EP2451720A1

EP2451720A1 - Electro-optically switchable system

Info

Publication number: EP2451720A1
Application number: EP10734074A
Authority: EP
Inventors: Bastian Ewald; Dirk Gerhard; Hartmut Hibst
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2009-07-07
Filing date: 2010-07-06
Publication date: 2012-05-16
Also published as: WO2011003915A1; JP2012533086A; KR20120102581A; CN102470960A; US20120106139A1

Abstract

The present invention relates to an electro-optically switchable system, which comprises an optically active element (2) and a push-button (41), to a container (3) comprising such an electro-optically switchable system, and to the use of such an electro-optically switchable system for providing containers that allow increased light to pass through into the insides thereof only for the duration of a control intervention.

Description

The present invention relates to an electro-optically switchable system comprising an optically active element and a probe, a container comprising such an electro-optically switchable system and the use of such an electro-optically switchable system for providing containers, which increases the passage of light into their interior only for the duration of an operator intervention allow.

It is known that the mechanical, chemical and / or aesthetic properties of materials often deteriorate irreversibly under the permanent action of light, optionally in combination with oxygen and / or heat. This is especially true for inanimate organic materials, which are often particularly sensitive to light. In this case, not only openly accessible, but also packaged in translucent packaging products are subject to the action of light, which can lead to damage to the mechanical, chemical, olfactory, gustatory and / or aesthetic property of these packaged products. The negative change manifests itself in different ways, depending on the packaged contents, for example in a change in the appearance, such as yellowing and discoloration, in a change in the taste and / or the odor and / or in the degradation of ingredients. For food, perfumes and cosmetic products, the shelf life can be greatly reduced. Often there are quality reductions, for example to sensory quality changes, reduced shelf life and / or vitamin losses. In addition, the action of light in combination with the

Atmospheric oxygen leads to the formation of radicals and consequently to oxidative reactions. The susceptibility to light is a very specific property of the product. Particularly susceptible constituents of the formulation (eg chlorophyll-containing ingredients such as herbs) increase the susceptibility to light, which must be taken into account in the individual case when packaging such a material.

Consumer goods and especially food are exposed to strong light in the commercial counters and can therefore suffer significant quality damage. On the other hand, the presentation of the products under an appealing counter lighting promotes the buying incentive. A transparent packaging allows for a testing customer view of the product and thus supports the impression of quality and / or freshness. Ecological aspects also promote the trend towards packaging made of transparent monomaterials. The use of at least partially transparent containers as packaging material can therefore not be waived.

From the sales area various types of packaging are known. Common packaging materials include both rigid materials such as metal or glass as well as flexible materials such as plastics, cardboard, etc. as well as all possible combinations thereof. The packages are either transparent, so that the state (color, discoloration, surface texture, size, lumpiness, fineness, etc.) of the product is as clearly visible, or - as in the case of light-prone products - from an opaque or dark-colored material. Light-opaque or dark-colored packaging that protects light-sensitive products from exposure to light has the disadvantage that the product can not be visually assessed before opening the packaging. Alternatively, packaging systems for light-sensitive consumer goods also use semi-transparent plastic packaging materials that replace traditional packaging materials such as tinplate (opaque) or glass (transparent). In this case, the light-prone product is less exposed than in fully transparent packaging, yet a light-prone product is not adequately protected from exposure to light. There is thus a need for packaging which, on the one hand, protects the packaged goods effectively against damaging effects of light and, on the other hand, permits a visual assessment of the product.

Regardless of whether a product is sensitive to light or not, an opaque packaging arouses curiosity about its contents. This is especially true for optically high-quality designed packaging for high-end consumer goods and luxury goods, such as jewelry, high-quality consumer electronics, etc. Here, a package that requires only an operator intervention of the consumer to catch a glimpse of the packaged good, a decisive argument for the Purchase the product. There is therefore also a need for packaging which is suitable for bringing about an increase in the consumer's purchasing incentive.

Optically active elements are known in the field of glasses, or glasses and window systems. The switching effect is already integrated in the glazing. One distinguishes between the following principles:

Thermochrom: coloring by temperature change,

Thermotropic: clouding due to temperature change,

Photochrom: coloring (darkening) under the influence of light,

- electrochromic: coloring by electric current, and

Photoelectrochrome: activated electrochromic circuit under the influence of light.

Photochromic glasses or plastic discs are found, for. B. in self-tinting sunglasses. When exposed to sunlight, these glasses darken, but remain transparent (ie under illumination with sunlight, the transmission goes back in the visible spectral range). This effect is generally caused by UV light or short-wave visible light, it comes z. B. to reversible transitions of glass embedded silver halides or on the plastic discs applied organic layers. Photochromic glasses can also be produced on the principle of a dye-sensitized solar cell. The photochromic glass can then be based, for example, on a multilayer system comprising a catalytic platinum layer and in each case a nanoporous WO ₃ and TiO ₂ layer, which are applied to a glass substrate. The pores contain an electrolyte with positive lithium ions and negative iodide ions. On the titanium dioxide are dye molecules, which are excited by the incident light and thereby inject electrons through the TiO ₂ into the tungsten oxide. At the same time, the lithium ions attach to the WO ₃ , and the iodide ions donate electrons to the dye molecules. Through these processes, the tungsten oxide turns blue.

Electrochromic glass uses the property of electrochromic materials to change the light transmission according to the applied DC voltage. Suitable as electrochromic mate- materials z. For example, organic and inorganic materials which have different absorption properties in different oxidation states, which can be reversibly switched electrochemically. So z. B. Polyaniline (PANI) in the reduced state colorless and green in the oxidized state, poly (o-phenylenediamine) (PPD) is colorless in the reduced state and reddish brown in the oxidized state. The glass changes color as electrical charges are delivered to a microscopically thin coating of electrochromic material on the glass surface. For electrochemical transposition of the active layer, a DC voltage in the single-digit voltage range is generally sufficient. The low current activates the electrochromic layer (about one micron thick), which changes color. Depending on the purpose, the voltage can be applied manually or automatically, for example, controlled by sensors that measure the brightness. If the glass is short-circuited or the polarity of the voltage is changed, it becomes colorless again or a color change takes place. For electrochromic materials, energy is only needed for switching. The electrochromic glass thus only requires power during the coloring phase and during the production of complete transparency (or during a color change phase). If no voltage is applied, the glass will retain its current state of coloration until power is restored. Areas of application for electrochromic materials are above all automatically dimming rearview mirrors in motor vehicles and building glazings. While photochromic systems react only passively to the lighting conditions, photoelectric systems are switchable in their transmission. The energy to discolor as in photochromic systems provides the sunlight. In photo-electrochromic layers, the mechanisms of action of an electrochromic layer and an electrochemical solar cell are combined. The charge transfer takes place via transparent, electrically conductive layers on glass substrates. The layer is switched via an external circuit: If the external circuit is open, the layer becomes colored under irradiation. If the circuit is closed, it discolors the shift again. This process takes place both in lighting and in the dark, ie the transmission can be increased again by switching both in lighting and in the dark. JP 051451852 A describes a cooling chamber for medical purposes. This has a window through which the interior is visible. The window comprises two substrate plates with liquid crystals that can be powered by transparent electrodes. By actuating an electro-mechanical button, the circuit can be closed, whereby the window, which is opaque milky white in the currentless state, becomes transparent. A disadvantage of this system is that always an operator intervention is required to change the Lichtdurchtrittseigen- properties of the window. An embodiment as a self-regulating system, eg. As a control of the light transmission in dependence on the external light conditions, is not possible. It is also always a conventional power source mandatory. This complicates, among other things, a miniaturization of the system and thus a use in packaging.

It is an object of the present invention to provide a device which is advantageously suitable for containers and especially for packaging, which at the same time protects goods against too strong a light influence and permits a visual assessment of the product. It is a further object of the present invention to provide a device suitable for containers, and especially packaging, which stimulates the consumer's desire to buy. Surprisingly, it has been found that an electro-optically switchable system which comprises a sensor based on a photovoltaic effect in combination with an optically active element is advantageously suitable for achieving this object. In this case, an optically active element is used in particular, which at least partially prevents the passage of light in the visible wavelength range in the illuminated state and which allows an increased passage of light in the visible wavelength range by switching an electrical circuit. These electro-optically switchable systems can advantageously be combined with a multitude of different packaging materials to provide novel containers which effectively protect articles therein from excessive exposure to light, permit visual evaluation of the product without the need for opening the container, and encourage consumers to buy. Specifically, a configuration is made possible as a "self-switching" system, wherein the device automatically assumes a darkened state when the amount of light impinging on them exceeds a certain limit. There is then no further intervention by an operator required, for. B. to protect the contents of a package. Even after an operator intervention which leads to an increase in the passage of light into the interior of the direction leads, z. For example, to view the contents of a package, the device automatically returns to a safe state.

A first subject of the present invention is therefore an electro-optically switchable system comprising an optically active element which at least partially prevents the passage of light in the visible wavelength range in the illuminated state and an increased passage of light in the visible by switching an electrical circuit Wavelength range, and a photovoltaic effect based on a button, which increases the passage of light for the duration of the operation of the probe, the passage of light by pressing the button can be increased substantially independent of the external illumination state of the system.

Another object of the invention is a container comprising such an electro-optically switchable system.

Another object of the invention is the use of such an electro-optically switchable system as a component of a container that allows for the duration of actuation of the probe increased light transmission into its interior.

Another object of the invention is the use of such an electro-optically switchable system as a component of a container for substances that are to be stored protected from the influence of light. Another object of the invention is the use of a container comprising such an electro-optically switchable system, as a package for the protection of products packaged therein against the damaging effect of light.

Another object of the invention is the use of a container comprising such an electro-optically switchable system, as a package to increase the Kaufanreizes in a consumer.

The electro-optically switchable system according to the invention, which comprises a sensor based on a photovoltaic effect in combination with an optically active element, has at least one of the following advantages: optimum product protection since the electro-optically switchable system can be designed so that a switching action prevents the passage of light,

- Possibility to design as a "self-switching"system; the device automatically assumes a darkened state when the amount of light impinging upon it exceeds a certain limit, when using a solar cell as a button, this can simultaneously serve as a voltage source for the optically active element; Thus, it is possible to dispense with an external voltage source as compared to conventional electromechanical buttons.

- When using a solar cell as a button, this can simultaneously serve as a sensor for the incident light, z. B. to allow an independent darkening of the device

when using a photoelectrochemical system, the same function as a combination of solar cell and optically active element can be realized in one component,

also suitable for small containers,

suitable also for containers with a curved surface,

when using suitable optically active elements, for. B. based on liquid crystals, they can simultaneously serve as a display (LCD); this allows the reproduction of optical information, eg. For product adverts or advertising messages,

effective buying incentive.

In the context of the invention, light in the visible wavelength range is understood to mean a wavelength range of 400 to 800 nm. Of course, if desired, the electro-optically switchable system according to the invention can additionally at least partially prevent the passage of light in other wavelength ranges. For this purpose, a combination with conventional stabilizers or stabilizer compositions is possible. These preferably include inorganic pigments, preferably white pigments, especially titanium dioxide. The electro-optically switchable system according to the invention may additionally comprise at least one further component selected from antioxidants, light stabilizers, metal deactivators, etc., and mixtures thereof. Suitable antioxidants, light stabilizers, metal deactivators are, for example, selected from: 4,4-diarylbutadienes, cinnamic acid esters, benzotriazoles, hydroxybenzophenones, diphenylcyanoacrylates, oxamides (oxalic acid diamides), 2-phenyl-1,3,5-triazines, antioxidants, nickel compounds, sterically hindered Amines (HALS), metal deactivators, phosphites and phosphonites, hydroxylamines, nitrenes, amine oxides, benzofuranones, indolinones, thiosynergists, peroxide-destroying compounds and mixtures thereof. Suitable stabilizers and stabilizer compositions are commercially available, e.g. B. under the name Uvinul ® from BASF SE.

In the context of the present invention, "electro-optically switchable" means that the transmission with respect to light in the visible wavelength range can be changed by means of a switching operation. The switching process combines electrical (on) and optical effects, for example by converting light into electrical energy. In the context of the present invention, an optically active element is understood to mean a sheet-like component which has at least two states: one with high light transmission and one with low light transmission. Suitable elements are those which have at least one optically active material. The term optically active material refers to a material that can be converted reversibly from one of a state of high light transmission in a state of low light transmittance. In a suitable embodiment, the optically active element has a layered structure, wherein at least one of the layers has at least one optically active material. The element may also comprise two or more than two different optically active materials in one layer, the same optically active material in two or more than two separate layers, two or more than two distinct optically active materials in either one of two or more have more than two separate layers arranged.

An optically active element according to the invention is changeable in its transparency. The term "translucency" is not limited to the "translucency" in the context of the invention and is not intended as a definition of "transparency" (in the sense of transparency = image or Blickdurchlässigkeit). Accordingly, according to the invention, the change in light transmittance can be achieved by coloration / discoloration or turbidity / cancellation of turbidity.

By pressing / not pressing the button, the light transmittance of the optically active element is increased / decreased. This does not necessarily mean that the optically active element has complete transparency when the button is actuated, but also includes states in which turbidity or coloration prevents a portion of the visible light from passing through. Likewise, the optically active element does not necessarily completely prevent the passage of visible light when the pushbutton is not actuated. If the button is not pressed, only a greater amount of visible light is prevented from passing through clouding or coloring than when the button is pressed.

In a first preferred variant of the electro-optically switchable system, the optically active element at least partially prevents the passage of light in the visible wavelength range when the voltage is present and allows an increased passage of light in the visible wavelength range by interrupting the electrical circuit. In a second preferred variant of the electro-optically switchable system, the optically active element at least partially prevents the passage of light in the visible wavelength range at non-applied voltage and allows by the closing of the electric circuit increased passage of light in the visible wavelength range.

In the context of the invention, an illuminated state is understood to mean that light strikes the optically active element in the visible wavelength range. By increasing the passage of light is meant an increase in the transmission of the transmitted light in the visible wavelength range. The transmission is preferably increased by at least 5%, particularly preferably at least 10%, in particular at least 15%, especially at least 20%, especially at least 25%, by actuating the pushbutton.

The optically active element in the illuminated state when the pushbutton is not operated preferably has a transmission of at most 50%, particularly preferably not more than 40% and in particular not more than 20%, based on the light from the outside falling on the optically active element of the entire visible wavelength range , on.

The optically active element preferably has a transmission of at least 60%, more preferably of at least 70% and in particular of at least 80%, based on the light falling on the optically active element from the outside of the entire visible wavelength range in the illuminated state upon actuation of the probe on.

The switching of the electrical circuit may be, for example, a closing or interrupting the circuit.

A button is understood to mean a control element which is actuated by pressure or approach and then returns to the starting position. Unlike the switch, which remains in the respective position, one can not recognize on the pushbutton itself whether it has been actuated; this is only recognizable from the effect that has been triggered. A button has only the two possible switching states "on" and "off".

A switch based on a photovoltaic effect is a switch whose switching state depends on the light intensity received by it. In this case, there is a limit value for the recorded light intensity, also referred to as a threshold value, below which the switching state is "off" and when it is reached or above which the switching state is "on". "Substantially independent of the external illumination state" means that the intensity of the light incident on the optically active element from the outside generally does not play a role. Only when the intensity of the light falling from outside onto the optically active element falls below the threshold value of the probe is the transmission of the optically active element switched without the intervention of an operator. However, this is generally not critical, since the amount of light passing through the optical element in this case is only very small. Thus, z. For example, in the case of use of the electro-optically switchable system in a packaging for materials which are to be protected from exposure to light, damage in general can be ruled out.

In a preferred embodiment of the electro-optically switchable system according to the invention, the probe comprises a solar cell or consists of a solar cell. A solar cell or photovoltaic cell is an electrical component that converts the radiant energy contained in the light directly into electrical energy.

If the solar cell is darkened below a threshold value, power generation is interrupted. The solar cell thus assumes the function of a button, since a circuit is desired depending on the light intensity. In the present case, the solar cell is switched so that it no longer emits electricity below a predetermined limit value or threshold value for the incident light quantity or intensity. This threshold is chosen so that a slight reduction of the incident light quantity or intensity, eg. B. falling on the solar cell shadow, not sufficient to interrupt the flow of electricity. Only with the targeted darkening of the cell, for example by a thumb, a hand or an object, the current flow is interrupted. Thus, the light transmittance of the optically active element is controlled by an arbitrary intervention.

According to the first variant of the electro-optically switchable system according to the invention described above, the optically active element prevents the passage of light in the visible wavelength range at least partially and allows by the interruption of the electrical circuit increased passage of light in the visible wavelength range.

If, in this connection, the circuit is closed when the light is incident, the light transmittance of the optically active element is reduced, as a result of which the optically active element is colored. By pressing the button (eg darkening a solar cell below a threshold value), the circuit is interrupted and the light transmittance of the optically active element is - substantially independent of the external illumination state - increased. The switching states according to this first variant can be summarized as follows:

In a special embodiment of the first variant, the probe comprises a solar cell or consists of a solar cell. This embodiment makes it possible to provide an electro-optically switchable system according to the invention which, in addition to the solar cell, has no further current source. Thus, it is possible to dispense with at least one component compared to conventional systems based on an electro-mechanical probe. Furthermore, the use of a solar cell allows the design as a "self-switching" system, d. H. The device automatically assumes a darkened state when the amount of light impinging on it exceeds a certain limit. In a completely dark environment below a fixed threshold, the circuit is broken and the light transmittance of the optically active element is increased.

The switching states according to the first variant when using a solar cell can be summarized as follows:

In a preferred embodiment of the electro-optically switchable system according to the invention, the optically active element comprises liquid crystals. Preferably, the optically active element comprises at least two liquid-crystalline layers which have the same chirality and which absorb in a similar wavelength range. Particularly preferably, the optically active element comprises at least two chiral nematic layers which have the same chirality and which absorb in a similar wavelength range.

In principle, liquid crystals and interconnections, as used in known LCDs (liquid crystal displays), are suitable. These include devices based on simple liquid crystal cells, eg. B. according to the principle of Schadt-Helfrich cell. These are nematic cells (twisted nematic, TN), the two conductive comprise transparent substrates, between which the liquid crystals are located. The preferred directions of the two substrate plates are rotated by 90 ° from each other. Also suitable are devices based on STN (super twisted nematic) cells. Here, the twist angle is in a range of 180 to 270 °. Also suitable are devices based on cholesteric LCDs.

The electro-optically switchable system according to the invention can be produced analogously to conventional LCDs which are based on inflexible substrates. These systems are particularly suitable for use in containers having at least one flat surface. The electro-optically switchable system according to the invention can furthermore be produced analogously to LCDs which are based on flexible substrates. This is a preferred embodiment of the invention. Electro-optical systems based on liquid crystals on flexible substrates are suitable for use in a large number of different containers and in particular packaging, such as cardboard boxes, bottles, cans, bags, bags, etc.

Suitable substrates for organic solar cells are z. Oxidic materials (such as glass, ceramics, SiO 2, quartz, etc.), polymers (eg, polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, polyesters, fluoropolymers, polyamides, polyurethanes, polyalkyl (meth) acrylates, polystyrene, polyvinyl chloride and mixtures and composites thereof) and combinations thereof.

Preferably, a material at least partially transparent to the incident light is used as the electrode material for the substrate facing the viewer. These include, in particular, glass and transparent polymers, such as polyethylene terephthalate. The electrical contacting is usually carried out by metal layers and / or transparent conductive oxides (TCOs). These include preferably ITO, doped ITO, FOB (fluorine doped tin oxide), AZO (aluminum doped tin oxide), ZnO, TiO 2, Ag, Au, Pt.

For the preparation of electro-optically switchable systems wherein the optically active element comprises liquid crystals, reference is made in its entirety to the disclosure of the following documents: You-Jin Lee et al. describe in Mol. Cryst. Liq. Cryst, Vol. 480, pp. 278-283 (2008), discloses the preparation of mechanically stable flexible LC polymer LC blend by phase separation, resulting in so-called pixel-isolated LCs (PILC) (see also Se-Jin Jang et al., Jpn. J. Appl. Phys., Vol. 44, No. 9A (2005), pp. 6670-6673). Y.-T. Kim et al. describe in Appl. Phys. Lett. 88, 263501 (2006), pixel-encapsulated flexible displays based on a multifunctional elastomer substrate for self-orienting LCs. Mol. Cryst. Liq. Cryst, Vol. 470, pp. 191-197 (2007), describes stable flexible LCDs through the use of microstructures that serve as spacers between the substrates.

Se-Jin Jang et al. describe in SID International Symposium 2007, Digest of Technical Papers, Vol. XXXVIII, Book I, pp. 653-656, the tight bond between two plastic substrates for making flexible LCDs.

Y. Watanabe et al. describe in SID International Symposium 2007, Digest of Technical Papers, Vol. XXXVII, Book I, p. 418-419, transparent plastic films with excellent optical properties for flexible LCD.

Y.-T. Kim et al. describe in 2006 IEEE Leo's Annual Meeting Conference proceedings, Montreal, QC, Canada, pp. 424-425, highly flexible LCDs with plastic substrates for mobile applications.

T. Schneider et al. Describe in Proc. of SPIE Vol. 6487, 64870J, (2007), flexible cholesteric LCDs.

In a further preferred embodiment of the electro-optically switchable system according to the invention, the optically active element comprises polymer-dispersed liquid crystals (PDLC). Polymer-dispersed liquid crystals generally require a voltage in the range of about 10 to 20 V when switching. Advantageously, they are distinguished by their ease of manufacture. They are particularly suitable for use in permanently installed devices, eg. For example, sales counters and presentation showcases. The production of PDLCs is z. By T. Kajiyama et al. in the Annual Report of the Faculty of Engineering, Kyush (2003), "Development of Flexible and Large-area Liquid Crystal Display Devices", pp. 19-28. In a polymer dispersed liquid crystal (PDLC) element, it is possible to change the transparency of the element by applying an electrical voltage. The functional principle of a PDLC element is based on an optically active material consisting of tiny liquid crystal droplets scattered within a solid polymeric material. This material, also known as LC-FiIm, is located between two conductive coated plastic films. These lie within a laminated or foil composite and ensure the flow of current. Without electrical voltage, the liquid crystals contained in the polymer are arbitrary oriented, and the incident light is scattered. The liquid crystals form a milky-opaque, opaque surface, which serves as an effective privacy screen or as protection against incident light. When an electric voltage is applied, the liquid crystals uniformly align and the layer becomes clear. However, very high transparency is only achieved with a view perpendicular to the layer. At oblique incidence of light or oblique viewing angle, a slight scattering of the light can be observed even with electrical voltage.

The condition described is a "Normally Black Mode". By appropriate arrangement of the film or several LC films but also a "Normally White Mode" can be set up. The light falls through when switched off. Only by applying a voltage, the PDLC element can be clouded or a light protection can be established. Alternatively, an element in "Normally Black Mode" can be converted into a mode that corresponds to a "Normally White Mode" by means of a suitable electrical connection.

According to the second variant of the electro-optically switchable system described above, the optically active element prevents the passage of light in the visible wavelength range at least partially when the voltage is not present and allows increased passage of light in the visible wavelength range by closing the electrical circuit.

In this embodiment, the optically active element is preferably a photoelectrochromic element which, when not switched on, darkens under illumination and becomes substantially transparent by closing the electrical circuit independently of the external illumination state of the system. A photoelectromotive element combines the mechanisms of action of an electrochromic layer and an electrochemical solar cell. The charge transfer takes place via transparent, electrically conductive layers on glass substrates. The layer is switched via an external circuit: If the external circuit is open under irradiation, the layer becomes colored. If the circuit is closed, the layer decolorizes, even under irradiation. The coloring is retained as long as the switch remains open. In a preferred embodiment of the second variant, the probe comprises a photodiode or consists of a photodiode. It is also possible in this embodiment that the probe comprises a solar cell or consists of a solar cell. However, the use of a solar cell is not as advantageous in all respects as in the first variant, since when switching (switch on) of the electric circuit is closed so as to prevent the passage of light at least. If the solar cell is darkened for switching, it is not available as a power source, so that after the second variant also when sowing a solar cell as a probe usually a conventional power source is required.

Photodiodes are semiconductor diodes that convert visible light into an electrical current. They are used in light barriers, remote controls with infrared radiation (remote controls) and in light measurement. They are used in optical transmission systems and in solar cells. In the present invention, a photodiode is used to convert light into a voltage signal.

The switching states according to the second variant using a photodiode can be summarized as follows:

That means:

- When light or bright environment, the optically active element turns dark.

- In a dark environment, the optically active element decolorizes and becomes transparent.

- With complete darkening of the photodiode (or alternatively a solar cell) (button function, switch on), the optically active element is transparent, regardless of the external illumination state.

The subject matter of the present invention is likewise a packaging which comprises an electro-optically switchable system according to the invention.

A packaging is understood to mean the targeted, detachable coating of a product. Certain products such as bulk materials, liquids or gases are packed in containers. Suitable packages are, for example, pouches, bottles, tubes, buckets, crates, cartons, cardboard boxes or cans. Suitable materials for packaging are, for example, paper, plastic, wood, metal, tinplate, glass, cardboard, etc.

In a suitable embodiment, a light source for the button is additionally provided. In the context of the present invention, a light source is understood to mean a place of origin of light and in particular of light in the visible wavelength range. This is in particular an artificial light source. The light source can be both first order and second order. First-order light sources are self-illuminating light sources. These include, for example, lamps. Second-order light sources are bodies that only reflect light and do not shine themselves. These include z. Reflectors on vehicles and clothing and all other bodies that reflect light. The light source may be a point light source, a diffused light source, or a combination thereof.

The provision of a light source for the button should ensure that the external lighting status of the button is always the same. Thus, the electrical circuit can be switched completely independent of the lighting condition of the environment. In a preferred embodiment, the packaging according to the invention is used for merchandise to be protected from the influence of light.

Sales goods are consumer goods that are manufactured and traded for private consumption or consumption. It can be durable durable goods that are not consumed in the strict sense, but by the repeated use of wear (wear) subject, and in particular to consumer goods, such. As foods, medicines, personal care products, etc. act. Goods for sale can be "convenience goods", ie normally goods with a comparatively low price, or goods of search and comparison shopping ("shopping goods"), ie goods with a higher price than goods of everyday use , or special products and specialties ("specialty goods"), ie luxury goods with a comparatively very high price. When purchasing these goods or merchandise, comparisons are made during the purchase decision to select the best possible alternative. Such merchandise is often to be kept protected from exposure to light to maintain quality over the longest possible period. The packaging can not only take over a protection, storage, loading and transport, dosing and removal function in the sale. It can also serve as sales packaging as an aid to streamline the sales process or, if appropriate, as sales packaging with additional benefits. Furthermore, it can make a sales and / or advertising function by their geometric or color design and / or as a carrier informing inscriptions and images. The sales packaging allows the buyer to recognize the product, whether by name, logo, color or shape of the packaging. It also has an information function. The packaging The product identifies the type, quantity, weight and price, informs about dangerous goods information, expiry dates and intended use, and it also carries encrypted data (barcodes). For example, the printed EAN code enables fast reading at scanner cash registers.

Appealing sales packaging promotes sales, thereby increasing sales and winning new customers. The sales packaging often gives the first and purchase crucial impression. Another object of the present invention is the use of the electro-optically switchable system according to the invention in a container for substances that are to be kept protected from the influence of light.

In particular, the electro-optically switchable system according to the invention is used in a packaging for merchandise which is to be kept protected from the influence of light.

In the context of the use according to the invention of the electro-optically switchable system, the sale goods are in particular light-susceptible foods, pharmaceuticals, cosmetic products or tobacco or tobacco products.

Foods are understood here as substances or products that are absorbed by humans for the purpose of nutrition and / or enjoyment through the mouth. They may be prepared in advance. Foods include, in particular, food supplements, dietary supplements and food additives. The foods may be of vegetable origin, such as vegetables, fruits, legumes, nuts, mushrooms, cereals (dry) products, vegetable edible oils and fats, confectionery, coffee, tea, cocoa, herbs and spices, or Products of animal origin, such as dairy products, but also to water, salt, beverages or processed products, such as convenience products act.

A variety of products in the sale is susceptible to light, d. H. There is a high photochemical hazard for these products or their ingredients. Important possible influencing factors for a light damage of a product, in particular a food are:

^■ the intensity (total energy) of the light striking the food,

^■ the color of the incident light (spectral energy distribution),

■ the residence time of the food in the light,

^■ the simultaneous presence of light and oxygen,

^■ the temperature, ^■ the composition of the product:

Light absorption behavior of the product,

endangered ingredients,

- possible reaction types of the constituents,

Presence of sensitizers and inhibitors.

A light-induced reaction does not primarily depend on the light that is offered to the food, but on the absorbed light component, ie. H. on the absorbed energy. The following processes of damage to food by light can occur individually, in parallel, mutually reinforcing, in competition or as a follow-up reaction:

^■ light-induced autooxidation of unsaturated fats,

■ photosensitized oxidation (photo-oxidation) of fats and protein,

^■ photosensitized oxidation of dyes,

^{■ Deterioration} of dyes by the influence of light.

For example, the sensitivity of edible oils to light-induced reactions with oxygen (photooxidation) is known. Photolytic processes in milk and milk products can lead to light-induced flavor defects, such. B. the formation of a tallow-rancid taste, a so-called "light taste", and a light-induced vitamin degradation (loss of ascorbic acid) lead. Cocoa butter is susceptible to oxidation under the influence of light. In particular, white chocolates, milk chocolates and chocolates with deposits such as nuts are therefore particularly susceptible to light. In the case of chlorophyll-containing plant constituents, fat oxidation can be triggered under the action of light. In the case of meat or fish, the presence of hematin compounds may favor auto-oxidation. In muscle meat, metmyoglobin formation (the color change from red to gray) may be promoted by light. Ground paprika decolorizes, for example, under the influence of light. Paprika spice is perceived by the consumer but only with an intense coloration as a high quality product. Even frozen goods are susceptible to light: the red coloration of frozen beef remains only about three days when exposed to light, but three months in the dark.

Usually, such light-sensitive products are therefore in light-tight packaging, eg. As bags, boxes, etc. offered. However, light-tight packaging does not allow a view of the interior of the packaging and thus of the product. This is particularly disadvantageous if the prospective buyer wants to assess the quality of a product on the basis of its appearance. As a quality criterion in particular high-priced food is often the outer nature of the product such as granularity or fineness, z. For example, in ground products, the color, z. For example, in spices, etc. So that the potential buyer can judge the appearance of the product, packaging must therefore allow a visual inspection of the product. Purchase decisions are predominantly made unconsciously emotionally. Unconscious stimuli usually lead quickly and immediately to a purchase decision. The special character of a product (new, improved, fresh, exclusive, etc.) plays a decisive role, as it awakens curiosity and interest in the product. Playing with expectations, the longing for the imaginative, including packaging that appeals to the play instinct, are in vogue. Design has become a key element in all areas of the consumer world and is seen as an additional product benefit. Last but not least, design serves as the key to product differentiation. After all, it is no longer enough to simply pack a product. The packaging must reflect the benefits and values of a product.

The novel packaging thus not only allows the prospective buyer to subjectively evaluate the quality of the goods and still protect the goods from the damaging effects of light. A corresponding design of the novel packaging can also trigger a targeted sales incentive for the customer.

The electro-optically switchable system according to the invention and especially a packaging according to the invention consists essentially of two components: an optically active element and a sensor based on a photovoltaic effect, the probe preferably comprising a solar cell or consisting of a solar cell. The power is preferably generated by light on the solar cell, which z. B. flexible or rigid, (poly) crystalline or dye-based. For the technical realization of a device according to the invention commercially available components can be used. Polycrystalline solar cells are standard articles and can for example be obtained from Conrad Electronics. These include solar cells labeled "SOLAR CELL 5 V / 81 MA" (http://www.conrad.de/ce/de/product/191321/SOLARZELLE-5- V81 MA, April 2010). These have a nominal voltage of 5V. Dye solar cells can be obtained, for example, from G21 i, Cardiff, Wales

(www.g24i.com, April 2010). In a particular embodiment, these are flexible and thus suitable for use on curved surfaces.

An LCD unit suitable for self-darkening can be used, for example, by Nemoptic (1, rue Guynemer, 781 14 Magny les Hameaux, France, www.nemoptic.com, April 2010) or by Densitron (www.densitron.com, April 2010; Article LMR37338)). It is a flexible, transmissive, LCD unit, which can be switched between transparent and black depending on the voltage state. The applicable switching voltage is between 3 and 5V depending on the LCD type. A grid of so-called dots is sufficient in this case, so that no further control electronics must be used. Exceptions to this are, of course, applications where imaging is desired (for example, for promotional purposes).

FIGS. 1 a and 1 b as well as 2 a and 2 b each represent a possible embodiment of an electro-optically switchable system according to the invention. FIGS. 3 to 6 show possible uses of the electro-optically switchable system according to the invention in containers, more particularly in packaging. These figures are intended to illustrate the present invention without limiting it to the figures.

The following reference symbols are used in FIGS. 1a to 2b and 3 to 6:

1 = transparent foil or wall,

2 = optically active element,

3 = opaque film or wall,

4 = solar cell.

FIGS. 1a and 1b show a simple embodiment of the electro-optically switchable system according to the invention. The optically active element 2 and the solar cell 4 are located on a transparent film or wall 1, which serves as a carrier. They are embedded in this carrier in an opaque film or wall 3. Thus, visible light can only penetrate through the system in the area of the optically active element.

1a, the solar cell 4 is covered from above (darkened), so not exposed to the light (incident from above, not shown). In this case, the optically active element 2 is transparent. Light can thus pass through the optically active element 2 in the direction of incidence (from top to bottom, not shown).

If the solar cell is not covered from above, ie is exposed to the light (incident from above, not shown), as shown in FIG. 1 b, then the optically active element becomes essentially opaque to light.

FIGS. 2a and 2b show a second embodiment of the electro-optically switchable system according to the invention. The optically active element 2 is located on a transparent film or wall 1, which serves as a carrier. It is embedded on this support in an opaque film or wall 3. The solar cell 4 is embedded in a further transparent film or wall 1. This second transparent film or wall 1 covers the opaque film or Wall 3 and the optically active element 2 completely. Also in this arrangement visible light can only penetrate through the system in the region of the optically active element. In Figure 2a, the solar cell 4 is covered from the left, so not the light (incident from the left, not shown) exposed. In this case, the optically active element 2 is permeable to light in the visible wavelength range. Thus, light can pass through the optically active element 2 in the direction of incidence (from left to right, not shown). If the solar cell is not covered from the left, ie is exposed to the light (incident from the left, not shown), as shown in FIG. 2b, then the optically active element becomes substantially opaque.

The embodiments illustrated in FIGS. 1 a to 2 b are suitable for rigid or flexible optically active elements. The construction can be done on rigid or flexible and flat or curved surfaces. Such a window formed can be designed in different sizes up to a band or even a complete coat. Behind or within the container located substances are effectively protected from exposure to light.

The embodiment shown in FIGS. 2a and 2b is particularly suitable for use in a "TetraPak®" multilayer packaging. Again, the window can be designed in different sizes up to a band or even a complete coat.

FIGS. 3 to 6 each show a possible design of a package with a novel electro-optically switchable system integrated therein.

FIG. 3 shows a cuboid container with a switchable viewing window. The viewing window consists essentially of an optically active element 2 and is switchable by means of a solar cell 4 between transparent and opaque. The container itself consists of opaque walls 3. The optically active element and the solar cell are arranged on one side of the cuboid at a small spatial distance.

The arrangement in Figure 3 allows a view of the product located in the container.

FIG. 4 also shows a cuboid container, but with two switchable viewing windows facing each other. The viewing windows essentially consist in each case of an optically active element 2 and are simultaneously switchable between transparent and opaque by means of a solar cell 4. The container itself exists made of opaque walls 3. The solar cell and an optically active element are arranged on one side of the cuboid at a small spatial distance.

The arrangement in Figure 4 allows a review by the container and thus a more comprehensive assessment of the product contained therein.

The design shown in Figures 3 and 4 is particularly suitable for rigid or low deformable packaging, such as tablet boxes. Also, a use for a refrigerator door is possible.

Figure 5 shows a cylindrical container with a switchable window. The viewing window consists essentially of an optically active element 2 and is switchable by means of a solar cell 4 between transparent and opaque. The container itself consists of opaque walls 3. The viewing window or the optically active element extends in the form of a banderole completely around the cylinder jacket.

The arrangement in Figure 5 allows a review by the container and thus an all-around assessment of the product contained therein.

FIG. 6 likewise shows a cylindrical container with a switchable viewing window, comparable to FIG. 5. The viewing window or the optically active element, however, occupies only a section of the cylinder jacket. The arrangement in Figure 6 allows a view of the product located in the container.

The design shown in Figures 5 and 6 is particularly suitable for cans or bottles.

In addition, a fully flexible film solution is still possible. Similar to Figures 3 and 4, but with a very small in a spatial orientation expansion, one can get a bag or bag when using a flexible film. The optically active element can then be designed as a slip-in light cover.

Claims

claims

1. Electro-optically switchable system, comprising - an optically active element which prevents the passage of light in the visible wavelength range at least partially in the illuminated state and by switching an electrical circuit allows increased passage of light in the visible wavelength range, and - one on a photovoltaic Effect based push button for the

Duration of actuation of the probe increases the passage of the light, wherein the passage of the light by pressing the button can be increased substantially independently of the external illumination state of the system.

2. Electro-optically switchable system according to claim 1, wherein the probe comprises a solar cell or consists of a solar cell.

3. Electro-optically switchable system according to one of claims 1 or 2, wherein the optically active element at least partially prevents the passage of light in the visible wavelength range and allows the interruption of the electric circuit, an increased passage of light in the visible wavelength range at least partially.

The electro-optically switchable system of claim 3, wherein the optically active element comprises liquid crystals.

5. Electro-optically switchable system according to claim 4, wherein the optically active element comprises at least two liquid-crystalline layers which have the same chirality and which absorb in a similar wavelength range.

6. The electro-optically switchable system according to claim 5, wherein the optically active element comprises at least two chiral nematic layers having the same chirality and absorbing in a similar wavelength range.

7. Electro-optically switchable system according to claim 4, wherein the optically active element comprises polymer-dispersed liquid crystals.

8. Electro-optically switchable system according to one of claims 1 or 2, wherein the optically active element at least partially prevents the passage of light in the visible wavelength range at undamped voltage and closing the electrical circuit allows increased passage of light in the visible wavelength range.

9. Electro-optically switchable system according to claim 8, wherein it is the optically active element is a photoelectrochromic element that darkens under illumination and dark by closing the electrical circuit, regardless of the external illumination state of the system is substantially transparent.

10. An electro-optically switchable system according to claim 9, wherein the probe comprises a photodiode or consists of a photodiode.

1 1. container comprising an electro-optically switchable system according to one of claims 1 to 10.

12. A container according to claim 1 1, wherein in addition a light source for the button is provided.

13. A container according to any one of claims 1 1 or 12 for merchandise to be protected from light.

14. Use of an electro-optically switchable system, as defined in any one of claims 1 to 10, as a component of a container which allows for the duration of actuation of the probe increased light transmission into its interior.

15. Use of the electro-optically switchable system, as defined in any one of claims 1 to 10, as a component of a container for substances that are to be stored protected from light.

16. Use according to claim 15 in a packaging for merchandise that should be kept protected from the influence of light.

17. Use according to claim 15, wherein the sales goods are food, food supplements, pharmaceuticals and / or cosmetics.

18. Use of a container comprising an electro-optically switchable system as defined in any one of claims 1 to 10, as a package for protecting products packaged therein from the damaging action of light.

19. Use of a container, comprising an electro-optically switchable system as defined in any one of claims 1 to 9, as a package for increasing the consumer appeal in a consumer.