DE102006039185A1 - Security feature with electrochromic device - Google Patents

Abstract

The invention relates to security features comprising an organic electrochromic device and the use of electrochromic devices as a security feature. Two independent measurable quantities serve to prove the authenticity of the product. The readability is possible with simple handheld readers in seconds.

Description

The The invention relates to security features that include an organic electrochromic Device include and the application of electrochromic devices as a security feature.

For the protection of products against counterfeiting (Plagiarism) are today - ever as required, scope of protection and type of use as well as the requirements to the cost structure - different used optical and electronic systems. Optical systems are mostly passive and based on special reflective Effects (holograms, UV reflection etc.)

Other Security features are known, for example, simple passive Systems such as watermarks, silver strips, holograms or the like. But there are also active systems for counterfeit protection such as for example, remotely retrievable encrypted security features based on silicon circuits. Furthermore also biometric, e.g. DNA based systems for plagiarism protection developed especially by the company Identif.

The Electronic systems for plagiarism work with complex silicon based circuits and encryption logarithms, the common decrypted after a while and therefore no longer-term Provide protection.

task The invention is therefore an optoelectronic system for protection against plagiarism to disposal to put that reliable and long-term protective effect.

object The invention is an organic electrochromic device, a characteristic reflection or absorption spectrum and / or a characteristic feature of, for example, time-dependent) having electrical measurement, in a product or in a Packaging is integrated as a safety feature. Furthermore is The invention relates to the use of an organic electrochromic Component, a characteristic reflection or absorption spectrum and / or a characteristic feature of, for example, also time-dependent having electrical measurement as a security feature.

The structure of simple organic electrochromic devices is for example from DE 10 2005 046 960.4 As is known, between at least one electrochromically active layer is sandwiched between two conductive electrode layers, the color contrast of which changes as a function of the applied voltage between the conductive layers.

Materials for electrochromic layers are from the DE 10 2005 032 081.3 known. These can be varied by simple chemical manipulations, for example by attaching various subgroups and / or by selecting suitable fillers and / or their amount, which can also show opto-electrical activity.

Previous Passive plagiarism protection systems often offer only one feature as identification for authenticity. Of the Protection based on the use of an electrochromic device on the exam two independent Characteristics, in combination a clear hardly forfeitable Provide proof of authenticity.

moreover it is very expensive to reproduce an electrochromic system.

By using electrochromic systems as security features many advantages of these systems can be exploited:
On the one hand, an electrochromic system has an extremely simple electro-optical readout of the characteristic (electro-optical) properties of the electrochromically active layer; Second, an electrochromic active layer can be easily integrated into a product or package because it can be produced with extremely small thicknesses, high mechanical flexibility and resistance to breakage; third, the cost of an electrochromic device are very low, for example, over mass production in the printing process, and finally, the coupling of the two separately and independently readable features (optical and electrical) unequaled good plagiarism.

To the For example, a simple test with a power supply can read out of 1.5 volts and a simple appearance of color change (e.g., from transparent to red) using a color table. In addition, can be the so-called electrical transient in a hand-held device as a characteristic Size together with the absorption spectrum and / or the reflective color spectrum Evaluate and identify as a unique function. Due to the low angular dependence the reflective properties is a tilt, as in the case of Handling of the reader can occur, irrelevant.

Both Features can fully automatic within a few seconds with a single handheld reader recorded and checked become.

The inexpensive Availability of mobile and / or fixed color sensors makes one easy realization possible.

The characteristic features of the electrochromic active layer can be easily determined by Va Riation of the subgroups in the production of dyes produce but also for the skilled artisan practically not without high analysis effort to identify and difficult to imitate by the complex synthesis process.

A another possibility the characteristic features of the electrochromic active layer to manipulate is by choosing the optical fillers of the electrochromic active Material.

Also This is a big one Protection against imitation is required.

The figures show two measurements for testing an electrochromically active layer: On the one hand shows 1 the color change from white to blue, which is macroscopically visible, and secondly, it can be measured by means of a wavelength measurement (graphic in the 1 ) to verify.

1 shows by means of a reflection measurement that an optical feature, for example a reflection spectrum and / or color detection of an electrochromic device, is characteristic of the material composition of the electrochromically active formulation. In addition to the reflection spectrum, however, it is also possible to use a color sensor which detects the color values of the discolored electrochromic layer within a period of a few ms, compares them with reference values and checks the authenticity via an adjustable tolerance routine.

2 shows the measurement of the electrical transient. It is done with a simple ammeter, where the current density is plotted over time. This electrical transient is characteristic of any electrochromic system.

The electrical characteristic of the electrical transient is the characteristic Characteristic of a time-dependent electrical measurement of an electrochromic device.

By the application of a voltage of, for example, 1.5 volts to the electrochromic Device for one Period of 0.1s, 0.2s, or 1s and simultaneous capture of the transient current for a few seconds over the short circuit provides one for the electrochromically active formulation characteristic temporal current course.

With These simple detection methods can be done in an independent way double check if the security feature formed from the organic electrochromic device authentic and / or genuine.

To a further embodiment let yourself the organic electrochromic device irreversible when reading or checking in one convict other state, so that can be checked whether the goods were paid and released. This could be the usual so far retail electronic security systems through simple tags be replaced.

Security feature with electrochromic Device

The The invention relates to security features that include an organic electrochromic Device include and the application of electrochromic devices as a security feature. Two independent serve measurable sizes as proof of the authenticity of the product. The readability is with simple handheld readers in seconds possible.

Claims (5)

Organic electrochromic device with at least an electrochromically active organic layer between two conductive layers, a characteristic reflection or absorption spectrum and having a characteristic feature of an electrical measurement, that in a product or in a packaging as a security feature is integrated. Organic electrochromic device according to claim 1, where the characteristic features by simple change the subgroups of the compounds or electrically and / or optically active fillers are adjustable. Organic electrochromic device according to one the claims 1 or 2, in which the characteristic features by a (hand) reader fully automatic are detectable. Organic electrochromic device according to one the preceding claims, which can be read by color sensors. Use of an organic electrochromic device, a characteristic reflection or absorption spectrum and / or a characteristic feature of a (possibly time-dependent) electrical Measurement having as a security feature.