CAPACITIVE INFORMATION CARRIER WITH IMPROVED DETECTION ACCURACY BY MEANS OF A VIA AND METHOD FOR THE MANUFACTURE THEREOF

Abstract

The present invention relates to a capacitive, planar information carrier wherein vias form an electrical and/or galvanic connection between sub-areas of a first electrically conductive area being part of an electrically conductive layer on one side of the information carrier and an electrically conductive pattern on the other side of the information carrier. In another aspect, the invention relates to a method for the manufacture of an information carrier.

Claims

1. A capacitive, planar information carrier (1) comprising an electrically non-conductive substrate (2), an electrically conductive pattern (6) on a back side (9) of the information carrier (1) and a first, second and third electrically conductive area (3, 4, 5) forming an electrically conductive layer (13) on a front side (8) of the information carrier (1), wherein the electrically conductive pattern (6) and the first, second and third electrically conductive area (3, 4, 5) are formed from at least one sub-area respectively characterized in that information is encoded by characteristic features of the first electrically conductive area (3), said information being copied to the electrically conductive pattern (6) by a congruent or substantially congruent arrangement of the electrically conductive pattern (6) and the first electrically conductive area (3), wherein at least one sub-area of the first electrically conductive area (3) and at least one sub-area of the electrically conductive pattern (6) are galvanically connected by at least one via (7) comprising a bore hole (10), wherein the information is detectable by a capacitive touch screen (12), if the information carrier (1) faces the touch screen (12) with its back side (9).

2. The information carrier (1) according to claim 1, wherein electrical charges are exchanged between the second electrically conductive area (4) and a conductive object that touches said second electrically conductive area (4), causing a local change in a state of charge of the electrically conductive layer (13) which is transferred from at least one sub-area of the first electrically conductive area (3) to at least one sub-area of the electrically conductive pattern (9) by means of the at least one via (7).

3. The information carrier (1) according to claim 1, wherein the characteristic features are selected from a group comprising an overall shape of the first electrically conductive area (3) and/or the electrically conductive pattern (6), the distance of the sub-areas of the first electrically conductive area (3) and/or sub-areas of the electrically conductive pattern (6) to each other, the allocation of the sub-areas within the first electrically conductive area (3) and/or the electrically conductive pattern (6) and/or the number of sub-areas forming the first electrically conductive area (3) and/or the electrically conductive pattern (6).

4. The information carrier (1) according to claim 1, wherein the bore hole (10) is formed by mechanical drilling, laser drilling, perforation and/or laser cutting.

5. The information carrier (1) according to claim 1, wherein the information carrier (1) comprises one to ten, preferably two to seven and most preferably three to five vias (7) per one sub-area of the first electrically conductive area (3) and one sub-area of the electrically conductive pattern (6).

6. The information carrier (1) according to claim 1, wherein the electrically conductive areas (3, 4, 5) and the electrically conductive pattern (6) and the vias (7) comprise materials selected out of a group metal layer, layer containing metal particles or nanoparticles, containing electrically conductive particles, in particular carbon black, graphite, graphene, ATO, electrically conductive polymer layer, in particular Pedot, PANI, polyacetylene, polypyrrole, polythiophene, pentacene or any combination of these.

7. The information carrier (1) according to claim 1, wherein the bore holes (10) have a diameter of 0.1 to 2 mm, preferably 0.1 to 1 mm and most preferably between 0.1 to 0.6 mm.

8. The information carrier (1) according to claim 1, wherein the electrically conductive areas (3, 4, 5) and the electrically conductive pattern (6) are printed by additive printing methods selected from a group comprising offset-printing, flexo-printing, gravure-printing, screen-printing and/or digital printing.

9. The information carrier (1) according to claim 1, wherein the electrically conductive areas (3, 4, 5) and the electrically conductive pattern (6) are applied by a foil transfer process, preferably by a hot stamping method and/or a cold foil transfer method.

10. The information carrier (1) according to claim 1, wherein the electrically conductive areas (3, 4, 5) and the electrically conductive pattern (6) are applied with a chemical or physical vapor deposition method or a sputtering process.

11. The information carrier (1) according to claim 1, wherein the electrically conductive areas (3, 4, 5) and the electrically conductive pattern (6) consist of the same material and the bore holes (10) are filled with an electrically conductive material.

12. The information carrier (1) according to claim 1, wherein the filling of the bore hole (10) is executed through job steps selected from a group comprising i. printing the front side (8) of the information carrier (1) and/or ii. printing the back side (9) of the information carrier (1) and/or iii. filling of the bore hole (10) by means of a dispenser with an electrically conductive material.

13. The information carrier (1) according to claim 1, wherein the electrically non-conductive substrate (2) has a thickness of 20 to 2000 μm, preferably 50 to 1000 μm and most preferably 150 to 500 μm.

14. The information carrier (1) according to claim 1, wherein the electrically non-conductive substrate (2) consists of a flat, flexible, non-conductive material, in particular paper, cardboard, plastic, wood-based material, composite, glass, ceramic, textile, leather or any combination thereof.

15. A method for the manufacture of an information carrier (1) according to claim 1, comprising the following steps a. providing an electrically non-conductive substrate (2) and b. generating a bore hole (10) in the electrically non-conductive substrate (2) by mechanical drilling, laser drilling, perforation and/or laser cutting and c. applying an electrically conductive material for the electrically conductive areas (3, 4, 5) on the front side (8) of the information carrier (1) and d. applying an electrically conductive material for the electrically conductive pattern (6) on the back side (9) of the information carrier (1), wherein at least one bore hole (10) is filled with the electrically conductive material, i. wherein the filling of the at least one bore hole (10) is executed by one or more of the steps c and/or d, wherein conductive ink is applied on the substrate (2) or ii. wherein the filling of the at least one bore hole (10) with the electrically conductive material is executed in an additional step by the use of a dispenser, if the electrically conductive areas (3, 4, 5) and the electrically conductive pattern (6) are applied by a foil transfer process or by a chemical vapor deposition method, a physical vapor deposition method and/or a sputtering process on the electrically non-conductive substrate (2).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0111] These and other objects, features and advantages of the present invention will best be appreciated when considered in view of the following detailed description of the accompanying drawings:

[0112] FIG. 1 shows a side view of a preferred information carrier according to the present invention.

[0113] FIG. 2 shows a side view of a preferred information carrier when brought in contact with a touch screen for reading out the information carrier.

[0114] FIG. 1 shows a side view of a preferred information carrier (1) according to the present invention. The information carrier (1) consists of an electrically non-conductive substrate (2) having a front side (8) and a back side (9). On the front side (8), the information carrier (1) comprises electrically conductive areas (3, 4, 5).

[0115] In the context of the present invention, these electrically conductive areas (3, 4, 5) are referred to as first (3), second (4) and third electrically conductive area (5). They correspond to the components of a touch structure known from information carriers described in the prior art. In particular, the first electrically conductive area (3) corresponds to the touch points known from the prior art. In the context of this invention, the touch points are referred to as desired electrically conductive elements as they are supposed to trigger events on a touch screen (12) and the position of the first electrically conductive area (3) detected by the touch screen (12) is supposed to correspond to the real, physical positions of the touch points on the information carrier (1). In the prior art, distortions or deviations between the positions of the touch points (3) detected by the touch screen (12) and the real, physical positions of the touch points are caused by necessary, but interfering elements.

[0116] In the context of the present invention, these necessary, but interfering elements correspond to the second (4) and third (5) electrically conductive area placed on the front side (8) of the information carrier (1). The third electrically conductive area consists of several sub-areas. In the context of the present invention, they can be referred to as conductive traces that connect the touch points (3), either among each other or to the coupling area (4). The second electrically conductive area (4) corresponds to the coupling area known from the prior art. The purpose of this coupling area is to couple in the capacitance of a human user to the electrically conductive elements of the information carrier (1). This is achieved by a human user touching the coupling area (4). The coupling area (4) and the touch points (3) are linked galvanically or electrically by the conductive traces (5).

[0117] In addition to the electrically conductive elements on the front side (8) of the information carrier (1), the information carrier (1) comprises an electrically conductive pattern on the back side (9) of the information carrier (1). This electrically conductive pattern (6) consists of several elliptical sub-areas. In a preferred embodiment of the invention, the sub-areas of the electrically conductive pattern (6) are of circular shape. It can also be preferred that the sub-areas do not have a circular shape but have the shape of flowers, clouds, doughnuts, biscuits, hearts, stars and the like. These sub-areas forming the electrically conductive pattern (6) on the back side on the information carrier (1) which is congruent or substantially congruent to the touch points (3) on the front side (8) of the information carrier (1). In the context of this invention, the term “congruent” means that the elliptical sub-areas and the touch points have the same shape, size and orientation and they are placed at the same position on the front side (8) and on the back side (9) of the information carrier (1). This congruency of the elliptical sub-areas (6) and the touch points (3) can clearly be seen from FIG. 1.

[0118] The term “substantially congruent” refers to an electrically conductive pattern which is preferably present on the back side of the information carrier according to the present invention and which consists of sub-areas which do not necessarily have an elliptical shape, but can be present as flowers, clouds, doughnuts, biscuits, hearts, stars and all shapes that may be desired for special applications. In this case, the sub-areas on the back side of the information carrier forming the electrically conductive pattern and the touch points on the front side of the information carrier are not congruent in the strictly mathematical sense of the term congruent as they may differ in shape and size. What they have in common is their geometric centers of area and a sufficiently large area where the vias can be applied on. Sub-areas and touch points which differ in shape and size have equal geometric centers of area are referred to as “substantially congruent” in the sense of the present application.

[0119] FIG. 1 also shows a via (7) which forms a galvanic connection between the touch points (3) and the elliptical sub-areas of the electrically conductive pattern (6). In FIG. 1, only one via (7) is shown. It is preferred that one touch point (3) and one elliptical sub-area (6) are galvanically connected by 1 to 10, preferably 2 to 7 and most preferably 3 to 5 vias (7). A via (7) is formed by drilling a bore hole (10) into the electrically non-conductive substrate (2). This bore hole (10) is filled with the electrically conductive material which is used to form both the electrically conductive elements (3, 4, 5) on the front side (8) of the information carrier and the electrically conductive pattern (6) on the back side (9) of the information carrier (1). It is also possible to fill the bore hole with any other electrically conductive material. By being filled with electrically conductive material, a via (7) is capable of galvanically or electrically connecting the touch points (3) and the circular sub-areas (6) with each other.

[0120] If the electrically conductive elements on the front and the back side of the information carrier are printed on the electrically non-conductive substrate, the bore hole is filled by the ink applied to the information carrier through the printing method. In case that the electrically conductive elements are applied to the substrate of the information carrier by a foil transfer method or physical or chemical vapor deposition methods or a sputtering process, it has shown to be necessary to fill the bore hole by the use of a dispenser in an additional job step.

[0121] FIG. 2 shows a side view of a preferred information carrier (1) when brought in contact with a touch screen (12) for detecting the information carrier (1). The figure shows a device (11) with a touch screen (12). Furthermore, an information carrier (1) according to the present invention is shown in FIG. 2. The information carrier (1) is brought into contact with a touch screen (12) facing the touch screen (12) with the back side (9) of the information carrier (1). This means that the detection of the information carrier (1) is realized from the back side (9) of the information carrier (1). On the front side (8) of the information carrier (1), the touch points (3), the conductive traces (5) and the coupling area (4) are placed. The touch points (3) and the coupling area (4) are linked to each other by the conductive traces (5). These electrically conductive elements (3, 4, 5) on the front side (8) of the information carrier (1) form a touch structure known from the prior art. In the prior art, these electric conductive elements (3, 4, 5) have the same distance to the touch screen (12) as they are all placed within one single layer on the front side (8) of the information carrier (1). As these elements (3, 4, 5) all have the same distance to the touch screen (12), they all have the same capacitive impact on the touch screen (12). This can be deduced from formula A (see description).

[0122] It is the object of the present invention to generate a capacitive contrast between the desired touch points (3) on the one hand and the necessary, but interfering conductive traces (5) and coupling area (4). This aim is achieved by reducing the effective distance of the touch points (3) to the touch screen (12) and thus increasing the capacitive impact of the touch points (3) on the touch screen (12) compared to the capacitive impact of the conductive traces (5) and the coupling area (4).

[0123] In the prior art, the electrically conductive elements (3, 4, 5) on the front side (8) of the information carrier (1) are detected by a touch screen (12) when a human user touches the coupling area (4) of the information carrier (1). By the user's touch of the coupling area (4), the electrically conductive elements (3, 4, 5) of the front side (8) of the information carrier (1) are set to the same capacitive potential as the human user. In the present invention, the information carrier (1) additionally comprises vias (7) which connect the touch points (3) on the front side (8) of the information carrier (1) with the elliptical sub-areas of the electrically conductive pattern (6) on the back side (9) of the information carrier (1).

[0124] As the via (7) represents a galvanic or electrical connection between the touch points (3) and the pattern (6), the capacitance of the human user is transferred to the elliptical sub-areas (6). When the information carrier (1) according to the present invention is now brought into contact with a touch screen (12) facing the touch screen (12) with the back side (9) which comprises the elliptical sub-areas of the electrically conductive pattern (6), the distance to the elliptical sub-areas (6) is close to zero and is approximated in the present invention to be 3 μm. This length of 3 μm corresponds to the thickness of the opaque ink or the varnish layer which are used to overprint the electrically conductive elements on both sides of the information carrier. As the touch points (3) and the pattern (6) are linked galvanically with each other, this marginal, effective distance can also be assumed for the touch points (3).

[0125] As the conductive traces (5) and the coupling area (4) on the front side (8) of the information carrier (1) are not galvanically connected with any electrically conductive pattern (6) on the back side (9) of the information carrier (1), they keep their real, physical distance to the touch screen (12) which is defined by the thickness of the substrate (2). As a small distance d corresponds to an increased capacitance C according to formula A, the touch points (3) have an increased capacitive impact on the touch screen (12) compared to the conductive traces (5) and the coupling area (4). This difference in capacitance is referred to as capacitive contrast in the context of the present invention.

LIST OF REFERENCE SIGNS

[0126] 1 Capacitive, planar information carrier [0127] 2 Electrically non-conductive substrate [0128] 3 First electrically conductive area, i.e. touch point [0129] 4 Second electrically conductive area, i.e. coupling area [0130] 5 Third electrically conductive area, i.e. conductive trace [0131] 6 elliptical sub-area of electrically conductive pattern [0132] 7 via [0133] 8 front side of the information carrier [0134] 9 back side of the information carrier [0135] 10 bore hole [0136] 11 device with touch screen [0137] 12 touch screen [0138] 13 electrically conductive layer