CN103528795B - The device of hidden image in on-line checkingi liquid crystal Security element - Google Patents
The device of hidden image in on-line checkingi liquid crystal Security element Download PDFInfo
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Abstract
The invention discloses the device of hidden image in a kind of on-line checkingi liquid crystal Security element, comprise arrange according to the type of liquid crystal Security element luminescence unit, camera lens and sensor unit, signal processing unit, be placed in the first polarization filter between luminescence unit and liquid crystal Security element and be placed in camera lens and the second polarization filter between sensor unit and liquid crystal Security element, wherein, luminescence unit, for emitting parallel light; Camera lens and sensor unit, for being obtained the light signal of the image be hidden in liquid crystal Security element by the second polarization filter, and be converted to electric signal by light signal; Signal processing unit, for calculating the contrast of hidden image according to electric signal, compares the contrast calculated with reference to contrast, and manufactures the technological parameter of liquid crystal Security element according to comparative result dynamic conditioning.The present invention can realize on-line checkingi to the hidden image in all kinds of liquid crystal Security element.
Description
Technical field
The present invention relates to Techniques of Optical Security field, especially, relate to the device of hidden image in a kind of on-line checkingi liquid crystal Security element.
Background technology
Liquid crystal optical anti-counterfeiting technology has broad application prospects in anti-counterfeit field, can be produced the liquid crystal Security element with hiding positive negative image two wires anti-counterfeiting characteristic by liquid crystal multidomain directional technology.General liquid crystal Security element is first coated with oriented layer on base material, the zones of different of oriented layer carried out to the exposure of different directions, and then be coated with nematic liquid crystal layer thereon, makes liquid crystal molecule carry out the arrangement of different directions by oriented layer.
Due to liquid crystal layer water white transparency, image cannot be observed by naked eyes, and when being observed by polaroid, liquid crystal Security element presents the different region of light and shade, dark area and bright areas composition diagram picture and background respectively, polaroid is changed the rotation direction of certain angle or change circular polarizing disk, light and shade region is changed mutually, i.e. image area and background area inverse, thus the effect forming the conversion of positive negative film.
In the continuous prodution process of liquid crystal Security element, the orientation quality of liquid crystal layer and state of cure not only directly have influence on readability and the quality of hidden image in liquid crystal Security element, and can have an impact to the molecular orientation of follow-up coating, therefore, control just to seem particularly important to the quality of hidden image in process of production.
But; there is no the record about liquid crystal Security element hidden image quality on-line checkingi at present; to detect the quality of hidden image in Security element; need to sample product; this detection mode only just can be carried out under stopped status; in order to ensure the continuity of producing, cannot sample in the middle of the production run of entire volume element, being therefore difficult to the stability ensureing product quality in large production.
Summary of the invention
The technical matters that the present invention will solve is to provide the device of hidden image in a kind of on-line checkingi liquid crystal Security element, effectively can ensure the quality of hidden image in liquid crystal Security element.
According to an aspect of the present invention, propose the device of hidden image in a kind of on-line checkingi liquid crystal Security element, comprise arrange according to the type of liquid crystal Security element luminescence unit, camera lens and sensor unit, signal processing unit, be placed in the first polarization filter between luminescence unit and liquid crystal Security element and be placed in camera lens and the second polarization filter between sensor unit and liquid crystal Security element, wherein, luminescence unit, for emitting parallel light; Camera lens and sensor unit, for being obtained the light signal of the image be hidden in liquid crystal Security element by the second polarization filter, and be converted to electric signal by light signal; Signal processing unit, for calculating the contrast of hidden image according to electric signal, compares the contrast calculated with reference to contrast, and manufactures the technological parameter of liquid crystal Security element according to comparative result dynamic conditioning.
The device of hidden image in on-line checkingi liquid crystal Security element provided by the invention, real-time examination and analysb can be carried out to the hidden image in liquid crystal Security element in continuous prodution process, manufacture the technological parameter of liquid crystal Security element with dynamic conditioning, and then ensure the quality of this element.
Accompanying drawing explanation
Accompanying drawing described herein is used to provide a further understanding of the present invention, forms a application's part.In the accompanying drawings:
Fig. 1 a is the structural representation of an embodiment of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
Fig. 1 b is the structural representation of another embodiment of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
Fig. 2 is that the present invention utilizes polarization filter to observe the schematic diagram of transmission-type liquid crystal Security element.
Fig. 3 is that the present invention utilizes polarization filter to observe the schematic diagram of reflective liquid crystal Security element.
Fig. 4 a is the structural representation of the another embodiment of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
Fig. 4 b is the structural representation of an embodiment again of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
Embodiment
With reference to the accompanying drawings the present invention is described more fully, exemplary embodiment of the present invention is wherein described.Exemplary embodiment of the present invention and explanation thereof for explaining the present invention, but do not form inappropriate limitation of the present invention.
Illustrative to the description only actually of at least one exemplary embodiment below, never as any restriction to the present invention and application or use.
In the process of liquid crystal Security element, by carrying out the exposure of different directions to the zones of different of photosensitive oriented layer, the liquid crystal layer on it is made to produce different molecular orientation in zones of different, in conjunction with the accurate control to thickness of liquid crystal layer, polarized light can be made by there is different deflection conversion after the zones of different of liquid crystal layer, namely there is different polarization states.Use have suitable filter folk prescription to polarization filter observe liquid crystal Security element time, only have the light of some polarization state through polarization filter, thus to make liquid crystal Security element present the different region of light and shade, and then observe hidden image.
Fig. 1 a is the structural representation of an embodiment of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
Fig. 1 b is the structural representation of another embodiment of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
As seen in figure la and lb, device 10 in embodiment comprise arrange according to the type of liquid crystal Security element luminescence unit 102, camera lens and sensor unit 104, signal processing unit 106, be placed in the first polarization filter 108 between luminescence unit 102 and liquid crystal Security element and be placed in camera lens and the second polarization filter 110 between sensor unit 104 and liquid crystal Security element, wherein
Luminescence unit 102, for emitting parallel light, this unit can send the light of different-waveband, because liquid crystal layer is relevant with the wavelength of the thickness of liquid crystal layer and polarized light to the effect of polarized light, therefore suitable wave band can be selected according to the thickness of liquid crystal layer in liquid crystal Security element, to ensure can capture hidden image clearly at the permissible error scope inner lens of liquid crystal layer coating thickness, obtain maximum-contrast;
Camera lens and sensor unit 104, for being obtained the light signal of the image be hidden in liquid crystal Security element by the second polarization filter 110, and be converted to electric signal by light signal;
Signal processing unit 106, for calculating the contrast of hidden image according to electric signal, the contrast calculated is compared with reference to contrast, and the technological parameter of liquid crystal Security element is manufactured according to comparative result dynamic conditioning, wherein, technological parameter can comprise the exposure intensity to oriented layer and the coating speed to oriented layer.Particularly, the contrast of prior art computed image can be utilized, if the contrast calculated is less than with reference to contrast, the coating speed then suitably increasing first time exposure intensity (exposure to certain region) and/or reduce oriented layer, and/or reduce second time exposure intensity (exposure to another region), if the contrast calculated is more than or equal to reference to contrast, then illustrates that hidden image is up-to-standard, do not adjust.
Wherein, the type of liquid crystal Security element can include but not limited to transmission-type liquid crystal Security element, reflective liquid crystal Security element and hidden image+light modification liquid crystal Security element.According to the design feature of concrete liquid crystal Security element, adjustment is carried out to the wavelength of the directional light that the type of polarization filter and luminescence unit are launched and can realize on-line checkingi to the hidden image in the liquid crystal Security element of any type.
The position relationship of luminescence unit 102 and camera lens and sensor unit 104 depends on the type of liquid crystal Security element.
As shown in Figure 1a, liquid crystal Security element be transmission-type liquid crystal Security element or hidden image+light modification liquid crystal Security element time, luminescence unit 102 and camera lens and sensor unit 104 are arranged on the both sides of liquid crystal Security element along transmitted light path.Namely, luminescence unit 102 and camera lens and sensor unit 104 are placed in the both sides of liquid crystal Security element respectively, clip the transfer path relative configuration of liquid crystal Security element, the incident angle of luminescence unit 102 emitted light on liquid crystal Security element surface (namely, the angle of incident ray and liquid crystal Security element vertical plane) be no more than 10 °, camera lens and sensor unit 104 are placed in the light path of transmitted ray.
As shown in Figure 1 b, when liquid crystal Security element is reflective liquid crystal Security element, luminescence unit 102 and camera lens and sensor unit 104 are arranged on the homonymy of liquid crystal Security element along reflected light path, the light that luminescence unit 102 sends is no more than 10 ° in the incident angle on liquid crystal Security element surface, and camera lens and sensor unit 104 are placed in the light path of reflection ray.
The light that luminescence unit in this embodiment sends is after polarization filter, surperficial with certain polarization state directive liquid crystal Security element.Because the zones of different of liquid crystal layer is different to the deflecting action of polarized light, transmission or the reflection ray of liquid crystal Security element zones of different are just provided with different polarization states, again by filter after the polarization filter before camera lens and sensor unit some region through polarized light, namely the hidden image on liquid crystal Security element is captured by comparison of light and shade, obtained hidden image signal is delivered to signal processing unit and stores by sensor, and by Computerized image processing system picture quality analyzed and feed back, thus can under the prerequisite ensureing continuous production to liquid crystal Security element in the quality of hidden image effectively monitor.
Next, Rotating fields and the Observation principle of various liquid crystal Security element is simply introduced.
Fig. 2 is that the present invention utilizes polarization filter to observe the schematic diagram of transmission-type liquid crystal Security element.
As shown in Figure 2, this transmission-type liquid crystal Security element comprises transparent base 204, photosensitive oriented layer 206 and nematic liquid crystal layer 208.The thickness of nematic liquid crystal layer 208 meets λ/2 wave plate, and the liquid crystal molecular orientation angle of its zones of different is 45 degree.When detecting, incident light source and camera lens lay respectively at the both sides of liquid crystal Security element.When observing hidden image, incident parallel light is by changing linearly polarized photon into after the first polarization filter 202, the liquid crystal molecular orientation direction in its linear polarization and element region is parallel, incide in transparent base, this polarized light successively transmitted through photosensitive oriented layer 206 and nematic liquid crystal layer 208, more just can observe the hidden image produced by photosensitive oriented layer 206 and nematic liquid crystal layer 208 acting in conjunction by the second polarization filter 210.
In fig. 2, be placed in liquid crystal Security element both sides, be linear polarization filter for the first polarization filter and the second polarization filter observing hidden image.When the first polarization filter and the second polarization filter are linear polarization filter, first polarization filter and the second polarization filter are in rotatable state, to regulate the angle between the first polarization filter and the second polarization filter, such as, the saturating folk prescription of the first polarization filter can be made to parallel with the liquid crystal molecular orientation direction in one of them region (polarized light does not change through this rear polarizer direction, region), and be 45 degree of angles (polarized light turn 90 degrees partially through this rear polarizer direction, region) with the liquid crystal molecular orientation direction in another region, second polarization filter is parallel with the first polarization filter or vertically arrange, then only from element region through light can through the second polarization filter, in another region through light not by, thus make monitor staff in process of production in real time solution to the coating situation to hidden image in liquid crystal Security element.
Fig. 3 is that the present invention utilizes polarization filter to observe the schematic diagram of reflective liquid crystal Security element.
As shown in Figure 3, this reflective liquid crystal Security element comprises reflective substrate 302, photosensitive oriented layer 304 and nematic liquid crystal layer 306.The thickness of nematic liquid crystal layer 306 meets λ/4 wave plate, and the liquid crystal molecular orientation angle of its zones of different is 45 degree.Because base material is opaque specular reflective material, when detection, incident light source and camera lens are positioned at the same side of liquid crystal Security element.When observing hidden image, incident parallel light is by becoming linearly polarized light after polarization filter 308, rotatory polarization filter 308 make incident light linear polarization and the liquid crystal molecules parallel in element region (region one), then incident light and another region (region two) interior liquid crystal molecular orientation direction are 45 degree of angles, incident light is through nematic liquid crystal layer 306, its polarization state of the light of penetrating region one is constant, this polarized light penetrates photosensitive oriented layer 304 and reaches reflective substrate 302, again successively through photosensitive oriented layer 304 and nematic liquid crystal layer 306 after base material 302 reflects, its polarization state does not change always, again can pass through polarization filter 308, and its polarization state of incident light through region two changes, left-hand polarization state or dextropolarization state is changed into by linear polarization state, this polarized light penetrates photosensitive oriented layer 304 and reaches reflective substrate 302, after base material 302 reflect polarized light, change left-hand polarization light into right-handed polarized light again, right-handed polarized light is changed into left-hand polarization light, make it successively through after photosensitive oriented layer 304 and nematic liquid crystal layer 306, linear polarization state is changed into again by left/right rotatory polarization state, the linear polarization of this polarized light has deflected 90 degree compared with polarization direction during initial incidence, again can not pass through polarization filter 308.So just can observe the hidden image produced by photosensitive oriented layer 304 and nematic liquid crystal layer 306 acting in conjunction.In figure 3, for observing the polarization filter of hidden image in reflective liquid crystal Security element be linear polarization filter.
About hidden image+light modification liquid crystal Security element, it is also coated with one deck cholesteric liquid crystal layer on nematic liquid crystal layer, be compounded with angle variable color and the element hiding positive negative film feature, its structure and reflective liquid crystal Security element similar, difference is the reflection horizon of reflective type element is common metallic mirror surface coating, and use cholesteric liquid crystal layer as reflection horizon here, and in hidden image+light modification liquid crystal Security element, the liquid crystal molecular orientation angle of nematic liquid crystal layer zones of different is 90 degree.Cholesteric liquid crystal is a kind of chiral nematic phase liquid crystal with special nature, chiral material in liquid crystal phase makes liquid crystal layer produce helical structure, optionally can reflect the chirality circularly polarized light of specific wavelength (λ), namely, cholesteric liquid crystal layer only reflects the circularly polarized light of the specific rotation direction of a certain specific wavelength, the light of this another rotation direction of wavelength and the light of other wavelength through cholesteric liquid crystal layer transmissive, and absorb by other materials.Through the circularly polarized light of cholesteric liquid crystal layer reflection, polarisation of light state is constant, that is, left-hand polarization light is still left-hand polarization light after reflection, and right-handed polarized light is still right-handed polarized light.
The thickness of the nematic liquid crystal layer in hidden image+light modification liquid crystal Security element meets λ/4 wave plate, and the liquid crystal molecular orientation angle of its zones of different is 90 degree.Because cholesteric liquid crystal layer only provides the effect with angle variable color as reflection horizon, do not participate in the realization of hidden image, so the present invention carried out the detection of hidden image before coating cholesteric liquid crystal layer, when detection, incident light source and camera lens lay respectively at the both sides of liquid crystal Security element.Incident ray becomes unidirectional linearly polarized photon by linear polarization filter, and the liquid crystal molecular orientation in its polarization direction and two regions is 45 degree of angles.Light (is once-through by nematic liquid crystal layer here, no longer come and go to pass through as reflective liquid crystal Security element), Left-hand circular polarization state is changed into by linear polarization state by the polarized light in one of them region, right-hand circular polarization state is then become by another region, at this moment before camera lens, install the light that a left-handed or right-hand circular polarization filter can filter one of them region additional, realize the effect of comparison of light and shade.
In the above-described embodiments, if nematic liquid crystal layer uses as quarter-wave plate, then the wavelength X of the polarized light of detection of concealed image and the pass of thickness of liquid crystal layer are λ=4 Δ nd/ (2m+1), when the polarization direction of incident ray polarized light and liquid crystal molecular orientation are 45 degree of angles, after the nematic liquid crystal layer of λ/4 wave plate, the light of linear polarization state will change the light of Left-hand circular polarization state or right-hand circular polarization state into, if nematic liquid crystal layer uses as 1/2nd wave plates, then the wavelength X of the polarized light of detection of concealed image and the pass of thickness of liquid crystal layer are λ=2 Δ nd/ (2m+1), when the polarization direction of incident ray polarized light and liquid crystal molecular orientation are 45 degree of angles, after the nematic liquid crystal layer of λ/2 wave plate, the light of linear polarization state keeps linearly constant, but 90-degree rotation, wherein Δ n is the birefraction of liquid crystal layer, d is the thickness of nematic liquid crystal layer, m is any nonnegative integer.
Fig. 4 a is the structural representation of the another embodiment of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
Fig. 4 b is the structural representation of an embodiment again of the device of hidden image in on-line checkingi liquid crystal Security element of the present invention.
As shown in Figs. 4a and 4b, compared with the embodiment of two in Fig. 1, device 40 in these two embodiments can also comprise feedback control unit 402, be coupled with signal processing unit 106, for according to process parameter control to the exposure intensity of oriented layer in liquid crystal Security element and the coating speed to oriented layer, until meet the requirement with reference to contrast, to guarantee the quality of hidden image.
Alternatively, this device can also comprise image-display units 404, for presenting hidden image according to electric signal.This image-display units can be any equipment with display screen, and by this display window, monitor staff can understand the quality of liquid crystal Security element the very first time.
Next, describe for above-mentioned three kinds of liquid crystal Security elements the on-line checkingi how realized hidden image in detail.
(1) device of hidden image in on-line checkingi transmission-type liquid crystal Security element
Again see Fig. 4 a, luminescence unit 102 and camera lens and sensor 104 lay respectively at the both sides of liquid crystal Security element, and the transport path clipping liquid crystal Security element relatively configures, and camera lens and sensor unit 104 are placed in the light path of transmitted ray.Luminescence unit 102 emitted light is no more than 10 ° in the incident angle on liquid crystal Security element surface, the light-emitting area of luminescence unit 102 is parallel with liquid crystal Security element, send the directional light of wavelength X in 2 Δ nd/ (2m+1) ± 5 nanometer range, wherein, Δ n is the birefraction of nematic liquid crystal layer, d is the thickness of nematic liquid crystal layer, and m is any nonnegative integer.Luminescence unit 102 installs linear polarization filter 108 additional towards the one side of liquid crystal Security element, by rotate saturating folk prescription that linear polarization filter 108 changes linear polarization filter 108 to, to make its saturating folk prescription parallel to arbitrary secondary molecular orientation direction in double expose with liquid crystal Security element.Obtained light signal for obtaining the light signal of hidden image, and is converted to electric signal transmission to image display 404 and signal processing unit 106 by camera lens and sensor unit 104.Install linear polarization filter 110 additional before camera lens and sensor unit 104, rotate linear polarization filter 110 and make its saturating folk prescription to the saturating folk prescription with linear polarization filter 108 to orthogonal.
Again see Fig. 2, the hidden image liquid crystal layer of transmission-type liquid crystal element can be divided into two class regions, the saturating folk prescription of the liquid crystal molecular orientation in region one and linear polarization filter 108 is to parallel, and the saturating folk prescription of liquid crystal molecular orientation in region two and linear polarization filter 108 is in 45 ° of angles.
The light that luminescence unit 102 in Fig. 4 a sends is after polarization filter 108, through liquid crystal Security element, the polarization of light direction of penetrating region one is constant, still with the saturating folk prescription of linear polarization filter 108 to parallel, namely with the saturating folk prescription of linear polarization filter 110 to vertical, cannot through linear polarization filter 110, and the polarization of light direction of penetrating region two deflects 90 °, become with the saturating folk prescription of linear polarization filter 110 to parallel, thus can through linear polarization filter 110, thus element be made to present the different region of light and shade.When being respectively two regions and exposing, the angle in two regions may not exclusively equal 45 degree, such as, it is 42 degree, now can among a small circle dynamic conditioning linear polarization filter 110 saturating folk prescription to, make obtained hidden image have most high-contrast, in like manner also go for the following detection to reflection-type and hidden image+light modification liquid crystal Security element.Imageing sensor 104 can get the light signal of hidden image, and this light signal is converted to electrical signal transfer to signal processing unit 106 and carries out analyzing, feeding back, and on image display 404, show the hidden image obtained.
(2) device of hidden image in on-line checkingi reflective liquid crystal Security element
Again see Fig. 4 b, luminescence unit 102 and camera lens and sensor unit 104 are placed in the same side of liquid crystal Security element, and camera lens and sensor unit 2 are placed in the light path of reflection ray.Luminescence unit 102 emitted light is no more than 10 ° in the incident angle on liquid crystal Security element surface, luminescence unit 102 sends the directional light of wavelength X in 4 Δ nd/ (2m+1) ± 5 nanometer range, wherein, Δ n is the birefraction of nematic liquid crystal layer, d is the thickness of nematic liquid crystal layer, and m is any nonnegative integer.Luminescence unit 102 installs linear polarization filter 108 additional towards the one side of liquid crystal Security element, rotates linear polarization filter 108 and makes its saturating folk prescription parallel to arbitrary secondary molecular orientation direction in double expose with liquid crystal Security element.Obtained light signal for obtaining the light signal of hidden image, and is converted to electric signal transmission to image display 404 and signal processing unit 106 by camera lens and sensor unit 104.Install linear polarization filter 110 additional before camera lens and sensor unit 104, rotate linear polarization filter 110 and make its saturating folk prescription to the saturating folk prescription with linear polarization filter 108 to orthogonal.
Again see Fig. 3, reflective liquid crystal Security element comprises the lighttight reflective substrate 302 of one deck, hidden image liquid crystal layer on reflective substrate 302 can be divided into two class regions, the saturating folk prescription of the liquid crystal molecular orientation in region one and linear polarization filter 108 is to parallel, and the saturating folk prescription of liquid crystal molecular orientation in region two and linear polarization filter 108 is in 45 ° of angles.
Again see Fig. 4 b, the light that luminescence unit 102 sends is after linear polarization filter 108, reflection horizon is arrived through liquid crystal layer, again through liquid crystal layer after reflective layer reflects, in region one, after light passes twice through liquid crystal layer, its polarization direction is constant, still with the saturating folk prescription of linear polarization filter 108 to parallel, namely with the saturating folk prescription of linear polarization filter 110 to vertical, cannot through linear polarization filter 110, and the polarization of light direction of penetrating region two deflects 90 °, become with the saturating folk prescription of linear polarization filter 110 to parallel, can through linear polarization filter 110, thus make element present the different region of light and shade.Imageing sensor 104 can get the light signal of hidden image, and this light signal is converted to electrical signal transfer to signal processing unit 106 and carries out analyzing, feeding back, and on image display 404, show the hidden image obtained.
(3) device of hidden image in on-line checkingi hidden image+light modification liquid crystal Security element
In anti-counterfeiting characteristic, hidden image+light modification liquid crystal Security element is more than transmission-type liquid crystal Security element with angle variable color light become feature.In architectural feature, hidden image+light modification liquid crystal Security element is more than transmission-type liquid crystal Security element one deck becomes the cholesteric liquid crystal layer of feature for generation of light, and also different for generation of the thickness of the nematic liquid crystal layer of hidden image.In manufacture craft, in two kinds of elements, the molecular orientation of nematic liquid crystal layer is also different.
Although hidden image+light modification liquid crystal Security element is more than transmission-type liquid crystal Security element, one deck becomes the cholesteric liquid crystal layer of feature for generation of light, and the present invention carried out the detection of hidden image before coating cholesteric liquid crystal layer, therefore, and still can see Fig. 4 a.As shown in fig. 4 a, luminescence unit 102 and camera lens and sensor unit 104 lay respectively at the both sides of liquid crystal Security element, and clip the transport path relative configuration of liquid crystal Security element, camera lens and sensor unit 104 are placed in the light path of transmitted ray.Luminescence unit 102 emitted light is no more than 10 ° in the incident angle on liquid crystal Security element surface, luminescence unit 102 sends the directional light of wavelength X in 4 Δ nd/ (2m+1) ± 5 nanometer range, wherein, Δ n is the birefraction of nematic liquid crystal layer, d is the thickness of nematic liquid crystal layer, and m is any nonnegative integer.Luminescence unit 102 installs linear polarization filter 108 additional towards the one side of liquid crystal Security element, rotate linear polarization filter 108 make its saturating folk prescription to molecular orientation double expose with liquid crystal Security element respectively in+45 ° with-45° angle.Obtained light signal for obtaining the light signal of hidden image, and is converted to electric signal transmission to image display 404 and signal processing unit 106 by camera lens and sensor unit 104.Incident ray is after nematic liquid crystal layer, and the light through liquid crystal Security element zones of different is converted to left circularly polarized light and right-circularly polarized light respectively, for observing hidden image, needs to install circular polarization filter 110 additional before camera lens and sensor unit 104.Circular polarization filter 110 can be Left-hand circular polarization filter or right-hand circular polarization filter.
The hidden image liquid crystal layer of hidden image+light modification liquid crystal Security element can be divided into two class regions, the saturating folk prescription of the liquid crystal molecular orientation in region one and linear polarization filter 108 is in+45 ° of angles, and the saturating folk prescription of liquid crystal molecular orientation in region two and linear polarization filter 108 is to being-45 ° of angles.
The light that luminescence unit 102 sends is after linear polarization filter 108, transmitted through liquid crystal Security element, through the light of liquid crystal Security element zones of different, be converted to left circularly polarized light and right-circularly polarized light respectively, the light of one of them rotation direction is only had through the circular polarization filter 110 before camera lens and sensor unit 104, thus to make element present the different region of light and shade.Camera lens and sensor unit 104 can get the light signal of hidden image, and this light signal are converted to electrical signal transfer to signal processing unit 106 and carry out analyzing, feeding back, and on image display 404, show the hidden image obtained.
In on-line checkingi liquid crystal Security element in the above embodiment of the present invention, the device of hidden image can carry out on-line checkingi continuously to the quality of hidden image in liquid crystal Security element in production run; without the need to shutting down sampling; not only ensure that the continuity of production and the integrality of liquid crystal Security element; but also can be analyzed picture quality by Computerized image processing system; in real time processing parameter is adjusted, ensure the quality of continuous prodution element.
In this instructions, each embodiment all adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, and part identical with similar between each embodiment can cross-reference.
Although be described in detail specific embodiments more of the present invention by example, it should be appreciated by those skilled in the art, above example is only to be described, instead of in order to limit the scope of the invention.It should be appreciated by those skilled in the art, can without departing from the scope and spirit of the present invention, above embodiment be modified.Scope of the present invention is limited by claims.
Claims (10)
1. the device of hidden image in an on-line checkingi liquid crystal Security element, it is characterized in that, comprise arrange according to the type of described liquid crystal Security element luminescence unit, camera lens and sensor unit, signal processing unit, be placed in the first polarization filter between described luminescence unit and described liquid crystal Security element and be placed in described camera lens and the second polarization filter between sensor unit and described liquid crystal Security element, wherein
Described luminescence unit, for emitting parallel light;
Described camera lens and sensor unit, for being obtained the light signal of the image be hidden in described liquid crystal Security element by described second polarization filter, and be converted to electric signal by described light signal;
Signal processing unit, for calculating the contrast of hidden image according to described electric signal, compares the contrast calculated with reference to contrast, and manufactures the technological parameter of described liquid crystal Security element according to comparative result dynamic conditioning.
2. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 1, it is characterized in that, described device also comprises:
Image-display units, for presenting hidden image according to described electric signal.
3. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 1, it is characterized in that, the type of described liquid crystal Security element comprises transmission-type liquid crystal Security element, reflective liquid crystal Security element and hidden image+light modification liquid crystal Security element.
4. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 3, it is characterized in that, when described liquid crystal Security element be transmission-type liquid crystal Security element or reflective liquid crystal Security element, described first polarization filter and described second polarization filter are linear polarization filter.
5. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 3, it is characterized in that, when described liquid crystal Security element is hidden image+light modification liquid crystal Security element, described first polarization filter is linear polarization filter, and described second polarization filter is circular polarization filter.
6. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 3, it is characterized in that, for described transmission-type liquid crystal Security element and described hidden image+light modification liquid crystal Security element, described luminescence unit and described camera lens and sensor unit are arranged on the both sides of described liquid crystal Security element along transmitted light path.
7. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 3, it is characterized in that, for described reflective liquid crystal Security element, described luminescence unit and described camera lens and sensor unit are arranged on the homonymy of described liquid crystal Security element along reflected light path.
8. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 4, it is characterized in that, when described first polarization filter and described second polarization filter are linear polarization filter, described first polarization filter and described second polarization filter are in rotatable state, to regulate the angle between described first polarization filter and described second polarization filter.
9. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 1, is characterized in that, also comprise:
Feedback control unit, is coupled with described signal processing unit, for according to described process parameter control to the exposure intensity of oriented layer in described liquid crystal Security element and the coating speed to described oriented layer.
10. the device of hidden image in on-line checkingi liquid crystal Security element according to claim 1, is characterized in that, the wavelength of the directional light that described luminescence unit is launched is relevant to the coating thickness of liquid crystal layer.
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| CN107065238B (en) * | 2017-01-22 | 2020-07-03 | 京东方科技集团股份有限公司 | Alignment film surface detection device and method |
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Address after: 100070 8th floor, building 2, No.5 Zhonghe Road, Fengtai Science City, Fengtai District, Beijing Patentee after: China Banknote Printing Technology Research Institute Co.,Ltd. Patentee after: China Banknote Printing and Minting Group Co.,Ltd. Address before: 100070 8th floor, building 2, No.5 Zhonghe Road, Fengtai Science City, Fengtai District, Beijing Patentee before: China Banknote Printing Technology Research Institute Co.,Ltd. Patentee before: CHINA BANKNOTE PRINTING AND MINTING Corp. |