CN101498659A - Power self-calibration anti-fake holographical identification characteristic parameter detection method and detector - Google Patents

Abstract

The invention discloses an apparatus for automatically calibrating power and detecting holographic anti-counterfeiting label characteristic parameters and a method for detecting the same. The method comprises the steps of utilizing a second photoelectric receiver to obtain multi-point diffracted light intensity signals in the scanning direction in time, calibrating the intensity of incident light on the surface of the holographic anti-counterfeiting label after a first photoelectric receiver synchronously detects light intensity signals in the reflection direction of a light splitting substrate at the time when the first photoelectric receiver detects the intensity of the diffracted light at all points, analyzing and processing data with an embedded system after two ways of light intensity signals are converted to voltage signals by the photoelectric receivers, and calculating the characteristic parameters including the signal to noise ratio and the diffraction efficiency of the detected holographic anti-counterfeiting label. The apparatus comprises a light source, a mechanical mechanism, the photoelectric receivers, a signal amplifying module, an analog-to-digital conversion module, a central control module, a displaying module and a USB flash disk access module. The invention ensures that the process of detecting holographic anti-counterfeiting label characteristic parameters is easy and rapid and has strong operability. Compared with the first-generation apparatus for detecting, the apparatus greatly reduces the cost and the volume and is more favorable for the popularization of the product and the technology.

Description

Power self-calibration anti-fake holographical identification characteristic parameter detection method and detector

[technical field]:

The present invention relates to the detection technique field of anti-fake holographical identification quality, particularly to its characterisitic parameter: the measurement of diffraction efficiency and signal to noise ratio (S/N ratio).

[background technology]:

Anti-fake holographical identification is the safety anti-fake product based on laser holographic plate-making technology and moulding replication technology, usually is used for the safety anti-fake of product.The quality of anti-fake holographical identification should reach certain requirement to reach false proof effect.Anti-fake holographical identification characteristic index detector is applied to detect the anti-fake holographical identification characteristic parameter index: diffraction efficiency and signal to noise ratio (S/N ratio).But this instrument monitoring laser rainbow mould pressing holographic anti-counterfeiting logo product quality is for technical supervision department is checked on and manufacturer carries out and implements " anti-counterfeiting holographic product current techique " national standard quantitative means of testing is provided.

First generation anti-fake holographical identification characteristic parameter detector, signal and noise for gathering can read and record automatically by system, go out diffraction efficiency and signal to noise ratio (S/N ratio) by COMPUTER CALCULATION, realized automatic measurement, certain progress has been arranged with respect to the method for manual measurement to characterisitic parameter.

But first generation anti-fake holographical identification parameter detecting instrument also exists very big deficiency, and especially its detection method is very high to the laser output power stability requirement, causes its manufacturing cost very high.The medium and small sized enterprises that manufacturing enterprise especially quantitatively has comparative advantage are difficult to utilize expensive first generation detector to realize the product quality self check.In addition, because first generation anti-fake holographical identification parameter detecting instrument will use a computer and carry out data processing and demonstration,, and testing staff's operative skill had relatively high expectations so system bulk is bigger.These deficiencies make the application of detection method and detector universally has been subjected to very big restriction.

[summary of the invention]:

The present invention seeks to overcome existing holographic anti-counterfeiting label detector cost height, volume is big, be unfavorable for the novel detection method that a kind of measuring error is little, cost is low being provided the problem promoted, and developing cheap new pattern laser holographic anti-counterfeiting label characterisitic parameter detector.

The present invention proposes the holographic anti-counterfeiting label characteristic parameter detection method that the surperficial incident optical power of a kind of sign to be measured can be calibrated automatically, and develops the embedded detector of this method of realization.

This method adopt luminous power instability be 5% He-Ne laser instrument as light source, not high to the source device output optical power stability requirement, greatly reduce instrument cost; Displacement mechanism drives example platform to carry out one dimension displacement and moves and realize one dimension autoscan function to anti-fake holographical identification; The collection of data and processing are finished by embedded system, automatically calculate the characterisitic parameter of anti-fake holographical identification to be measured, and directly by the LCD display result, can realize simultaneously the USB flash disk access of data, make measuring process easy, quick, workable, reduced technical ability requirement the testing staff.And compare first generation detector, cost and volume reduce greatly, more help the popularization of product and technology.

Measuring principle is to utilize signal light intensity, the noise light intensity of measuring in the rainbow hologram slit image diffractogram, and the light intensity that incides the anti-counterfeiting mark surface, calculates anti-counterfeiting mark signal to noise ratio (S/N ratio) and diffraction efficiency characterisitic parameter.

In order to reduce the measuring error that He-Ne laser instrument Output optical power instability causes, reduce requirement to the source device output optical power degree of stability, we carry out real-time synchro measure to playback light and diffraction light.Between laser instrument and sample stage, added a branch light substrate angled with the laser beam direction of propagation.When laser instrument incides on the substrate at a certain angle, substrate is certain to the saturating inverse ratio of laser beam, can calculate the transmitted light intensity that laser instrument is exported the light transmission substrate to laser instrument output reflection of light light intensity by measuring substrate, promptly incide the reproduction light intensity on the sample.Simultaneously, adopt the identical photodetector of two-way to survey the diffraction intensity that substrate produces behind the sample the reflective light intensity of laser beam and light beam irradiates simultaneously, thereby realized reproducing the real-time synchro measure of light intensity and diffraction intensity.

Make tested anti-fake holographical identification do the one dimension translation, the saturating inverse ratio of establishing the branch light substrate is k, when laser beam irradiation on the sign grating, promptly during the signaling point place, the diffraction light intensity on sign to be measured surface is I _S, if the laser that this moment, laser instrument sent is I at the reflective light intensity of beam split substrate surface _R1, then inciding the surperficial laser intensity of sign through spectroscope is I ₀₁=kI _R1When the no-raster place was the noise spot place on laser beam irradiation is identifying, the diffraction light intensity on sign to be measured surface was I _N, if this moment, reflective light intensity was I _R2, the laser intensity that then incides the sign surface is I ₀₂=kI _R2Two formulas can calculate the signal to noise ratio snr and the diffraction efficiency of sign below using

$\mathrm{SNR}=\frac{I_S/I_{o1}}{I_N/I_{o2}}=\frac{I_S/{\mathrm{kI}}_{r1}}{I_N/{\mathrm{<figure-callout\; id="2"\; label="kI\; r"\; filenames="A200910067963E00091.png"\; state="\{\{state\}\}">kI</figure-callout>}}_r}=\frac{I_S/I_{r1}}{I_N/I_{r2}}---\left(1\right)$

$\mathrm{\&eta;}=\frac{I_s}{{\mathrm{<figure-callout\; id="1"\; label="kI\; r"\; filenames="A200910067963E00111.png"\; state="\{\{state\}\}">kI</figure-callout>}}_r}\&times;100\%---\left(2\right)$

Method for detecting anti-fake holographic product characteristic parameter provided by the invention comprises successively:

(1) light beam and the angled θ of tested anti-fake holographical identification sample normal (angle θ is about 51 °～65 °) that makes light source send shines sample surfaces through dividing light substrate; Wherein, divide the normal direction of light substrate not overlap with the beam direction that light source sends.

(2) place first photelectric receiver in a minute light substrate reflected light direction, in the corresponding moment of the second photoelectric receiver measuring diffraction light intensity, this divides light intensity signal on the light substrate reflection direction constantly the first photelectric receiver synchronizing detection, demarcates the incident optical power on anti-counterfeiting mark surface;

(3) place a concave mirror to converge the diffraction intensity that incides holographic anti-counterfeiting label surface light intensity in the normal direction of sample stage; Wherein, the normal direction of concave mirror does not overlap with anti-counterfeiting mark normal direction to be measured.

(4) place second photelectric receiver in concave mirror reflected light direction, obtain each point diffraction light intensity signal on the direction of scanning in real time;

(5) first photelectric receivers are converted to voltage signal again after the A/D modular converter converts digital signal to the light intensity signal of the identical moment correspondence that second photelectric receiver will obtain, send into central control module (central control module is single-chip microcomputer, DSP or ARM), by central control module the data of gathering are analyzed and handled, calculate the characterisitic parameter of anti-counterfeiting mark by following formula (1) and (2): signal to noise ratio snr and diffraction efficiency

$\mathrm{SNR}=\frac{I_S/I_{o1}}{I_N/I_{o2}}=\frac{I_S/{\mathrm{kI}}_{r1}}{I_N/{\mathrm{<figure-callout\; id="2"\; label="kI\; r"\; filenames="A200910067963E00091.png"\; state="\{\{state\}\}">kI</figure-callout>}}_r}=\frac{I_S/I_{r1}}{I_N/I_{r2}}---\left(1\right)$

$\mathrm{\&eta;}=\frac{I_s}{{\mathrm{<figure-callout\; id="1"\; label="kI\; r"\; filenames="A200910067963E00111.png"\; state="\{\{state\}\}">kI</figure-callout>}}_r}\&times;100\%---\left(2\right)$

Wherein, k is for dividing the saturating inverse ratio of light substrate, I _SBe the diffraction light intensity on sign to be measured surface, I _R1Be the reflective light intensity of beam split substrate surface, I ₀₁=kI _R1For seeing through the incident light light intensity that spectroscope incides the sign surface, I _NBe the diffraction light intensity at the surperficial noise spot of sign to be measured place, I _R2The reflective light intensity on time-division light substrate surface for this reason, I ₀₂=kI _R2For inciding the incident light light intensity on sign surface;

(6) output testing result: control LCD at last and show measurement result, measurement result can deposit USB flash disk in simultaneously.

A kind of detector of realizing the above detection method, this detector comprises:

(1) light source: be used to produce incident light and edge and the angled θ of tested anti-fake holographical identification normal (angle θ is 51 °～65 °) direction irradiation sample;

(2) divide light substrate: be arranged between light source and the tested anti-fake holographical identification, adopt the branch light substrate of fixing saturating inverse ratio, be used for forming the incident light on sign surface and incident light is carried out the reflection reference light of real-time calibration, and divide the normal direction of light substrate not overlap with the incident light direction that light source sends.

(3) example platform and displacement mechanism: be used for fixing the tested anti-fake holographical identification sample of clamping and drive sample and carry out the one dimension displacement motion, realize one-dimensional scanning to sample;

(4) first photelectric receivers: be used for obtaining in real time the strength signal of reflection reference light that is used to carry out real-time calibration of branch light substrate reflected light direction, and light intensity signal is converted to voltage signal;

(5) second photelectric receivers: be used for obtaining in real time the diffraction light intensity signal of each analyzing spot on the tested anti-fake holographical identification, and light intensity signal is converted to voltage signal;

(6) first and second signal amplification modules: be used for gathering respectively voltage signal, carry out the processing and amplifying of small-signal, and send into the A/D modular converter by after the conversion of first and second photelectric receivers;

(7) A/D modular converter:, transformation result is sent into central control module to carrying out analog to digital conversion through the voltage signal behind the first and second signal amplification modules;

(8) central control module (central control module is single-chip microcomputer, DSP or ARM): be used to receive the two ways of digital signals of A/D modular converter output, extract the diffraction light signal light intensity I on sign to be measured surface wherein after treatment _SThe reflection reference light intensity signal I of the branch light substrate reflection direction of simultaneous extraction with it _R1, and the diffraction light intensity I at the surperficial noise spot of sign to be measured place _NThe reflection reference light intensity I of the branch light substrate reflection direction of simultaneous extraction with it _R2, calculate the characterisitic parameter that anti-counterfeiting holographic product identifies according to formula (1) and (2): noise is diffraction efficiency when;

(9) display module: testing result is shown in real time;

(10) USB flash disk access module: directly store testing result into USB flash disk.

Because embedded system has advantages such as kernel is little, and specificity is strong, and system simplifies, and data-handling capacity is strong, and is low in energy consumption, more and more is subjected to people's attention.The present invention realizes detecting instrument data analysis and processing based on embedded system.With the signal amplification module, analog-to-digital conversion module, central control module, display module, USB flash disk data memory module are integrated in the cover embedded system, make the total system volume little, and cost is low, and is in light weight, makes measuring process easy, quick simultaneously.

Advantage of the present invention and good effect:

The present invention proposes the identification characteristic parameter detection method that the surperficial incident optical power of a kind of sign to be measured can be calibrated automatically, and develop the embedded detecting instrument of this method of realization.This method identifies the self-alignment method of surperficial incident optical power owing to having used, thereby makes common He-Ne laser instrument can be used as the light source that the laser holographic anti counterfeiting label characterisitic parameter detects, and this greatly reduces the detection cost.Detect owing to use two cover photoelectric receiving arrangements to carry out light intensity synchronously, realized the power self-calibration of system, the accuracy of detection of system is further improved.Signal amplification, analog to digital conversion and control module are integrated in the cover embedded system, when reducing cost,, have strengthened the operability of instrument, be more convenient for promoting the use of a whole set of instrument miniaturization, easy.

[description of drawings]:

Fig. 1 measures light path principle figure;

Fig. 2 is the entire system block diagram;

Fig. 3 is a signal amplification module schematic diagram;

Fig. 4 is an analog-to-digital conversion module;

Fig. 5 is single chip control module and interface schema thereof;

Fig. 6 is the LCD display module;

Fig. 7 is the automatic displacement example platform of an one dimension mechanical construction drawing.

Among the figure, the 1st, the He-Ne laser instrument, 2 is first photelectric receivers, the 3rd, minute light substrate, the 4th, anti-fake holographical identification to be measured, the 5th, concave mirror, 6 is second photelectric receivers, the 7th, stepper motor, the 8th, leading screw, the 9th, example platform, the 10th, sample holding piece, the 11st, rotation platform, the 12nd, line slideway.

[embodiment]:

Embodiment 1: the anti-fake holographical identification characteristic parameter detection method preferred forms that power can be calibrated automatically:

Detect principle light path such as Fig. 1, laser instrument 1 is as the light source of measuring system.Divide light substrate 3 that its surperficial luminous power of laser instrument directive is divided into transmitted light and reflected light with fixing saturating inverse ratio.Place branch light substrate reflected light direction to receive reflected light first photelectric receiver 2, this reflected light carries out real-time calibration as the reference light intensity signal of system to the luminous power that incides the anti-counterfeiting mark surface.See through and divide the transmitted light of light substrate to incide anti-fake holographical identification to be measured surface with direction with the angled θ of anti-fake holographical identification sample 4 normals to be measured (θ is about 51 °～65 °), place a concave mirror 5 in the normal direction of sign to be measured, to converge the diffraction light intensity signal of sign to be measured, receive the sign diffraction light intensity signal to be measured that converges through concave mirror with second photelectric receiver 6.

Owing to used first photelectric receiver that the luminous power that incides sign to be measured surface is carried out real-time calibration, thereby realized identifying the self calibration of surperficial incident optical power.

As Fig. 1, use the branch light substrate of inverse ratio as k, establishing the laser beam irradiation intensity of reflected light that first photelectric receiver receives when sign is the signaling point place on the grating is I _R1, the light intensity that second photelectric receiver receives is I _SLaser beam irradiation no-raster place intensity of reflected light that first photelectric receiver receives when being the noise spot place on sign is I _R2, the light intensity signal that second photelectric receiver receives is I _NFormula calculates the signal to noise ratio snr and the diffraction efficiency of sign below then available

$\mathrm{SNR}=\frac{I_S/I_{o1}}{I_N/I_{o2}}=\frac{I_S/{\mathrm{kI}}_{r1}}{I_N/{\mathrm{<figure-callout\; id="2"\; label="kI\; r"\; filenames="A200910067963E00091.png"\; state="\{\{state\}\}">kI</figure-callout>}}_r}=\frac{I_S/I_{r1}}{I_N/I_{r2}}---\left(1\right)$

$\mathrm{\&eta;}=\frac{I_s}{{\mathrm{<figure-callout\; id="1"\; label="kI\; r"\; filenames="A200910067963E00111.png"\; state="\{\{state\}\}">kI</figure-callout>}}_r}\&times;100\%---\left(2\right)$

Utilize said method and formula (1), (2) that 5 editions holographic anti-counterfeiting label samples randomly drawing are measured, the signal to noise ratio snr of mensuration and diffraction efficiency result are as follows:

Sample version number	Diffraction efficiency (%)	Signal to noise ratio snr
			1	16.128	21.860
2	25.148	23.846
			3	10.545	15.411
4	15.791	19.437
			5	23.868	25.315

According to the regulation of national standard, diffraction efficiency is greater than 12%, and signal to noise ratio (S/N ratio) is the A level greater than the product of 20:1; Diffraction efficiency is greater than 8%, and signal to noise ratio (S/N ratio) is the B level greater than the product of 10:1.As can be seen, take a sample test sample room and have certain difference from last table result, the sample version number is that the diffraction efficiency and the signal to noise ratio (S/N ratio) of 3 anti-false trademark sample all is lower than other sample, though also reach qualified, belongs to B level product.In addition, the measurement result that compares diffraction efficiency and signal to noise ratio (S/N ratio), be better than the consistance of signal to noise ratio (S/N ratio) for the consistance of same sample diffraction efficiency, this is because the sign incident optical power is relatively stable, and have certain fluctuation for noise data collection, caused snr measurement result's consistance to be inferior to the consistance of diffraction efficiency.Simultaneously, also signal to noise ratio (S/N ratio) and diffraction efficiency have the relation of direct ratio as can be seen, the signal to noise ratio (S/N ratio) height, and diffraction efficiency is also high.

Embodiment 2, utilize method of the present invention to realize anti-fake holographical identification characteristic parameter: noise is the instrument measured of diffraction efficiency when.This instrument has been realized measurement to anti-fake holographical identification characteristic parameter by power self-calibration with based on the detection method of embedded system, and optimum implementation is as follows:

Example platform (structure is seen Fig. 7), photoelectric receiving arrangement, signal amplification, analog to digital conversion and the control module and demonstration and the USB flash disk access module (system chart is seen Fig. 2) that have comprised light source in this instrument, had the automatic displacement function of one dimension.It is 5% He-Ne laser instrument 1 that light source has adopted instability, wavelength 632.8nm, Output optical power 3mw; Example platform with the automatic displacement function of one dimension drives leading screw 8 by stepper motor 7 and rotates, and leading screw 8 is converted to straight-line displacement with the circular motion of stepper motor 7, makes example platform 9 and sample holding piece 10 clamping anti-false trademark samples carry out motion in one dimension; Photoelectric receiving arrangement uses two groups of photoelectric cells to finish, and light intensity signal is converted to voltage signal; (Fig. 3) carries out processing and amplifying to the two-way voltage signal with the signal amplification module; Voltage signal after the amplification is converted to digital signal through analog-to-digital conversion module (Fig. 4), sends into then among single-chip microcomputer (Fig. 5), DSP or the ARM etc. and carries out data analysis and processing; Net result shows by LCD (Fig. 6), and can directly store USB flash disk into by the USB flash disk access module.

Adopt the method, when stepper motor 7 drive samples carried out displacement, the relative launching spot of sample produced displacement.Because the incident light irradiation is on the different position of sample, so it is in the diffraction light intensity difference of sample normal direction.Second photelectric receiver obtains multiple spot diffraction light intensity signal on the direction of scanning in real time, and measure the constantly corresponding of each point diffraction light intensity at it, this divides light intensity signal on the light substrate reflection direction, the incident intensity of demarcating the anti-counterfeiting mark surface constantly the first photelectric receiver synchronizing detection.By embedded system to the voltage signal of two-way light intensity signal conversion amplify, analog to digital conversion and computing, extract signal light intensity I wherein _S, the noise light intensity I _NAnd the two corresponding reference light intensity I _R1, I _R2After, can calculate the characterisitic parameter that anti-counterfeiting holographic product identifies according to formula (1) and formula (2): noise is diffraction efficiency when.The result shows by LCD, and the testing staff also can use USB flash disk directly to store data.

Claims (5)

1, a kind of method for detecting anti-fake holographic product characteristic parameter is characterized in that this method comprises successively:

(1) light beam and the angled θ of tested anti-fake holographical identification sample normal that makes light source send shines sample surfaces through dividing light substrate; Wherein, divide the normal direction of light substrate not overlap with the beam direction that light source sends;

(2) place first photelectric receiver in a minute light substrate reflected light direction, in the corresponding moment of the second photoelectric receiver measuring diffraction light intensity, this divides light intensity signal on the light substrate reflection direction constantly the first photelectric receiver synchronizing detection, demarcates the incident optical power on anti-counterfeiting mark surface;

(3) place a concave mirror to converge the diffraction intensity that incides holographic anti-counterfeiting label surface light intensity in the normal direction of sample stage; Wherein, the normal direction of concave mirror does not overlap with the normal direction of anti-counterfeiting mark sample;

(4) place second photelectric receiver in concave mirror reflected light direction, obtain each point diffraction light intensity signal on the direction of scanning in real time;

(5) first photelectric receivers are converted to voltage signal again after the A/D modular converter converts digital signal to the light intensity signal of the identical moment correspondence that second photelectric receiver will obtain, send into central control module, by central control module the data that collect are analyzed and handled, calculate the characterisitic parameter of anti-counterfeiting mark by following formula (1) and (2): signal to noise ratio snr and diffraction efficiency

$\mathrm{SNR}=\frac{I_S/I_{o1}}{I_N/I_{o2}}=\frac{I_S/{\mathrm{kI}}_{r1}}{I_N/{\mathrm{kI}}_{r2}}=\frac{I_S/I_{r1}}{I_N/I_{r2}}---\left(1\right)$

$\mathrm{\&eta;}=\frac{I_s}{{\mathrm{kI}}_{r1}}\&times;100\%---\left(2\right)$

Wherein, k is for dividing the saturating inverse ratio of light substrate, I _SBe the diffraction light intensity on sign to be measured surface, I _R1Be the reflective light intensity of beam split substrate surface, I ₀₁=kI _R1For seeing through the incident light light intensity that spectroscope incides the sign surface, I _NBe the diffraction light intensity at the surperficial noise spot of sign to be measured place, I _R2The reflective light intensity on time-division light substrate surface for this reason, I ₀₂=kI _R2Incide the incident light light intensity on sign surface for this moment;

(6) output testing result.

2, method according to claim 1 is characterized in that light beam and tested anti-fake holographical identification sample normal angulation θ that the light source described in (1) step sends are about 51 °～65 °.

3, method according to claim 1 and 2 is characterized in that the central control module described in (5) step is single-chip microcomputer, DSP or ARM.

4, a kind of detector of realizing the described detection method of claim 1 is characterized in that this detector comprises:

(1) light source: be used to produce incident light and edge and the angled θ direction irradiation of tested anti-fake holographical identification normal sample, θ is about 51 °～65 °;

(2) divide light substrate: be arranged between light source and the tested anti-fake holographical identification, adopt the branch light substrate of fixing saturating inverse ratio, be used for forming the incident light on sign surface and incident light is carried out the reflection reference light of real-time calibration, and divide the normal direction of light substrate not overlap with the incident light direction that light source sends;

(3) example platform and displacement mechanism: be used for fixing the tested anti-fake holographical identification sample of clamping and drive sample and carry out the one dimension displacement motion, realize one-dimensional scanning to sample;

(4) first photelectric receivers: be used for obtaining in real time the strength signal of reflection reference light that is used to carry out real-time calibration of branch light substrate reflected light direction, and light intensity signal is converted to voltage signal;

(5) second photelectric receivers: be used for obtaining in real time the diffraction light intensity signal of each analyzing spot on the tested anti-fake holographical identification, and light intensity signal is converted to voltage signal;

(6) first and second signal amplification modules: be used for gathering respectively voltage signal, carry out the processing and amplifying of small-signal, and send into the A/D modular converter by after the conversion of first and second photelectric receivers;

(7) A/D modular converter:, transformation result is sent into central control module to carrying out analog to digital conversion through the voltage signal behind the first and second signal amplification modules;

(8) central control module: be used to receive the two ways of digital signals of A/D modular converter output, extract the diffraction light signal light intensity I on sign to be measured surface wherein after treatment _SThe reflection reference light intensity signal I of the branch light substrate reflection direction of simultaneous extraction with it _R1, and the diffraction light intensity I at the surperficial noise spot of sign to be measured place _NThe reflection reference light intensity I of the branch light substrate reflection direction of simultaneous extraction with it _R2, calculate the characterisitic parameter that anti-counterfeiting holographic product identifies according to formula (1) and (2): noise is diffraction efficiency when;

(9) display module: testing result is shown in real time;

(10) USB flash disk access module: directly store testing result into USB flash disk.

5, detector according to claim 4, it is characterized in that light source use Output optical power instability is 5% common He-Ne laser instrument, photoelectric receiving arrangement is finished by two groups of silicon photocells, signal amplification, analog to digital conversion, central authorities' control and USB flash disk data memory module are based on Implementation of Embedded System, and display module is realized by LCD.

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