cryogenic plating film preparation, why optical stability is very poor, and main cause is because of vapor molecule Or kinetic energy when atomic deposition is too low, ZnS and Na₃AlF₆Evaporating temperature be about 1000 DEG C, according to formula E=3kT/2, in formula, E is kinetic energy of the evaporation particle in condensation, and k is Bo Ziman constant (=8.62x10^-5EV/ ° of K), T is thin-film material evaporating temperature (Kelvin), to ZnS and Na₃AlF₆For 1273 ° of K, can then calculate kinetic energy E is only 0.16eV.Due to evaporation particle kinetic energy Too low, when deposit, cannot migrate again in substrate surface, cause film layer structure loose, gather density is very low, does not only result in light finally It is very poor to learn stability, and causes to tie tired tensile stress, film adhesion, film hardness, film firmness, chemical stability etc. one Series of problems, in short: causing optical filter optics, machinery, chemical property too poor and be unable to practical application.

Embodiment two

Fig. 4 be the utility model apply ac high voltage after with low temperature plating film preparation ZnS/Na₃AlF₆Thin Film Filter exists Transmissivity (T) is to the test curve figure of wavelength (λ) when just terminating preparation and after the moisture absorption, in which: a) indicates that optical filter just terminates to make The transmissivity versus wavelength curve tested when standby, b) it is the transmissivity versus wavelength song tested after allowing its abundant moisture absorption after prepared by optical filter Line.The optical filter of transmissivity versus wavelength curve shown in corresponding diagram 4, preparation process and film structure with it is shown in Fig. 3, Unique difference is exactly: optical filter shown in Fig. 4 introduces ac high voltage assisted deposition technology in the preparation.Ac high voltage Frequency be 50Hz, voltage 3.4KV.The upper limb of electrode 7,7 ' is 40mm with a distance from optical filter work rest 4.Electrode 7,7 ' by Two semicircular rings are made in the pure aluminum plate of thickness 1.2mm, and the separation of two semicircular rings is about 40mm.The width of two semicircle ring electrodes Degree is 20mm, and circle diameter is close with work rest diameter, and the utility model is preferably 400mm.Two semicircle ring electrodes 7,7 ' It is supported by introducing electrode 8,8 ' with the stainless steel high pressure of coating machine high-voltage isulation.Before each optical filter is coated with, electrode 7,7 ' and It introduces electrode 8,8 ' to be wrapped up by the clean pure aluminum foil of thickness about 0.05mm, to be avoided as much as the optical filtering of coating materials dust pollution Piece.In addition, if needing, it can above apply ac high voltage under the conditions of low vacuum at electrode 7,7 ' and implement ion bombardment technique, To remove the grease type pollution of substrate surface.

Fig. 4 a) be optical filter when just having terminated preparation transmissivity versus wavelength test curve, this curve equally can consider optical filtering There are no the moisture absorptions for piece, and characteristic is very close with design characteristics, and here it is the transmissivity versus wavelength test curves of Fig. 4 a) and Fig. 3 a) Very close reason.If two curves have small difference, that be because preparation process and film thickness monitoring error etc. because Caused by element.By Fig. 4 a) it is found that the centre of homology wavelength of optical filter is 559nm, maximum transmission rate is 91% (same, practical filter 95%) transmissivity of mating plate is answered, half width 8nm, and the minimum transmissivity in short wavelength cutoff area is 0.84% (in wavelength 507nm), The minimum transmissivity of long-wavelength cut-off is 1.11% (in wavelength 621nm).Fig. 4 b) be Fig. 4 a) just terminate preparation optical filter exist It is put into after completion transmissivity versus wavelength curve test in the sealing container of relative humidity 100% and was tested after the moisture absorption by 72 hours Obtained transmissivity versus wavelength curve.The centre of homology wavelength of optical filter is basically unchanged after the moisture absorption it can be seen from Fig. 4 b), from 559nm changes to 560nm, and only length has moved 1nm；Maximum transmission rate drops to 84% from 91%, and half width is still 8nm, and shortwave is cut Only the minimum transmissivity in area rises to 1.09% (in wavelength 510nm) (in wavelength 507nm) from 0.84%, and long-wavelength cut-off is most Low transmission rate drops to 0.98% (in wavelength 624nm) (in wavelength 621nm) for 1.11%.Comparison diagram 4a) and Fig. 4 b) can be clear Chu finds out that, due to introducing ac high voltage assisted deposition technology, the optical filter optical stability prepared at low temperature is shown It writes and improves.Though optical filter performance after the moisture absorption has slight change, border using effect in fact is not interfered.This major progress, makes The low temperature plated film of the utility model has practical application value, directly provides for the low temperature preparation of optical filter a kind of simple and real Method.

Its mechanism is studied carefully, this is because ZnS and Na₃AlF₆In evaporation along with ionization, the material atom of ionization or point Son generates high-speed motion under the action of ac high voltage, and the kinetic energy for then depositing particle no longer follows formula E=3kT/2.By It is greatly increased in the kinetic energy of deposit particle, effect is just similar to ion beam assisted deposition technology, makes ZnS and Na₃AlF₆Film Gather density significantly improves, finally, even if in temperature lower than remaining to obtain better optical, machinery, chemically in 50 DEG C of substrate The Thin Film Filter of energy, meets actual operation requirements.

Claims (8)

1. a kind of vacuum coating equipment, comprising: vacuum chamber, setting in the indoor optical filter work rest of the vacuum and are arranged in institute State the indoor thin-film material evaporation source of vacuum；It is characterized in that, between the thin-film material evaporation source and optical filter work rest And a pair of electrodes, described a pair of electrodes and the friendship being arranged in outside the vacuum chamber are provided at the optical filter work rest Flow high voltage source electrical connection.

2. vacuum coating equipment according to claim 1, which is characterized in that the thin-film material evaporation source includes that resistance adds Thermal evaporation sources and electron beam evaporation source.

3. vacuum coating equipment according to claim 1, which is characterized in that described a pair of electrodes is from the optical filter workpiece The distance of frame is 20~100mm.

4. vacuum coating equipment according to claim 1, which is characterized in that described a pair of electrodes is by two semicircular ring groups At two semicircular rings symmetrically separate 20~100mm.

5. vacuum coating equipment according to claim 4, which is characterized in that the radius of two semicircular rings is 100 ~600mm.

6. vacuum coating equipment according to claim 4, which is characterized in that two semicircular rings by thickness 0.5~ The pure aluminum plate of 2mm is made, and two semicircular rings are wrapped up by pure aluminum foil.

7. vacuum coating equipment according to claim 6, which is characterized in that the pure aluminum foil with a thickness of 0.01~ 0.1mm。

8. vacuum coating equipment according to claim 4, which is characterized in that the width of two semicircular rings is 10~ 40mm。