CN101161856A - Optical coating film thickness monitoring automatic control system and monitoring method - Google Patents

Abstract

The invention relates to an automatic control system for monitoring the film thickness of optical filming. A light projecting device is directly connected with a light entrance port of a film coating machine or is connected with an optical splitter and a reflector chest for projecting light generated by the light projecting device into the film coating machine, a light exit portal of the film coating machine is connected with a light transporting element which is connected with a light entrance port of the optical splitter, a light exit portal of the optical splitter is further connected with a light entrance port of a photoelectric signal changeover gear, or an exit ray of the film coating machine reflects light into the photoelectric signal changeover gear through the reflector chest, an electrical signal output end of the photoelectric signal changeover gear is connected with a computer through a signal processing unit. The invention further relates to an automatic control method for monitoring the film thickness. The invention improves the stability and accuracy of monitoring the film thickness and meets the requirement of filming with high degree of accuracy.

Description

Optical coating film thickness monitoring automatic control system and monitoring method

Technical field

The invention belongs to optical coating and monitor the field in real time, particularly relate to a kind of utilizing the monitor control system and the autocontrol method of optical coating evaporation workpiece surface thickness.

Background technology

Existing film thickness gauge is normally analog, does not have the Computer Processing function, and stability and accuracy are very poor, are not suitable for the continuous multilayer plated film.Can not satisfy the requirement of high precision plated film.Existing in addition film thickness gauge optical axis debugging is very complicated, spend a large amount of time of user or commissioning staff.In addition, existing film thickness gauge also has following defective: what 1, light emitted part adopted usually is halogen tungsten bulb, or side one plane or cambered surface speculum are so that strengthen the brightness of emission light behind halogen tungsten bulb.Because the light that halogen tungsten lamp itself sends is more weak, and light source is the directional light that scattered light or process reflection produce at the light of exit pupil direction emission, the light beam that sees through of exit pupil is very little in addition, overwhelming majority ray cast wastes to the light source tank wall, therefore the utilization ratio of luminous energy is low, and the light of outgoing too a little less than, cause thus a little less than the optical signal of supervisory system, monitoring identification difficulty is big, weak effect.

2, illuminator directly is connected with power supply, and the fluctuation of voltage of supply causes the brightness instability of light source, thereby has influence on the accuracy of optical monitoring signal, causes the film thickness monitoring weak effect.

3, the cooling measure effect is bad in the light-source box, and the bulb long time continuous working causes the light-source box temperature too high, and the power supply impedance is increased, and influences the bulb illumination effect.

4, the halogen tungsten bulb of Cai Yonging significantly reduces at later stage in work-ing life luminescent properties, to directly have influence on the signal quality of supervisory system, therefore must in time change, but by the manual operation memory, can not grasp the control replacing time timely and accurately, its poor reliability.

5, the modulator that is used for modulated light wave adopts the rotary power of operational amplifier 1 synchronous machine as chopper wheel usually, speed stability is relatively poor, cause the wavelength and the frequency of modulated beam of light inhomogeneous thus, influence and reduced the monitoring accuracy and the monitoring effect of optical signal.Secondly, the unthreaded hole on the chopper wheel mostly is circle or sector structure, makes the light wave after the modulation be approximate choppy sea curve, and its peak value produces higher harmonic later on through filtering process, makes signal produce fluctuation, brings difficulty for the monitoring of signal.

6, the condensing lens in the optically focused mirrored cabinet, its spot position is fixing and nonadjustable, when transmitted light along with the variation of different coating equipments or installation site the time, owing to can't adjust the focal length and the multiplying power of lens, and make the hot spot that projects on the comparison sheet inhomogeneous, can not all project on the comparison sheet, cause optical energy loss thus, and cause the decay of optical signal.

7, when emitted light beams enters reflector box, because of due to the structure, make light beam catadioptric path many in the mirrored cabinet, optical length causes optics many, complex structure, manufacturing cost height.Secondly,, can not adapt to the optical signal projection of various different distance because outgoing, the reflection angle of optical axis are difficult to adjust, thus little to the scope of application of plated film type, and the installation site also is very limited.Simultaneously, it is big in use to adjust difficulty, not only wastes time and energy, and efficient is low, and is difficult to quick and precisely will launch reliably optical signal and projects plated film relatively on the sheet.

8, in optical membrane plating monitoring system, the power of optical signal, the efficient of opto-electronic conversion plays important effect for the sensitivity and the accuracy of supervisory system.And the light that is used for photoelectric conversion device in the existing technology accepts that senser element usually adopts is photomultiplier, and this component size is big, it is many to take up room, and uses this element must supporting high-voltage power supply, causes the circuit complexity, the cost of manufacture height.Secondly, the condenser lens that transmitter is accepted in the light path mostly is fixed installation, make the stand-off distance of lens focus point to regulate, be difficult to the optical signal focus point is thrown into accepting on the face of transmitter accurately, cause the photosignal efficiency of conversion low, be easy to generate signal attenuation, influence the monitoring effect of whole monitoring system thus.

Summary of the invention

The purpose of this invention is to provide a kind of optical coating film thickness monitoring automatic control system, improve the stability and the accuracy of film thickness measuring, satisfy the requirement of high precision plated film with computer monitoring function.

The present invention also aims to provide a kind of optical coating film thickness monitoring method.

For achieving the above object, the present invention adopts following technical scheme: a kind of optical coating film thickness monitoring automatic control system, it comprises light projector device, optical splitter, the photosignal transfer equipment, signal processing unit and computer, light projector device directly be connected with the light entrance port of coating equipment or and optical splitter, reflector box connects and is used for the light that light projector device sends is throwed into coating equipment, the optical emission exit of coating equipment connects an optical communication means and is connected with the light entrance port of optical splitter, the optical emission exit of optical splitter is connected with the light entrance port of photosignal transfer equipment again, perhaps the emergent ray of coating equipment reflects light into the photosignal transfer equipment by reflector box, and the electrical signal of photosignal transfer equipment is connected with computer by signal processing unit.

Described film thickness monitoring automatic control system adopts reflected light path on the up-set type, light projector device, optical splitter, reflector box, photosignal transfer equipment are formed incident/reflected light path, after assembling successively, each parts is contained in the top in coating equipment evaporation chamber, it is incident optical signal to be projected plated film compare on the sheet, and forms the light emission path of emission optical signal thus; The optical signal that will be projected on the plated film comparison sheet by light reflection mirror reflexes on the photosignal transfer equipment that is connected with this mirrored cabinet again, forms a luminous reflectance path with reflected light signal output.

Described film thickness monitoring automatic control system also can adopt reflected light path under the underneath type, light projector device is installed in the bottom in coating equipment evaporation chamber and forms input path, it is incoming beam to be projected plated film compare on the sheet, and forms the light emission path of emission optical signal thus; Optical splitter and connected photosignal transfer equipment are contained in the bottom of coating equipment evaporation casing, and optical splitter is connected with coating equipment evaporation casing optical emission exit by optical cable and fiber cable joint, forms the luminous reflectance path thus.

Described film thickness monitoring automatic control system also can adopt the transmission-type light path, its light entrance port and optical emission exit are in the corresponding setting of coating equipment evaporation casing upper and lower ends, light projector device is installed in the bottom or the top of coating equipment evaporation casing and forms input path, it projects plated film by the light entrance port with incoming beam compares on the sheet, and forms the light emission path of emission optical signal thus; Optical splitter adopts optical cable and is installed in coating equipment evaporation casing top or the bottom corresponding with launching light path by fiber cable joint, and be connected with the photosignal transfer equipment, be used to accept to project the relatively light transmission signal on the sheet of plated film, form one and will launch the transmission path that optical signal is exported.

Described light projector device is by the light emitted case, modulator, the optically focused lens barrel is formed, in the light emitted case, be provided with the tungstohalogen lamp of band optically focused lampshade, casing one side connects the modulator of a band constant-seed motor by pillar, the output light source end correspondence of modulator is connected with the optically focused lens barrel, be provided with the module of optical system that can move axially adjusting in the lens barrel, the light beam output terminal of optically focused lens barrel is equipped with positioning link by ring flange, described tungstohalogen lamp is by halogen tungsten lamp, the optically focused lampshade and the lamp socket that have ellipsoid are formed, the caustic surface of optically focused lampshade is towards the optical channel of lamp socket, and link to each other with the lamp socket spiral-lock, the center of lamp socket is the cavity with optical channel, and communicate with the light source perforation hole that is provided with on the casing antetheca, lamp socket is an inclined-plane towards the end face of light source, halogen tungsten lamp and lampshade are tilting to be installed on this inclined-plane, the optically focused optical axis of described optically focused lampshade is 10～30 ° (different and different according to ellipsoid curvature) with angle α between the emergent light axis of light beam perforation hole, described modulator is by the modulator housing, chopper wheel and constant-seed motor are formed, chopper wheel is contained in the housing, constant-seed motor is contained in outside the housing, its output shaft is connected with the chopper wheel center, the circumference uniform distribution rectangle unthreaded hole of chopper wheel, described focus lens assembly is by condensing lens, the lens permanent seat, set screw is formed, the barrel of described optically focused lens barrel is provided with and is used to regulate the axially movable adjustment hole of focus lens assembly, condensing lens is packed on the lens permanent seat, and the set screw of installing on it is stretched out outside the adjustment hole.

Described reflector box has a casing that has incident light through hole and emergent light through hole, corresponding position with incident light through hole and emergent light through hole in the casing is provided with a pair of optical surface incident/speculum, what be connected with this incident/speculum is that the lower surface is the microscope base on an inclined-plane, the top of microscope base is provided with stretches out the outer adjusting part that is used to adjust incident/mirror angle and upper-lower position of mirrored cabinet, described adjusting part comprises the tension spring regulating part of the upper-lower position regulated that is contained on the box body wall and is used for the jackscrew regulating part of adjusting angle that jackscrew regulating part and microscope base upper end touch.

Described photosignal transfer equipment is made of optics mirrored cabinet and conversion of signals case two portions, combining site between the two connects by fastening piece, wherein, the optics mirrored cabinet is positioned at the light beam exit end of thickness optical signal transmission parts, be provided with the focus lens assembly that can move axially adjusting in it, be provided with photosignal change-over circuit plate in the conversion of signals case by seat supports, casing is provided with terminal stud, the center of bearing has the photo-signal channel hole that is communicated with the optics mirrored cabinet, described focus lens assembly is the condenser lens of assembling by successively, the lens permanent seat, set screw is formed, and is arranged with on the tank wall of described optics mirrored cabinet to be used to regulate the axially movable elongated groove opening of focus lens assembly.

Described photosignal change-over circuit comprises: a light is accepted senser element, is used to accept optical signal and is converted to electrical signal; The I/V translation circuit of a big multiplying power is used for photo-signal is transformed to voltage signal; A prime amplifier is used for the voltage signal of I/V translation circuit output is tentatively amplified.

Described signal processing unit is connected to form successively by programmable amplifier, wave filter, alternating current amplifier, absolute value rectifying circuit, direct-current amplifier, A/D transition card, the input terminus of programmable amplifier is connected with the output terminal of photosignal transfer equipment, the direct current amplifying signal is connected on the A/D transition card, the A/D transition card is connected with computer, described programmable amplifier also is connected with micro-chip, is used to accept the gain control signal that micro-chip sends.

The present invention also provides a kind of optical coating film thickness monitoring method, and it may further comprise the steps:

(1), after the vacuum system of coating equipment is ready to complete, can begin plated film in, send signal by film thickness gauge, carry out the evaporation operation;

(2), before the beginning evaporation, computer is according to processing requirement, send the wavelength monitor order by serial port to single-chip computer control system, SCM system begins later on to send turn signal to the stepper-motor of optical splitter receiving order, the control step motor rotates to specified supervisory wavelength, and the supervisory wavelength value is set;

(3), the voltage change signal that amplifies by computer A/D capture card acquired signal processing unit of computer and be converted to reflectivity, according to difference when the anterior layer Coating Materials, different amplifier gains is set, SCM system is after detecting this order, send order to micro-chip, micro-chip interpreted command and control figure potentiometer, the resistance of regulating digital regulation resistance, circuit is converted to change in gain according to change in resistance;

(4), computer sends the order of conversion crucible to the crucible controller, crucible rotating is to the given process position, and two overlap crucibles about control, and every cover crucible is made up of several crucibles, each crucible is placed different coating materials, and computer sends binary-coded decimal by the IO port and carries out the crucible switching;

(5), computer is by IO port output pulse signal, control coating equipment electron beam gun is opened, open line by another one IO port, beginning fritting operation, five sections pre-process of smelting in film thickness gauge, setting according to the user, computer is changed the line value of exporting electron beam gun by D/A, the automatically pre-process of smelting that begins to be scheduled to;

(6), after fritting is finished, give brilliant control with the electron beam gun control and carry out line control, the announcing circuit transfer relay switches to brilliant control with control signal, brilliant control will be carried out vaporator rate control according to the rate-controlling order that film thickness gauge sends by serial ports;

(7), send beginning plated film signal, COMPUTER DETECTION is when opening the signal of baffle plate, and beginning is according to the variation of A/D capture card detection light value, and real-time curve is presented on the screen at film thickness gauge;

(8), computer calculates according to the variation of light value, when calculating evaporation when proceeding to peak point, calculate real-time specific refractory power automatically, and revise the arrests light value automatically, and revised theory curve automatically;

(9), evaporation proceeds, according to the evaporation process that sets in advance, when the A/D capture card received precalculated arrests voltage, computer sent and closes the baffle plate order, and notice sends the brilliant control of order control by serial ports, stopped the evaporation of this layer;

(10), according to the requirement of technology evaporation state, judge whether to begin automatically to descend the evaporation of one deck, if begin automatically, continue to send the evaporation order and begin to be coated with down one deck, the operation of repeating step 2～10 stops up to all technologies.

The present invention utilizes computer to carry out film thickness monitoring, has improved the stability and the accuracy of film thickness monitoring, has satisfied the requirement of high precision plated film.By with the cooperating of crystalline substance control, perfectly detect the variation of light value, and according to the difference of Coating Materials, gain is set automatically, reach maximum precision, and can control brilliant control accurate vaporator rate is set, and difference according to coating process, different APC (pressure two-position controller) is set, can be in coating process according to the variation of technology, when reaching peak point, calculate the real-time change of refractive of this layer plated film in real time, according to the voltage of real-time change of refractive correction arrests, reach high-precision requirement then.

Light path of the present invention can simple adjustment, common installation personnel only needs several minutes just can finish the optical axis debugging, and can in various coating equipment, can use, and can guarantee the spot size unanimity on the comparison sheet, it is very low for the requirement of comparing chip system, can adapt to the comparison sheet Controlling System of different sizes and quantity.Optical system has been passed through versatility calculating, only needs to change the lens of different focal and the requirement for optical system that lens barrel just can be finished the coating equipment of different size.In configuration aspects, light path system can use reflection, reflection or transmission down.And according to the restriction of the installation dimension of coating equipment, can use unified mirrored cabinet, when the installation site is crowded, can very easily finish installation.When using band to spare light light projector fiber optic conduction automatically, installation method is very easy to, and can guarantees that the angle that transmits and receives is enough little, guarantee measuring accuracy.

Another typical improvement of configuration aspects is to have adopted the tilted-putted method of high brightness Lamp cup, can eliminate the dark problem of center light of halogen tungsten lamp filament, adopts the reflected light of lamp wall part relatively uniformly, can enlarge markedly brightness.

The device of high-gain low-noise has been used in circuit of the present invention aspect, is all carrying out specialized designs aspect the processing of the layout of circuit and noise.The photosignal transfer equipment has adopted cylinder mode, install and debug and all be very easy to, and determine that easily the center is subjected to luminous point, adopt photosignal transfer equipment prime to amplify and the isolating method of post-amplifier, can reach better signal stabilization and precision.The present invention has adopted the high-performance narrow band filter, can effectively eliminate electron beam gun high strength light and from the noise signal of environment.Photomodulator of the present invention can be avoided the interference of the circuit noise of 50HZ and 60hz effectively, makes common-mode noise obtain inhibition, and the stability of signal significantly improves.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the invention 1;

Fig. 2 is the structural representation of the embodiment of the invention 2;

Fig. 3 is the structural representation of the embodiment of the invention 3;

Fig. 4 is the structural representation of light projector device;

Fig. 5 is the circuit of light sources synoptic diagram;

Fig. 6 is the optical splitter formation synoptic diagram;

Fig. 7 is the optical splitter circuit diagram;

Fig. 8 is the reflector box structural representation;

Fig. 9 is the vertical view of Fig. 8;

Figure 10 is a photosignal conversion device structure synoptic diagram;

Figure 11 is the photosignal change-over circuit block diagram among Figure 10;

Figure 12 is the circuit block diagram of signal processing unit;

Figure 13 is the circuit block diagram of programmable amplifier;

Figure 14 is the schematic circuit diagram of second order filter.

Embodiment

Referring to Fig. 1, each label is respectively among the figure: light emitted case 1, modulator 2, optically focused lens barrel 3, optical splitter 4, reflector box 5, photosignal transfer equipment 6, connection support 7, comparison sheet inversion mechanism 8, scratch diskette rotating mechanism 9, evaporation chamber 10, turntable mounting 11, comparison sheet 12, optics substrate 13, workpiece rotating disk 14, signal processing unit 15, computer 16.

Shown in Figure 1 is the general assembly structural representation of the embodiment of the invention 1, what its film thickness monitoring device adopted is reflected light path on the up-set type, comprise light emitted case 1, modulator 2, optically focused lens barrel 3, optical splitter 4, reflector box 5 and photosignal transfer equipment 6, be installed in the top in coating equipment evaporation chamber after each parts is assembled successively.In the evaporation monitor procedure, pass through the modulation spread spectrum of modulator 2 by the light beam of light emitted case 1 ejaculation, by the collimation (referring to Fig. 4) of condenser lens 304 in the focusing barrel 3, project on the incident light speculum 508 in the reflector box 5 (referring to Fig. 8), and project thus on the comparison sheet 12 again.By the relatively reflection (referring to Fig. 8) of the emergent light speculum 505 of thickness optical signal in reflector box 5 of sheet 12 reflections, after optical splitter 4 is handled, conduction enters photosignal transfer equipment 6 and carries out the opto-electronic conversion processing, electrical signal after will changing again can offer computer and handle, monitors after Circuits System is handled.Comparison sheet inversion mechanism 8 among the figure and scratch diskette rotating mechanism 9 belong to the coating equipment matching component, are known technology, and its structure repeats no more.

Referring to Fig. 2, it is the general assembly structural representation of embodiments of the invention 2, monitoring device adopts reflected light path under the underneath type, form input path by light emitted case 1, modulator 2 and optically focused lens barrel 3, after assembling successively, each parts is installed in the bottom in coating equipment evaporation chamber 10, it is incoming beam to be projected plated film compare on the sheet 12, and forms the light emission path of emission optical signal thus; The optical signal output in luminous reflectance path is made up of optical splitter 4 and connected photosignal transfer equipment 6, and optical splitter 4 is installed in the bottom in coating equipment evaporation chamber 12 by optical cable 17 and fiber cable joint 18.Adopting the underneath type light path, is that the light beam through optically focused lens barrel 3 collimations is directly projected on the comparison sheet 12, is directly thrown on the optical splitter 4 by the optical signal of relatively sheet 12 thickness reflection, in the middle of it reflector box need not be set, and structure is simpler, has also shortened the conduction light path.

Referring to Fig. 3, it is the general assembly structural representation of embodiments of the invention 3, monitoring device adopts the transmission-type light path, form input path by light emitted case 1, modulator 2, optically focused lens barrel 3, after assembling successively, each parts is installed in the bottom or the top in coating equipment evaporation chamber 10, it is incoming beam to be projected plated film compare on the sheet 12, and forms the light emission path of emission optical signal thus; The optical signal output of transmission path is made up of optical splitter 4 and connected photosignal transfer equipment 6, optical splitter 4 adopts optical cable 17 and is installed in coating equipment evaporation chamber 10 tops or the bottom corresponding with launching light path by fiber cable joint 18, be used to accept to project the relatively luminous reflectance signal on the sheet 12 of plated film, form one and will launch the transmission path that optical signal is exported.Adopt transmission mode to gather the thickness optical signal, the conduction light path is shortened greatly, also can reduce of the interference of the high light of environment veiling glare in the evaporation chamber and electron beam gun the thickness optical signal.

Referring to Fig. 4, Fig. 5, the antetheca of light emitted case 101 is provided with the light source perforation hole 109 that is used to launch light beam, inside is provided with illuminator 102, this illuminator 102 adopts the halogen tungsten lamp that can produce the intense light source high brightness, the optically focused lampshade that has ellipsoid on the halogen tungsten lamp, lamp socket 107 is packed on the preceding inwall of light emitted box body 101, the centre of lamp socket 107 is the cavity structure that has optical channel 110, its end face towards light source is an inclined-plane, halogen tungsten lamp and lampshade are tilting to be installed on this inclined-plane, make the angle that has 10～30 ° between the emergent light axis of the optical axis of lampshade optically focused and light beam perforation hole, can avoid like this causing outgoing beam to carry blackening because of filament imaging on emergent light axis.Halogen tungsten lamp is positioned on the back focus of ellipsoidal spotlight cover, and the light that halogen tungsten lamp sends is through the reflection of optically focused lampshade, and its light all is focused on the emission focus, can make the light intensity of light source and colour temperature reach the strongest state.Because halogen tungsten lamp is the intense light source high brightness lamp, long time continuous working can produce very high heat, when temperature is too high, then power supply is produced impedance, thereby can cause voltage loss, reduce luminosity, the light intensity of influence emission light beam, this case the sidewall of light emitted case 101 respectively correspondence be provided with blast inlet 106 and heat radiation air outlet 103, and blower fan 105 is housed in the corresponding position of blast inlet 106, for making each heat radiation of light fixture evenly, alleviate directly blowing of blower fan wind-force, in the casing corresponding, be provided with wind-force cushioning fender 104 with blast inlet 106, this baffle plate can and wall box between form air intake passage, and on the circumferential wall of lamp socket 107, laid a plurality of heat radiation ventilating pits 108, can avoid illuminator overheated effectively, guarantee emission light intensity and stability.

Fig. 5 is the circuit of light sources connection diagram, and light source is the basis that produces the thickness optical signal, and is therefore very high to the power quality requirement that produces light, as: stability requirement voltage is not more than ± 1mV fluctuation in 10～20 seconds, and the voltage fluctuation in 1 hour is not more than ± 5mV; Ripple voltage Vrms≤1mV or the like.Therefore, for satisfying the requirement of light source stability, set up high performance constant electrical power control module at the Lights section of light projector.In the drawings, this circuit input power source voltage is AC220V, and by power supply input lead 111, through dc power module 112 and current sensor 114, making the lamp electric power output voltage is DC12V.Illuminator 102 is connected with constant electrical power control module 112 by lead, and what power module adopted is DC voltage stabilized source integration module.In addition, because of the work-ing life of illuminator 102 limited, even step-down is used, also have only several thousand hours, in the later stage in work-ing life, its luminescent properties then reduces greatly, can cause film thickness monitoring system that the false judgment of thickness signal is influenced monitoring effect.For can exact grasp and duration of service of control illuminator, in time change illuminator 102, to keep the plated film supervisory system in shape all the time, on illuminator 102, installed work timing register 116 additional, this timing register is made up of the current sensor 114, timing register interface 115 and the timing register 116 that connect successively, and wherein current sensor 114 is sleeved on the power lead 113.When power lights 102 work, the voltage signal of current sensor 114 output certain amplitude, timing register 116 picks up counting, and show the time with charactron, the maximum timing range of timing register is 9999.9 hours, can satisfy the work clocking requirement of illuminator 102, and the panel of timing register 116 is provided with the knob that resets, after changing the new light sources lamp, can be adjusted the writing time of timing register and return 0.

Be equipped with between modulator and the light emitted case and be used for heat insulation pillar 111, be used to avoid the influence of comparatively high temps that the light emitted case produces projecting beam.Described modulator comprises modulator housing 201, chopper wheel 202 and constant-seed motor 203, and chopper wheel 202 is contained in the housing 201, and constant-seed motor 203 is contained in outside the housing 201, and its output shaft is connected with chopper wheel 202 centers, the circumference uniform distribution rectangle unthreaded hole of chopper wheel 202.Chopper wheel 202 unthreaded holes adopt rectangular configuration, and the light wave curve after the modulation is the near sinusoidal curve, with the contrast gradient of enhancing signal peak value, realize the high resolving power of monitor signal.The constant-seed motor of installing has the at the uniform velocity effect of modulated light wave, by constant-seed motor 203, drive chopper wheel 202 and remain at the uniform velocity rotation, can avoid causing the ANOMALOUS VARIATIONS of emission optical signal frequency, thereby reach the best effect of modulated light wave frequency uniformity because of chopper wheel 202 revolution fluctuation.Output light source hole 204 ends with modulator, correspondence is connected with the optically focused lens barrel of being made up of lens barrel 301a, 301b, the combining site of two lens barrels connects by fastening piece, in lens barrel 301b, be provided with the focus lens assembly that can move axially adjusting, and correspondence is provided with adjustment hole 305 on the barrel of lens barrel 301b.Focus lens assembly is made up of condenser lens 304, lens permanent seat 302 and set screw 303, and condensing lens 304 is packed on the lens permanent seat 302, and the set screw 303 of installing on it is stretched out outside the adjustment hole 305.The light beam exit end of optically focused lens barrel 301b is fixed with positioning link 307 by ring flange 306, can be connected with the entrance pupil on the base plate in coating equipment evaporation chamber and communicate by positioning link 307, outgoing beam can be projected plated film in the evaporation chamber relatively on the sheet.Also can be connected with optical splitter 4 by positioning link 307, through reflector box 5 (referring to Fig. 1), the plated film that outgoing beam is projected in the evaporation chamber compares on the sheet by optical splitter 4.When light modulated bands of a spectrum range, can be by adjusting the position of mobile condensing lens 304, the hot spot that process is focused on all is incident upon plated film and compares on the sheet, and the luminance brightness that projects on the comparison sheet is strengthened, thereby can avoid because of the excessive light projector loss of signal that causes of focal beam spot disperse area, make the spot size that projects on the comparison sheet remain at optimum regime, and can improve the homogeneity and the stability of projection optical signal, improve the monitoring and the control effect of thickness with this.

Referring to Fig. 6, be the optical splitter formation synoptic diagram, in the reflected light path, the installation site of optical splitter is a forward type on up-set type, in the reflected light path, the installation site of optical splitter is rear-mounted under underneath type.Optical splitter comprises that being respectively equipped with optical signal on the tank wall of casing 401, light inlet slot dish 402a, bright dipping slit plate 402b, stepper-motor 403, grating assembly 404, casing 401 both sides goes into perforation 405 and optical signal delivery outlet 406, two hole corresponding positions are equipped with light inlet slot dish 402a and bright dipping slit plate 402b respectively, and the rotation of slit plate and spectro-grating 404 drives by stepper-motor.

Because the optical signal that lamp source produces is the whole chromatogram optical signal, wavelength region is at 380nm-1100nm, and film thickness gauge is used for monitoring the thicknesses of layers that is coated with, and need monitor at the monochromatic spectrum of rete.The effect of monochromator is to receive the relatively full spectral light signal of sheet reflection, enters after the monochromator, and the diffraction by monochromator splitting grating 404 produces the monochromatic spectrum optical signal and passes out to prime amplifier.Light inlet slot dish 402a, bright dipping slit plate 402b and spectro-grating 404 these three adjustable mechanisms are to finish automatic control by stepper-motor 403 and Stepping Motor Control circuit.

The rete parameter that is coated with at first as required preestablishes monochromator, and how many nm the spectrum of setting bright dipping slit sizes, light inlet slot size and the employing of monochromator is.Referring to Fig. 7, stepper-motor is connected with micro-chip U by driving mechanism, and carries out time variable control by computer.Send instruction by computer and pass through the RS232 serial ports to micro-chip U, respectively driving mechanism 1, driving mechanism 2, driving mechanism 3 are sent control wave after the micro-chip U decoding, by driver drives stepper-motor separately, reach preposition and stop operating, finish automatic setting to monochromator.

Referring to Fig. 8, Fig. 9, be the reflector box structural representation.Optical axis reflector box of the present invention has a casing 501 that has incident light through hole 509 and emergent light through hole 504, corresponding position with incident light through hole 509 and emergent light through hole 504 in the casing 501 is provided with a pair of optical surface incident/speculum, wherein, the optical signal that light incident mirror 508 is used for being injected by the outside light projector of mirrored cabinet reflexes to relatively sheet of plated film, forms the light emission path of emission optical signal; Light reflection mirror 505 is used for and will projects the photosignal transfer equipment that optical signal on the plated film comparison sheet reflexes to the mirrored cabinet outside, forms a luminous reflectance path with reflected light signal output.What be connected with light incident mirror 508 is microscope base 507, the microscope base that is connected with light reflection mirror 505 is 506, two microscope base lower surfaces are an inclined-plane, incident/speculum is packed in respectively on this inclined-plane, microscope base 506, the adjusting part that the mirrored cabinet peripheral hardware is useful on adjustment incident/mirror angle and upper-lower position is stretched out at 507 top, this assembly comprises tension spring regulating part 503 and three jackscrew regulating parts 502 that are used for adjusting angle of the upper-lower position regulated that is contained on the box body wall, microscope base 506,507 can realize the adjusting of microscope base upper-lower position respectively by tension spring regulating part 503, jackscrew regulating part 502 is connected by the upper wall of fastening piece with casing 501, the lower end holds out against on the upper surface of microscope base, by 502 3 effects of deciding face of jackscrew regulating part, can adjust the angle of incident/speculum easily.The adjusting part that is provided with not only can satisfy the upper-lower position of adjustment speculum and the requirement of angle, and incident optical signal can be incident upon exactly thus on the plated film comparison sheet, to reflex to exactly on the photosignal transfer equipment through the thickness optical signal of plated film comparison sheet reflection simultaneously, thereby monitor optical signal accurately for the thickness of monitoring plated film provides.

Referring to Figure 10, be photosignal conversion device structure synoptic diagram.The photosignal transfer equipment is to be made of optics mirrored cabinet 601 and conversion of signals case 609 two portions, conversion of signals case 609 is connected with the light beam exit end of optics mirrored cabinet 601 by fastening piece, optics mirrored cabinet 601 is packed in the light beam exit end of thickness optical signal transmission parts, be provided with the focus lens assembly that can move axially adjusting in the mirrored cabinet, this assembly comprises lens mount 602, condenser lens 604 and the set screw 603 of assembling successively.The corresponding elongated groove opening 612 that is used to regulate focus lens assembly that is provided with on the tank wall of optics mirrored cabinet 601.When the incident light wave bandwidth need change, to focus on by the directional light that the optical signal transmission isolation of components is come out by condenser lens 604, the light that the big I of focus disc of confusion is accepted senser element 605 according to light is accepted face and is determined that the focus point that can make throw light like this is all the time on the sensitive surface of transmitter.Be provided with the circuit card 606, circuit card bearing 607 and the bearing gland 608 that are used for the photosignal conversion in the conversion of signals case 609, the center of bearing has the photo-signal channel hole that is communicated with optics mirrored cabinet 601, can smear the extinction top layer on the passage hole wall, to avoid producing the quality that veiling glare influences optical signal.

In conjunction with Figure 10, referring to Figure 11, it is the circuit block diagram of photosignal conversion, among the figure, circuit on the photoelectric switching circuit plate 606 comprises: the light that is used to accept optical signal and be converted to electrical signal is accepted senser element 605, ac signal is transformed to the I/V translation circuit 613 of the big multiplying power of dc signal, the prime amplifier 614 that the voltage signal that the I/V translation circuit is exported tentatively amplifies, each components and parts all is contained on the circuit card, and, the signal handling equipment of signal transmission line with conversion of signals casing 609 outsides is connected by the terminal stud on the casing 610,611.Be to improve the efficiency of conversion of thickness signal, what be contained in that light on the circuit card 606 accepts that senser element 605 adopts is highly sensitive, the silicon photo diode that can adapt to different wide wavelength regions.Because the light beam that light source sends is through the conduction of long distance and the reflection of plated film, the optical signal that is transmitted on the transmitter is very faint, the electric current that produces on transmitter only can reach pA～nA order of magnitude, adopts common series resistance to obtain voltage method and can't measure the signal variation at all.Therefore, the photosignal change-over circuit of this case is the I/V translation circuit 613 that has connected a big multiplying power at the signal output part that light is accepted senser element 605, can make the output voltage of the corresponding 20mV of received current of 100pA.Simultaneously, connected a prime amplifier 614 at I/V translation circuit output terminal, can the signal voltage of I/V translation circuit output tentatively have been amplified, prime amplifier adopts the sign reversing amplifier of accurate amplifier, can gain about 50 times.Like this,, make the output voltage of photoelectric commutator can reach 1500mV, thereby create favorable conditions for the subsequent disposal of signal corresponding to the photoelectric current of 100pA.The conventional DC power supply can be directly used in employing sort circuit design, and not only safe reliability is strong, and can simplified construction, reduces cost.

As shown in figure 12, be the circuit block diagram of signal processing unit.Photoelectric switching circuit in the photosignal transfer equipment with electrical signal converted carry out preposition after, after signal processing unit processes, import computer again.As shown in figure 12, signal processing unit is connected to form successively by programmable amplifier, wave filter, alternating current amplifier, absolute value rectifying circuit, direct-current amplifier, A/D transition card, the input terminus of programmable amplifier is connected with the output terminal of photosignal transfer equipment, and the output terminal of A/D transition card is connected with computer.Described programmable amplifier also is connected with micro-chip U, is used to accept the gain control signal that micro-chip U sends.

Because detected weak signal amplitude can change.Requirement according to plated film, sometimes need the monochromator output wavelength is selected, the corresponding different wavelength of photorectifier has different efficiency of conversion, and the electric current of photorectifier output also changes thereupon, and this adjusts with regard to the enlargement ratio that requires pair amplifier.Programmable amplifier is made up of two digits potentiometer 1, digital regulation resistance 2 and two-stage calculation amplifier 1, the operational amplifier 2 of micro-chip U control, and as shown in figure 13, it is to utilize computer to adjust the enlargement ratio of amplifier automatically.This inflation method is by the communications protocol between main control computer and the micro-chip U, and the program of calling micro-chip U inside is provided with digital regulation resistance, by changing the purpose that the digital regulation resistance value reaches the enlargement ratio of adjusting operational amplifier.

The noise of coating system is mainly derived from two aspects: 1. the noise that brings of light source: the plated film electron gun is opened the light that the back produces and is disturbed, interfering frequency be at random and luminance brightness very high.2. the noise that produces of circuit itself: this noise is not the noise that is brought by circuit production method or outside interference such as electromagnetic field, but the noise that device insides such as operational amplifier and resistance produce, this noise is called intrinsic noise from the meaning of essence, and uniform distribution all on any frequency, this characteristic becomes white Gaussian noise.For this reason, need carry out filtering to signal.Median filter of the present invention adopts eight rank bandpass filter.Shown in Figure 14 is a MAX274 second-order filter unit, and eight rank wave filters are to be formed by 4 second-order filter unit combination.By design requirements, parameters such as mid-frequency Fc, the passband top width Fbw of eight rank wave filters, passband bottom width Fsw, passband fluctuation Amax, attenuation outside a channel Amin are carried out correct design, input obtains the unitary mid-frequency of each second-order filter, Q value behind the design variable, and the resistance of each second-order filter unit peripheral components R1, R2, R3, R4.

Bandpass filter is used for selecting the modulating frequency of modulator, the interference that filtering veiling glare and circuit produce.Because modulator adopts synchronous machine drives, frequency is very steady, thus can be very narrow getting of the bandwidth Design of this grade wave filter, the garbage signal beyond the modulator modulating frequency is produced very big inhibition, thereby obtain cleaner useful signal.In traditional film thickness gauge circuit, use second order filter and phase-locked loop circuit to come treatment circuit noise and frequency error, but still be not enough on the noise processed ability, influenced the stability of output signal.Can realize very narrow frequency span, smooth passband fluctuation, great attenuation outside a channel by eight rank wave filters, thereby suppress noise most effectively.

The absolute value rectifying circuit is the accurate absolute value circuit that is made of amplifier, makes the AC signal of input intactly be transformed to the pulsating direct current signal, finishes the conversion work of AC-to DC.Direct-current amplifier further amplifies the direct current signal of absolute value circuit output, to satisfy the needed dc level signal of A/D transition card.

Optical coating film thickness monitoring method of the present invention may further comprise the steps:

1, at first imports in the computer of blooming controller, form the technical papers of preparing plated film according to design document as TFCalc and Essential Macleod software;

2, after the vacuum system of coating equipment is ready to complete, when can begin plated film, the user begins to carry out evaporation operation (click and carry out technology) in control computer;

3, before the beginning evaporation, computer is according to processing requirement, system (is transformed into supervisory wavelength 600nm as needs by the serial port control single chip computer, then send to serial port command string m100600 (sexadecimal number system 0d), then SCM system begins to send turn signal later on receiving order, the control step motor begins rotation, rotates to specified supervisory wavelength then), supervisory wavelength value and spectral filter (being used to filter secondary light) are set;

4, computer is gathered the voltage change signal (corresponding light value variable signal) that amplifying circuit amplifies by computer A/D capture card, and be converted to reflectivity, according to difference when the anterior layer Coating Materials, different gains is set (sends serial port command to micro-chip U, as gain is 30, then send serial port command m230 (sexadecimal number system 0d), micro-chip U is after detecting this order, send order to digital regulation resistance, and regulate the resistance of digital regulation resistance, circuit is converted to change in gain according to change in resistance;

5, send the order of conversion crucible to the crucible controller, crucible rotating. to the given process position, two cover crucibles about control, every cover crucible is made up of several crucibles, each crucible is placed different coating materials, and computer sends binary-coded decimal by the IO port and carries out the crucible switching;

Illustrate

6, by IO port output pulse signal, control coating equipment electron beam gun is opened, and opens line by another one IO port, beginning fritting operation; According to the user in film thickness gauge, set 5 sections pre-process of smelting, computer is by the line value of D/A conversion output electron beam gun, the automatically pre-process of smelting that begins to be scheduled to;

7, after fritting is finished, give brilliant control with the electron beam gun control and carry out line control, the announcing circuit transfer relay switches to brilliant control with control signal, brilliant control will be carried out vaporator rate control according to the rate-controlling order that film thickness gauge sends by serial ports: (send serial port command by the RS232 serial port, according to the difference of crystalline substance control, serial port command is also inequality);

8, send beginning plated film signal at film thickness gauge, when detecting the signal of opening baffle plate, film thickness gauge begins the capture card according to A/D, detects the variation of light value, and real-time curve is presented on the screen;

9, computer software calculates according to the variation of light value, and when calculating evaporation when proceeding to peak point, calculate real-time specific refractory power automatically, and revise the arrests light value automatically, and revised theory curve automatically;

10, evaporation is proceeded, and according to the evaporation process that sets in advance, when the A/D capture card received precalculated arrests voltage, computer sent and closes the baffle plate order, and notice sends the brilliant control of order control by serial ports, stops the evaporation of this layer;

11, this layer stops, and according to the requirement of technology evaporation state, whether begins to descend the evaporation of one deck automatically, if auto begins, so just begins the order of evaporation continuation transmission evaporation and begins to be coated with down one deck, repeats 3～10 operation, stops up to all technologies.

Claims (10)

1. optical coating film thickness monitoring automatic control system, it is characterized in that, it comprises light projector device, optical splitter, the photosignal transfer equipment, signal processing unit and computer, light projector device directly be connected with the light entrance port of coating equipment or and optical splitter, reflector box connects and is used for the light that light projector device sends is throwed into coating equipment, the optical emission exit of coating equipment connects an optical communication means and is connected with the light entrance port of optical splitter, the optical emission exit of optical splitter is connected with the light entrance port of photosignal transfer equipment again, perhaps the emergent ray of coating equipment reflects light into the photosignal transfer equipment by reflector box, and the electrical signal of photosignal transfer equipment is connected with computer by signal processing unit.

2. optical coating film thickness monitoring automatic control system as claimed in claim 1, it is characterized in that, described film thickness monitoring automatic control system adopts reflected light path on the up-set type, light projector device, optical splitter, reflector box, photosignal transfer equipment are formed incident/reflected light path, after assembling successively, each parts is contained in the top in coating equipment evaporation chamber, it is incident optical signal to be projected plated film compare on the sheet, and forms the light emission path of emission optical signal thus; The optical signal that will be projected on the plated film comparison sheet by light reflection mirror reflexes on the photosignal transfer equipment that is connected with this mirrored cabinet again, forms a luminous reflectance path with reflected light signal output.

3. optical coating film thickness monitoring automatic control system as claimed in claim 1, it is characterized in that, described film thickness monitoring automatic control system adopts reflected light path under the underneath type, light projector device is installed in the bottom in coating equipment evaporation chamber and forms input path, it is incoming beam to be projected plated film compare on the sheet, and forms the light emission path of emission optical signal thus; Optical splitter and connected photosignal transfer equipment are contained in the bottom in coating equipment evaporation chamber, and optical splitter is connected with coating equipment evaporation chamber optical emission exit by optical cable and fiber cable joint, forms the luminous reflectance path thus.

4. optical coating film thickness monitoring automatic control system as claimed in claim 1, it is characterized in that, described film thickness monitoring automatic control system adopts the transmission-type light path, its light entrance port and optical emission exit are in the corresponding setting of coating equipment evaporation chamber upper and lower ends, light projector device is installed in the bottom or the top in coating equipment evaporation chamber and forms input path, it projects plated film by the light entrance port with incoming beam compares on the sheet, and forms the light emission path of emission optical signal thus; Optical splitter adopts optical cable and is installed in coating equipment evaporation top of chamber or the bottom corresponding with launching light path by fiber cable joint, and be connected with the photosignal transfer equipment, be used to accept to project the relatively light transmission signal on the sheet of plated film, form one and will launch the transmission path that optical signal is exported.

5. as claim 1,2,3 or 4 described optical coating film thickness monitoring automatic control systems, it is characterized in that, described light projector device is by the light emitted case, modulator, the optically focused lens barrel is formed, in the light emitted case, be provided with the tungstohalogen lamp of band optically focused lampshade, casing one side connects the modulator of a band constant-seed motor by pillar, the output light source end correspondence of modulator is connected with the optically focused lens barrel, be provided with the focus lens assembly that can move axially adjusting in the lens barrel, the light beam output terminal of optically focused lens barrel is equipped with positioning link by ring flange, described tungstohalogen lamp is by halogen tungsten lamp, the optically focused lampshade and the lamp socket that have ellipsoid are formed, the caustic surface of optically focused lampshade is towards the optical channel of lamp socket, and link to each other with the lamp socket spiral-lock, the center of lamp socket is the cavity with optical channel, and communicate with the light source perforation hole that is provided with on the casing antetheca, lamp socket is an inclined-plane towards the end face of light source, halogen tungsten lamp and lampshade are tilting to be installed on this inclined-plane, angle α between the optically focused optical axis of described optically focused lampshade and the emergent light axis of light beam perforation hole is 10～30 °, described modulator is by the modulator housing, chopper wheel and constant-seed motor are formed, chopper wheel is contained in the housing, constant-seed motor is contained in outside the housing, its output shaft is connected with the chopper wheel center, the circumference uniform distribution rectangle unthreaded hole of chopper wheel, described focus lens assembly is by condensing lens, the lens permanent seat, set screw is formed, the barrel of described optically focused lens barrel is provided with and is used to regulate the axially movable adjustment hole of focus lens assembly, condensing lens is packed on the lens permanent seat, and the set screw of installing on it is stretched out outside the adjustment hole.

6. as claim 1,2,3 or 4 described optical coating film thickness monitoring automatic control systems, it is characterized in that: described photosignal transfer equipment is made of optics mirrored cabinet and conversion of signals case two portions, combining site between the two connects by fastening piece, wherein, the optics mirrored cabinet is positioned at the light beam exit end of thickness optical signal transmission parts, be provided with the focus lens assembly that can move axially adjusting in it, be provided with photosignal change-over circuit plate in the conversion of signals case by seat supports, casing is provided with terminal stud, the center of bearing has the photo-signal channel hole that is communicated with the optics mirrored cabinet, described focus lens assembly is the condenser lens of assembling by successively, the lens permanent seat, set screw is formed, and is arranged with on the tank wall of described optics mirrored cabinet to be used to regulate the axially movable elongated groove opening of focus lens assembly.

7. optical coating film thickness monitoring automatic control system as claimed in claim 6 is characterized in that: described photosignal change-over circuit comprises: a light is accepted senser element, is used to accept optical signal and is converted to electrical signal; The I/V translation circuit of a big multiplying power is used for ac signal is transformed to dc signal; A prime amplifier is used for the voltage signal of I/V translation circuit output is tentatively amplified.

8. as claim 1,2,3 or 4 described optical coating film thickness monitoring automatic control systems, it is characterized in that: described reflector box has a casing that has incident light through hole and emergent light through hole, corresponding position with incident light through hole and emergent light through hole in the casing is provided with a pair of optical surface incident/speculum, what be connected with this incident/speculum is that the lower surface is the microscope base on an inclined-plane, the top of microscope base is provided with stretches out the outer adjusting part that is used to adjust incident/mirror angle and upper-lower position of mirrored cabinet, described adjusting part comprises the tension spring regulating part of the upper-lower position regulated that is contained on the box body wall and is used for the jackscrew regulating part of adjusting angle that jackscrew regulating part and microscope base upper end touch.

9. according to claim 1,2,3 or 4 described optical coating film thickness monitoring automatic control systems, it is characterized in that: described signal processing unit is connected to form successively by programmable amplifier, wave filter, alternating current amplifier, absolute value rectifying circuit, direct-current amplifier, A/D transition card, the input terminus of programmable amplifier is connected with the output terminal of photosignal transfer equipment, the output terminal of A/D transition card is connected with computer, described programmable amplifier also is connected with micro-chip, is used to accept the gain control signal that micro-chip sends.

10. optical coating film thickness monitoring method is characterized in that it may further comprise the steps:

(1), after the vacuum system of coating equipment is ready to complete, can begin plated film in, carry out the evaporation operation;

(2), before the beginning evaporation, computer is according to processing requirement, send the wavelength monitor order by serial port to single-chip computer control system, SCM system begins later on to send turn signal to the stepper-motor of optical splitter receiving order, the control step motor rotates to specified supervisory wavelength, and the supervisory wavelength value is set;

(3), the voltage change signal that amplifies by computer A/D capture card acquired signal processing unit of computer and be converted to reflectivity, according to difference when the anterior layer Coating Materials, different amplifier gains is set, SCM system is after detecting this order, send order to digital regulation resistance, and regulate the resistance of digital regulation resistance, circuit is converted to change in gain according to change in resistance;

(4), computer sends the order of conversion crucible to the crucible controller, crucible rotating is to the given process position, and two overlap crucibles about control, and every cover crucible is made up of several crucibles, each crucible is placed different coating materials, and computer sends binary-coded decimal by the IO port and carries out the crucible switching;

(5), computer is by IO port output pulse signal, control coating equipment electron beam gun is opened, open line by another one IO port, beginning fritting operation, five sections pre-process of smelting in film thickness gauge, setting according to the user, computer is changed the line value of exporting electron beam gun by D/A, the automatically pre-process of smelting that begins to be scheduled to;

(6), after fritting is finished, give brilliant control with the electron beam gun control and carry out line control, the announcing circuit transfer relay switches to brilliant control with control signal, brilliant control will be carried out vaporator rate control according to the rate-controlling order that film thickness gauge sends by serial ports;

(7), send beginning plated film signal, COMPUTER DETECTION is when opening the signal of baffle plate, and beginning is according to the variation of A/D capture card detection light value, and real-time curve is presented on the screen at film thickness gauge;

(8), computer calculates according to the variation of light value, when calculating evaporation when proceeding to peak point, calculate real-time specific refractory power automatically, and revise the arrests light value automatically, and revised theory curve automatically;

(9), evaporation proceeds, according to the evaporation process that sets in advance, when the A/D capture card received precalculated arrests voltage, computer sent and closes the baffle plate order, and notice sends the brilliant control of order control by serial ports, stopped the evaporation of this layer;

(10), according to the requirement of technology evaporation state, judge whether to begin automatically to descend the evaporation of one deck, if begin automatically, continue to send the evaporation order and begin to be coated with down one deck, the operation of repeating step 2～10 stops up to all technologies.

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