DE102008052248A1 - Method and device for checking lens structures - Google Patents

Abstract

The invention relates to a test method and a test device for checking lens structures (14) of a lenticular grid (18) arranged on a surface of a transparent layer (17) of a data carrier (13) for producing a tilted image, comprising the steps of: - illuminating (2) a surface cutout the lens grid (18) having at least one illumination source (10) in a first angle (12) to the orthogonal (19) of the surface; - observing (3) a first image (22, 24, 26) of the illuminated surface section with at least one optical detection unit (16) at the same first angle (12); - observing (4) a second image (21, 23, 25) of the illuminated surface section with the optical detection unit (16 ') at a second angle (12') corresponding to the first angle (12) mirrored at the orthogonal (19) , and - comparing (5) the first and second images (22, 24, 26, 21, 23, 25) for differences in image brightness.

Description

The The invention relates to a test method and a test apparatus for checking lens structures one on a surface of a transparent layer of a Disk arranged lenticular for generating a Tilting image, according to the preambles of the claims 1 and 5.

It are data carriers known, for example in the form of personalization documents, such as ID cards, passports, credit cards, bank cards, cash cards and the like, which increasingly have security features, to avoid forgery of these documents. For example a paper substrate provided with a laminating film, wherein the as Plastic layer formed laminating additionally has a lenticular array to the lenticular effect obtained thereby a tilting picture and possibly also a three-dimensional spatial To get an impression. This avoids a mere photographing the underlying personalization data applied to the paper substrate and the remaining pictorial and colored embodiments of the Personalization document. As a result, such personalization documents against counterfeiting and adulteration in addition to be protected.

A method for producing such personalization documents is described in DE-PS 29 7 004 and DE 36 34 865 described. In this case, personal data are written by means of a laser beam in the already completed, laminated card. The card consists of a Karteninlett that is closed between transparent cover layers. The labeling process takes place through the transparent cover film. Thus, on the one hand, the production can be significantly simplified, inter alia, after the personalization no further manufacturing steps are required, and on the other hand, the counterfeiting and tampering security are increased because, for example, the data caused by the laser beam material destruction in a no longer changeable form available.

at appropriate choice of laser intensity can be used simultaneously the inscription of the inlay a congruent marking reached in the volume of the cover sheet to the surface become. In addition, the cover film surface have a relief structure or a lens structure, in a simple Way also manually testable. It is thus an authenticity feature thus greatly hindering any manipulation or the attempt to imitate such a card by a counterfeiting.

traditionally, The laser beams are mostly cylindrical in shape formed lens structure, which are each semi-circular in cross-section Cylinder acting on or on the surface of a such plastic layer are applied by the laser beam hit at a certain angle to thereby the tilt image effect to obtain. For this it is important that the incident Light beam of the laser is aligned so that it is within the lens structure a common focal point or focal point of the light hits in such a way that thereby a sharp typeface on the underlying substrate, such as a paper substrate, is ensured. As a result, a viewer who looking at the underlying typeface at the same angle, as the tilt image effect exploits the typeface with the necessary Sharpness, while looking at it from a other angle the incident light is not a baring collection point or Focus hits and thus is scattered. This will cause a blurred Image received.

For checking of such lens structures that are required to be tamper-proof Personalization document So far, the already treated with the laser personalization documents after the labeling of the underlying substrate by a Contemplating those in the respective angle on their quality checked by checking that the typeface is on the sharpness was checked. As a consequence, that upon finding a defective lens structure of the lens grid already a personalization of the personalization document by means the laser beam is made and thus this personalization document destroyed and a same document be re-produced got to. This reduces the throughput of a machine for manufacturing Personalization documents.

As a result, The present invention is based on the object, a method and a device for verification of lens structures of a lens grid for media to provide which a quick check during on or before the date of the application of data allows the disk.

These Task is procedurally by the features of claim 1 and device side by the features of claim 5 solved.

• – Beleuchten eines Flächenausschnittes des Linsenrasters mit mindestens einer Beleuchtungsquelle in einem zur Orthogonalen der Oberfläche ersten Winkel;
• – Beobachten eines ersten Bildes des beleuchteten Flächenausschnittes mit mindestens einer optischen Detektionseinheit in demselben ersten Winkel;
• – Beobachten eines zweiten Bildes des beleuchteten Flächenausschnitts mit der optischen Detektionseinheit in einem zweiten Winkel, der dem an der Orthogonalen gespiegelten ersten Winkel entspricht, und
• – Vergleichen des ersten und des zweiten Bildes hinsichtlich Unterschiede in der Bildhelligkeit.

The core idea of the invention is that the following steps are used in a test method for checking lens structures of a lenticular screen arranged on a surface of a transparent layer of a data carrier for producing a tilted image:

• - Illuminating a surface section of the Lin senrasters with at least one illumination source in a first angle to the orthogonal of the surface;
• Observing a first image of the illuminated surface section with at least one optical detection unit at the same first angle;
• Observing a second image of the illuminated surface patch with the optical detection unit at a second angle corresponding to the first angle mirrored at the orthogonal one, and
• Comparing the first and second images for differences in image brightness.

• – die mindestens eine Beleuchtungsquelle zum Beleuchten des Linsenraster in dem zur Orthogonalen der Oberfläche ersten Winkel,
• – die optische Detektionseinheit zum Beobachten des ersten Bildes des beleuchteten Flächenausschnittes in demselben ersten Winkel,
• – die optische Detektionseinheit zum Beobachten des zweiten Bildes des beleuchteten Flächenausschnittes in dem zweiten Winkel, der dem an der Orthogonalen gespiegelten ersten Winkel entspricht, und
• – eine Vergleichseinheit zum Vergleichen des ersten und des zweiten Bildes hinsichtlich Unterschiede in der Bildhelligkeit auf.

A test device according to the invention for the inspection of lens structures of arranged on the surface of the transparent layer of the data carrier lenticular grid for generating the tilting image has

• The at least one illumination source for illuminating the lenticular grid in the first angle to the orthogonal of the surface,
• The optical detection unit for observing the first image of the illuminated surface section at the same first angle,
• The optical detection unit for observing the second image of the illuminated area section at the second angle corresponding to the orthogonal mirrored first angle, and
• A comparison unit for comparing the first and second images with respect to differences in image brightness.

By Such a method according to the invention and by such a device according to the invention will allow without that previously according to the Prior art requires recognition of image sharpness or the sharpness of a typeface after application of that on the disk already before the application of such Typefaces and other pictorial components as well as given color components a review of the lens structures on their Error-free within the structure and on its surface can be done. Because it is based on the differences in image brightness allows the tipping image to work on it can be checked.

Provided when observing the first image from the same direction, how the lighting is done, which is a faded in state is found to have a high image brightness value in the optical detection unit, which also represent a human eye can arrive with the necessary sharp outlines finds one Bundling the incident light rays from the lighting unit within the lens structure at a common collection point and / or Focus instead and leaves the light in the same Fail direction. This causes the tilt image effect, namely that only at a certain angle the underlying typeface or picture can be seen. In hidden state on the other hand, that is, if the optical detection unit, also known as human eye may be present in a respect to the Orthogonal inverse angle is arranged, the light is allowed from the lighting unit does not arrive as a failing light at this. Much more must be an inverse state of this area unit in their Image brightness are created, so a dark surface and no bright surface, as in the displayed state, be reproduced. The bigger the difference between the dark and the light area, the more defect free is the lens structure and thus leaves a conclusion on the quality of the functioning of the lens structure and thus the tilting picture too.

in the Contrary to the previous review procedures is in the test method according to the invention there is no need to print the volume beforehand or by laser inscription with personalization data or other To have provided data. Thus, such a review even before applying the personalization data or other data on the disk or even during application respectively. This allows during media production within a machine for the production of personalization documents already a quality and / or functionality check the lens structure and thus the lens grid. Defective partial products with respect to the lens structure thus become from the further personalization document manufacturing process excluded and thus allow an unnecessary Subsequent sorting out of the completely produced Personalization document and thus a cost-effective Production of such data carriers, in particular personalization documents. Likewise, such a test method as incoming goods inspection at the entrance of plastic layers with the arranged thereon Lens structure in the form of a lenticular grid serve.

The measurement results obtained therefrom, which are measured by means of the optical detection unit, can be directly compared and evaluated with one another. It is also possible to carry out an evaluation in such a way that first a plurality of lens structures are measured in order to store the image brightness values required as reference values and then to compare this with image brightness values of new lens grids to be checked and their lens structures. Likewise or alternatively, a stored reference value for the image brightness value can serve for comparison purposes, for a sorting out of art fabric layers with defective lens structure to allow. For this purpose, the additional step of evaluating the differences in the image brightness by means of predeterminable image brightness values, which are compared with the image brightness value of the first and second image, is present. The device according to the invention has a correspondingly designed evaluation unit for this purpose.

One Another advantage of the invention is that the measurements for verification the lens structure is not underlying or at the surface arranged printing or applied by laser inscription Information will be influenced and thus an objective review the lens structure is possible.

According to one preferred embodiment, the inventive Method preferably before taking the observation steps the step of predetermining the first angle, wherein in the Tilt image a maximum brightness value of the image is obtained and the step of predetermining the second angle, wherein obtained in the tilt image, a minimum brightness value of the image will be on. It is therefore for the light, ie for the displayed state, determines at which Illumination angle The maximum brightness of the irradiated surface section can be detected. Likewise, that illumination angle becomes when the light is hidden, ie when it is hidden, where a minimum brightness value can be obtained. These too Expected brightness values serve as reference values to use with them the brightness values of the first and second observed image to compare and thus in the presence of the same or similar image brightness a Linsendefektfreiheit or at different image brightness values to detect a lens defect.

For the predetermining of the first and second angles may be a determining unit be provided in the device according to the invention.

Further advantageous embodiments will become apparent from the dependent claims.

advantages and expediencies are the following description to be taken in conjunction with the drawing. Hereby show:

1a , b is a flow chart of the method according to the invention;

2a , b, c, d in a schematic representation of a device according to the invention for carrying out the method according to the invention for the superimposed and the suppressed state;

3a , b, c detected images or observed images for the superimposed and hidden state, as obtained by the inventive method;

4 in a diagram, the course of the brightness values as a function of the illumination angles in plastic layers with different lens structures in the displayed state;

5 in a diagram, the course of the image brightness values as a function of the illumination angles at different lens structures in the hidden state;

6 in a diagram compared image brightness values of the first and second image, as in 3 shown; and

7a , b is a comparative representation of the images of a lens structure with and without defect.

In 1a , B is shown in a flow chart, the inventive method. In one step 1 Finds a predetermination of the angles at which maximum and minimum brightness values arise depending on a hidden and a faded in state.

In one step 2 the illumination of the lens grid or the lens structure takes place at the first angle. In one step 3 the brightness of the first image is observed at a first angle. step 4 shows the observation of the second image at a second angle. step 5 leads to a comparison of the measured brightness values of the first and the second image. Thereupon takes place in step 6 an evaluation of the comparison data with predeterminable brightness values instead. In one step 7 the determination takes place as to whether a lens structure is present or not.

In 2 is a schematic representation of the inventive device for performing the method according to the invention in the displayed state and in the hidden state reproduced. In this case, the state is indicated with the state in which an optical detection unit is arranged at the same angle as the one illumination unit. The hidden state, on the other hand, shows the state in which an optical detection unit is arranged in a mirrored or inverse angle with respect to an orthogonal of the surface to the angle of the illumination unit.

The under 2 B displayed hidden State differs accordingly from the under 2a shown only in the fact that the optical detection unit 16 ' at an angle 12 ' from -15 ° and not at an angle 12 of + 15 °, like the lighting unit 10 is arranged.

The lighting unit 10 emits at least one light beam 11 that with the angle 12 with respect to an orthogonal 19 perpendicular to the surface of a plastic layer 17 a volume 13 is arranged on a lens structure 14 with several semicircular and cylindrical lenses. The lens structure takes in this case, for example, a surface 18 on the surface of the plastic layer 17 one.

In the displayed state, the optical detection unit detects 16 a failed light beam in the same direction as the incident light beam and receives a first image with a high brightness value, unless the lens structure is defective. In the hidden state, however, is a failing light beam 15 in the optical detection unit 16 ' detected with low image brightness values.

In 2c is the displayed state, as in 2a shown shown. In 2d a hidden state is shown, different from the one in 2 B shown hidden state characterized differs that not the detection unit 16 ' but the lighting unit 10 at an angle 12 ' is arranged from -15 °.

In 3a . 3b and 3c are various image recordings, as they can be obtained by the device and the inventive method, reproduced. The left-hand column shows the hidden state and the right-hand column the superimposed state. A card substrate material having a plastic layer thereon 21 The environment forms an illuminated surface section, which is created by means of the illumination unit 10 with an angle, as below 2 is shown illuminated.

In 3a the two images, ie the first and the second image, are reproduced for a defect-free lens structure. In the right column is a surface section 22 reproduced with a high image brightness value. In the left column, ie for the hidden state, is the same surface section 20 represented with an opposite image brightness value, that is, a very dark area. As a result, the difference between the first picture 22 and the second picture 20 very big in its image brightness. For such a high difference in image brightness, as in 6 under 1a is reproduced, a good quality of the lens structure is determined by the evaluation.

In 3b is the surface section in the displayed state 24 and in the hidden state, the surface section 23 have been detected with image brightness values already having a smaller difference. This is a lens structure of mediocre quality. This indicates a mediocre working tilting image. This smaller difference is reflected in 6 under 1b ,

In 3c are the two surface sections 26 and 25 have been detected for the faded in and out of the state with image brightness values such that these image brightness values have virtually no difference. This slight difference is in 6 under 1c played. Such a small difference in the image brightness of the surface cutouts in the faded-in and faded-out state determined by means of the evaluation unit results in plastic layers with such lens structures being immediately excluded from the further process since it is a non-functioning lens structure and thus a non-functioning tilt image ,

In 4 In a diagram, the brightness values are shown as a function of different illumination angles. In this case, light from an illumination unit falls at different angles onto the lens structure in the inserted state and, given a functioning tilt image structure, should lead to a maximum brightness value being able to be determined at a specific angle. Advantageously, such a pre-determining step of the maximum brightness value may be performed at a certain angle prior to the actual observation steps to thereby provide reference values regarding the brightness values of the image brightness values of the first image to be detected and, referring to FIG 5 to get the second picture.

In 4 is in the displayed state, a plurality of differently formed lens structures at different illumination angles in terms of brightness has been measured. It has been found that due to the different lens structures, their brightness values as curves 30 . 31 and 32 are shown at different illumination angles their maximum brightness values 30a . 31a and 32a exhibit. Advantageously, in the lens structure to be subsequently observed, these illumination angles, at which the brightness values maximum exist, are used both for the observation and for the illumination for carrying out the method according to the invention.

In 5 are also in a graph, the brightness values on the illumination angle for a hidden state, ie for the hidden light reproduced. This means that for a non-defective lens structure, a brightness value minimum 33a . 34a and 35a must be measured at a certain illumination angle, if the optical detection unit is arranged in the mirrored to the orthogonal inverse angle, as already described above.

6 shows in a diagram compared image brightness values of the first and second image, as in FIG 3a , b and c shown. The determination of the brightness values takes place by means of the detection unit, with 0% corresponding to a dark or black area and 100% to a light or white area respectively at the first and the second angle.

In the dark bar corresponds to the image brightness values in the diagram, in the case of a displayed state, ie in a state in which the illumination and viewing angles are identical have been. The bright or white bar corresponds to those Image brightness values at different illumination and viewing angles have been obtained, ie at the hidden state in which the size of the illumination angle and the viewing angle are identical are different, however, with respect to the orthogonal Sign +/-.

A first possibility of evaluating these measurement results is that in each case a reference value for the displayed and the hidden state 36 . 37 is determined. The lens structure of the lens grid is judged to be functional if, in the displayed state, the measured value is greater than or equal to the first reference value and / or in the blanked state, the measured value is less than or equal to the second reference value 37 is. Another possibility of the evaluation is that as a reference value, a delta 38 between the displayed and the hidden state. The lens structure is then judged to be functional if a measured delta of the two measured values is greater than or equal to the reference value delta.

In 7a and 7b First and second images are reproduced with larger surface sections that have been illuminated and measured. In 7a In the right-hand column, the first image for the displayed state is shown. The left column shows the second image for the hidden state. It can be a nearly defect-free lens structure due to the high brightness differences detect.

In 7b For example, in the right-hand column for the faded-in state, the first image for a defective lens structure is shown, and in the left column, the second image in the faded-out state is also displayed for a defective lens structure. A comparison of these two in 7b reproduced images show that no evenly distributed brightness values are present within the area cutout and thus irregularities in the lens structure must be present. This in turn leads to a smaller difference in the brightness values and thus to the result that a defective lens structure must be present.

All Features disclosed in the application documents are considered to be essential to the invention as far as they are individually or in combination the prior art are new.

1

step of predetermining

2

light

3.4

Observe

5

to compare

6

Evaluate

10

lighting source

12

first angle

12 '

second angle

13

disk

14

lens structures

16.16 '

optical detection unit

17

transparent layer

18

lenticular

19

orthogonal

21 23, 25

second image

22 24, 26

first image

30-35

Image brightness values

30a, 31a, 32a

maximum brightness

33a, 34a, 35a

minimal brightness

36 37, 38

reference value

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 297004 [0003]
• - DE 3634865 [0003]

Claims (7)

Test method for the inspection of lens structures ( 14 ) one on a surface of a transparent layer ( 17 ) of a data carrier ( 13 ) arranged lenticular grid ( 18 ) for generating a tipping image, characterized by the following steps: - lighting ( 2 ) of a surface section of the lenticular grid ( 18 ) with at least one illumination source ( 10 ) in one to the orthogonal ( 19 ) of the surface first angle ( 12 ); - Observe ( 3 ) of a first image ( 22 . 24 . 26 ) of the illuminated surface section with at least one optical detection unit ( 16 ) in the same first angle ( 12 ); - Observe ( 4 ) of a second image ( 21 . 23 . 25 ) of the illuminated surface section with the optical detection unit ( 16 ' ) at a second angle ( 12 ' ) at the orthogonal ( 19 ) mirrored first angle ( 12 ) or at the first angle ( 12 ), provided that the illumination source ( 10 ) for this in the second angle ( 12 ' ), and - comparing ( 5 ) of the first and second images ( 22 . 24 . 26 ; 21 . 23 . 25 ) regarding differences in image brightness. Method according to claim 1, characterized by the step of evaluating ( 6 ) of the differences in the image brightness by means of predeterminable image brightness values ( 30 - 35 ) with the image brightness values of the first and second images ( 22 . 24 . 26 ; 21 . 23 . 25 ). Method according to claim 1 or 2, characterized by the step of predetermining ( 1 ) of the first angle ( 12 ), in which in the tilting image a maximum brightness value ( 30a . 31a . 32a ) of the image is obtained. Method according to one of the preceding claims, characterized by the step of predetermining ( 1 ) of the second angle ( 12 ' ), in which in the tilting image a minimum brightness value ( 33a . 34a . 35a ) of the image is obtained. Inspection device for the inspection of lens structures ( 14 ) one on a surface of a transparent layer ( 17 ) of a data carrier ( 13 ) arranged lenticular grid ( 18 ) for generating a tilting image, characterized by - at least one illumination source ( 10 ) for illuminating the lens grid ( 18 ) in one to the orthogonal ( 19 ) of the surface of the first angle ( 12 ' ); An optical detection unit ( 16 ) for observing a first image ( 22 . 24 . 26 ) of the illuminated surface section in the same first angle ( 12 ); The optical detection unit ( 16 ' ) for watching a second image ( 21 . 23 . 25 ) of the illuminated surface section at a second angle ( 12 ' ) at the orthogonal ( 19 ) mirrored first angle ( 12 ) or at the first angle ( 12 ), provided that the illumination source ( 10 ) for this in the second angle ( 12 ' ), and - a comparison unit for comparing the first and second images ( 22 . 24 . 26 ; 21 . 23 . 25 ) regarding differences in image brightness. Apparatus according to claim 5, characterized by an evaluation unit for evaluating the differences in the image brightness by means of predeterminable image brightness values ( 30 - 35 ) with the image brightness values of the first and second images ( 22 . 24 . 26 ; 21 . 23 . 25 ) are comparable. Apparatus according to claim 5 or 6, characterized by a determination unit for predetermining the first angle ( 12 ), in which in the tilting image a maximum brightness value ( 30a . 31a . 32a ) of the image and predetermining the second angle ( 12 ' ) in which in the tilt image a minimum brightness value ( 33a . 34a . 35a ) of the image can be generated.