CN101839695A - Method for measuring thickness of LED type solid infrared thin film - Google Patents
Method for measuring thickness of LED type solid infrared thin film Download PDFInfo
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- CN101839695A CN101839695A CN 201010208325 CN201010208325A CN101839695A CN 101839695 A CN101839695 A CN 101839695A CN 201010208325 CN201010208325 CN 201010208325 CN 201010208325 A CN201010208325 A CN 201010208325A CN 101839695 A CN101839695 A CN 101839695A
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Abstract
The invention discloses a method for measuring the thickness of an LED type solid infrared thin film, belonging to the optical measurement field for the thickness of a plastic thin film. The invention solves the problems that the traditional infrared transmission method for measuring the thickness of the thin film has great measurement error and low response speed. In the method, an absorbent light LED in the control of a light source modulation circuit outputs light pulse with the wavelength of 3.4 microns; a reference light LED controlled by a light source modulation circuit outputs the light pulse with wavelength of 3.1 mu m; two paths of the lights with different wavelengths are irradiated on the same position of the thin film at the same time; a PbSe sensor absorbs two paths of the lights transmitting the thin film and outputs a voltage signal; in the control of the synchronous control signals output by the light source modulation circuit, a signal computation and processing unit receives the voltage signal and acquires the thickness information according to the received voltage signal. The method of the invention is applied to the online measurement of the thickness of the thin film.
Description
Technical field
The present invention relates to the solid-state infrared measured film thickness method of LED formula, belong to optical field.
Background technology
In the production run of film, the on-line measurement of film thickness is quite important.On production line, mylar is vertically walked, and obtains the thickness of each position of film by measuring sonde.Known usual thickness measuring method has rays method, supercritical ultrasonics technology, IR transmission method etc. at present.IR transmission method occupies dominant position for a long time as a kind of traditional method for measuring thickness in the thickness measure of mylar.
Conventional red outside line transmission thickness measuring method adopts the halogen bulb as light source 1, and referring to shown in Figure 1, light is converged to directional light to chopper wheel 3 through lens, and chopper wheel 3 is equipped with the measurement wavelength respectively
Optical filter 4 and measure reference wavelength
Optical filter 5, drive the source of parallel light that chopper wheels 3 cuttings see through by synchronous motor 6 again, two monochromic beam pulses after filtering are irradiate 7 alternately, after film 7 absorbed, transmitted light gathered P
bOn the S sensor 8, and be transformed into electric signal and deliver to signal operation and processing unit 9, finally demonstrate the actual measurement one-tenth-value thickness 1/10 of tested mylar 7 by thickness display instrument 10.
Two wavelength infrared lights of conventional red outside line thickness measuring method are obtained by chopper wheel 3 rotation modulation, because the modulating frequency low (greatly about about 60Hz) of chopper wheel 3, so there are certain phase difference in time in measuring light and reference light.And biaxially oriented film and casting films are moved with the speed more than the 300m/min usually, therefore two bundle infrared wavelengths are not really to be radiated at the same area, promptly have certain skew on the measurement space of film 7, this will cause the error of measurement, and response speed is reduced.In addition, the mechanical motion of chopper wheel 3 also can increase the error of system, reduces the reliability of system.
Summary of the invention
The present invention seeks to adopt traditional problem that IR transmission method MEASUREMENTS OF THIN thickness measure error is big, response speed is low, provide a kind of LED formula solid-state infrared measured film thickness method in order to solve.
Method of the present invention is:
The light pulse of absorbing light LED output wavelength 3.4 μ m under the control of modulation of source circuit, the light pulse of reference light LED back output wavelength 3.1 μ m under the control of modulation of source circuit, the light of described two-way different wave length is beaten simultaneously on the same position of film, the two-way light that sees through film is absorbed and output voltage signal by the PbSe sensor, signal operation and processing unit receive described voltage signal under the control of the synchronous control signal of modulation of source circuit output, signal operation and processing unit obtain the thickness information of film according to the voltage signal that receives.
Advantage of the present invention: the solid-state infrared measured film thickness instrument of LED formula that this patent proposes is according to the infrared energy principle of absorption, adopt double light path design, solid-state light electric transducer, by the relatively signal variation of absorbing wavelength and reference wavelength, measure the thickness of film exactly.Overcome the phase differential problem of thickness measure in the high speed, serialization production run of biaxially oriented film and casting films, improved precision, response speed and the reliability of thickness measuring system significantly.The temperature, humidity, air pressure, dust and the film stretching direction that also have environment of this infrared gauge is insensitive, reliable simultaneously, the easy-to-install advantage.
Description of drawings
Fig. 1 is a conventional red outside line thickness measuring method schematic diagram in the background technology, Fig. 2 is the schematic diagram of MEASUREMENTS OF THIN thickness approach of the present invention, Fig. 3 is the schematic diagram that signal operation and processing unit obtain film thickness information, Fig. 4 is the light pulse signal synoptic diagram of 3.1 μ m, Fig. 5 is the light pulse signal synoptic diagram of 3.4 μ m, and Fig. 6 is the light signal synoptic diagram that signal operation and processing unit extract.
Embodiment
Embodiment one: below in conjunction with Fig. 1 to Fig. 6 present embodiment is described, present embodiment is:
The light pulse of absorbing light LED2 output wavelength 3.4 μ m under the control of modulation of source circuit 1, the light pulse of reference light LED3 back output wavelength 3.1 μ m under the control of modulation of source circuit 1, the light of described two-way different wave length is beaten simultaneously on the same position of film 4, the two-way light that sees through film 4 is absorbed and output voltage signal by PbSe sensor 5, signal operation and processing unit 6 receive described voltage signal under the control of the synchronous control signal of modulation of source circuit 1 output, signal operation and processing unit 6 obtain the thickness information of film 4 according to the voltage signal that receives.Signal operation and processing unit 6 are exported to thickness display instrument 7 with described thickness information and are shown.
The native system light source adopts GaSb-InAs infraluminescence pipe, replace traditional β ray type sensor or halogen light source, the Main Ingredients and Appearance of film 4 is-the CH-group, adopt right-CH-group to have 3.4 mum wavelengths of strong absorption as absorbing wavelength to film 4,3.4 the oscillogram of mum wavelength light pulse as shown in Figure 5, select for use simultaneously non-absorbent substantially 3.1 mum wavelengths of film 4 as reference wavelength, the oscillogram of 3.1 mum wavelength light pulses as shown in Figure 4.3.4 the degree of the light transmission film 4 of mum wavelength is little, PbSe sensor 5 is to its induction, the intensity of the light signal that produces is just little, and the degree of the light transmission film 4 of 3.1 mum wavelengths is big, PbSe sensor 5 is to its induction, the intensity of the light signal that produces is big, after two-way light pulse after the modulation penetrates tested film respectively, by PbSe sensor 5(vulcanized lead) receive, and convert it into photo-signal, handled by signal operation and processing unit 6, calculate the thickness of film 4, the voltage signal that signal operation and processing unit 6 extract the two-way light pulse as shown in Figure 6.According to as can be known aforementioned, 3.4 the light transmission rate of mum wavelength is low, 3.1 the light transmission rate of mum wavelength is low, one group of waveform that amplitude is big among Fig. 6 is the voltage signal U1 of corresponding 3.1 mum wavelength light pulses, and one group of waveform that amplitude is little is the voltage signal U2 of corresponding 3.4 mum wavelength light pulses.By the relatively signal variation of absorbing wavelength and reference wavelength, just can obtain the one-tenth-value thickness 1/10 of film 4.Concrete computation process is as follows:
If the thickness of tested film 4 is D, it obtains by following formula:
D=K*(U1-U2)/U1。
Wherein K is a calibration coefficient, is D by measuring a known thickness
0The standard film obtain, be specially: K=D
0* U1
0/ (U1
0-U2
0), U1
0For thickness is D
0The voltage signal of the corresponding 3.1 mum wavelength light pulses of standard film, U2
0For thickness is D
0The voltage signal of the corresponding 3.4 mum wavelength light pulses of standard film.
The inventive method adopts the electronics modulation system, and with traditional single halogen light source, the method for chopper wheel modulation is compared, and has cancelled mechanical dynamic modulation mechanism, thereby has improved precision, stability and the response speed measured, has also improved the reliability of system simultaneously.By the designed measured film thickness instrument of this patent method can high precision, the thickness distribution of high speed and online reliably detection biaxially oriented film and casting films.
Absorbing light LED2 and reference light LED3 adopt GaSb-InAs infraluminescence pipe.
Because the LED luminotron is relatively more responsive to variation of temperature, thus must control its temperature, to guarantee LED luminotron output light wavelength and stabilized intensity.Absorbing light LED2, reference light LED3 and PbSe sensor 5 be all supporting to be provided with a temperature control circuit 8.
The process that signal operation and processing unit 6 obtain the thickness information of film 4 is: the electric signal of PbSe sensor 5 outputs is at first carried out preposition processing and amplifying, under the control of the synchronous control signal of modulation of source circuit 1, the signal after the processing and amplifying is carried out synchronous integration then, extract the signal of corresponding two-way different wave length light pulse, carry out filtering, rectification then, carry out the A/D conversion process again, carry out calculation process by DSP at last, obtain the thickness information of film 4.
Claims (4)
1. solid-state infrared measured film thickness method of LED formula is characterized in that this method is:
Absorbing light LED(2) light pulse of output wavelength 3.4 μ m under the control of modulation of source circuit (1), reference light LED(3) light pulse of back output wavelength 3.1 μ m under the control of modulation of source circuit (1), the light of described two-way different wave length is beaten simultaneously on the same position of film (4), the two-way light that sees through film (4) is absorbed and output voltage signal by PbSe sensor (5), signal operation and processing unit (6) receive described voltage signal under the control of the synchronous control signal of modulation of source circuit (1) output, signal operation and processing unit (6) obtain the thickness information of film (4) according to the voltage signal that receives.
2. the solid-state infrared measured film thickness method of LED formula according to claim 1 is characterized in that absorbing light LED(2) and reference light LED(3) employing GaSb-InAs infraluminescence pipe.
3. the solid-state infrared measured film thickness method of LED formula according to claim 1, it is characterized in that, absorbing light LED(2), reference light LED(3) and all supporting temperature control circuit (8) that is provided with of PbSe sensor (5), keep absorbing light LED(2), reference light LED(3) and the working temperature of PbSe sensor (5) stablize.
4. the solid-state infrared measured film thickness method of LED formula according to claim 1, it is characterized in that, the process that signal operation and processing unit (6) obtain the thickness information of film (4) is: the electric signal of PbSe sensor (5) output is at first carried out preposition processing and amplifying, under the control of the synchronous control signal of modulation of source circuit (1), the signal after the processing and amplifying is carried out synchronous integration then, extract the signal of corresponding two-way different wave length light pulse, carry out filtering then, rectification, carry out the A/D conversion process again, carry out calculation process by DSP at last, obtain the thickness information of film (4).
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102183207A (en) * | 2011-02-23 | 2011-09-14 | 中国科学院上海光学精密机械研究所 | Device for measuring thickness and uniformity of fluorescent powder of energy saving lamp |
| CN102538688A (en) * | 2011-12-26 | 2012-07-04 | 哈尔滨工业大学 | Infrared broadband transmission type plastic film thickness measuring device and infrared broadband transmission type plastic film thickness measuring method |
| CN102980521A (en) * | 2012-10-25 | 2013-03-20 | 上海宏昊企业发展有限公司 | Thick-thin dual-purpose plating thickness measurer |
| CN103673903A (en) * | 2013-12-23 | 2014-03-26 | 清华大学 | Film thickness measurement device |
| CN106403829A (en) * | 2016-09-05 | 2017-02-15 | 南通大学 | Dual-optical path infrared reflection method-based coating thickness gauge |
| CN106441124A (en) * | 2016-10-14 | 2017-02-22 | 昆明理工大学 | Novel method for measuring film thickness by time response based on laser-induced thermoelectricity voltage |
| CN108801194A (en) * | 2018-08-02 | 2018-11-13 | 广州市盛华实业有限公司 | A kind of non-contact powder wet film thickness gauge |
| CN108844473A (en) * | 2018-04-19 | 2018-11-20 | 嘉善卡勒机车零部件有限公司 | The detection device of locomotive element processing |
| CN108303437B (en) * | 2018-04-02 | 2024-02-23 | 中国科学技术大学 | Online research system for combination of multi-scale structure detection unit and film biaxial stretching device |
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Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102183207A (en) * | 2011-02-23 | 2011-09-14 | 中国科学院上海光学精密机械研究所 | Device for measuring thickness and uniformity of fluorescent powder of energy saving lamp |
| CN102183207B (en) * | 2011-02-23 | 2012-08-29 | 中国科学院上海光学精密机械研究所 | Device for measuring thickness and uniformity of fluorescent powder of energy saving lamp |
| CN102538688A (en) * | 2011-12-26 | 2012-07-04 | 哈尔滨工业大学 | Infrared broadband transmission type plastic film thickness measuring device and infrared broadband transmission type plastic film thickness measuring method |
| CN102980521A (en) * | 2012-10-25 | 2013-03-20 | 上海宏昊企业发展有限公司 | Thick-thin dual-purpose plating thickness measurer |
| CN102980521B (en) * | 2012-10-25 | 2015-04-22 | 上海宏昊企业发展有限公司 | Thick-thin dual-purpose plating thickness measurer |
| CN103673903A (en) * | 2013-12-23 | 2014-03-26 | 清华大学 | Film thickness measurement device |
| CN106403829B (en) * | 2016-09-05 | 2018-09-07 | 南通大学 | Coating thickness detector based on double light path infrared reflection method |
| CN106403829A (en) * | 2016-09-05 | 2017-02-15 | 南通大学 | Dual-optical path infrared reflection method-based coating thickness gauge |
| CN108759689A (en) * | 2016-09-05 | 2018-11-06 | 南通大学 | The thickness measuring method of coating thickness detector based on double light path infrared reflection method |
| CN108759691A (en) * | 2016-09-05 | 2018-11-06 | 南通大学 | The thickness measuring method of the coating thickness detector based on double light path infrared reflection method of good working effect |
| CN108759690A (en) * | 2016-09-05 | 2018-11-06 | 南通大学 | The coating thickness detector based on double light path infrared reflection method of good working effect |
| CN108759689B (en) * | 2016-09-05 | 2019-12-17 | 南通大学 | coating thickness meter based on double-light-path infrared reflection method |
| CN106441124A (en) * | 2016-10-14 | 2017-02-22 | 昆明理工大学 | Novel method for measuring film thickness by time response based on laser-induced thermoelectricity voltage |
| CN108303437B (en) * | 2018-04-02 | 2024-02-23 | 中国科学技术大学 | Online research system for combination of multi-scale structure detection unit and film biaxial stretching device |
| CN108844473A (en) * | 2018-04-19 | 2018-11-20 | 嘉善卡勒机车零部件有限公司 | The detection device of locomotive element processing |
| CN108801194A (en) * | 2018-08-02 | 2018-11-13 | 广州市盛华实业有限公司 | A kind of non-contact powder wet film thickness gauge |
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Open date: 20100922 |