WO2000052521A2

WO2000052521A2 - Decorative element

Info

Publication number: WO2000052521A2
Application number: PCT/EP2000/001880
Authority: WO
Inventors: Gerhard Schmidmayer; Siegfried Müller; Klaus Vornhof; Grégoire WITZ; Markus Kerkhoff
Original assignee: Bayerische Motoren Werke Aktiengesellschaft; Delphi Technologies, Inc.
Priority date: 1999-03-04
Filing date: 2000-03-03
Publication date: 2000-09-08
Also published as: EP1230580A2; DE19909471A1; WO2000052521A3

Abstract

A decorative element (1) for the interior fittings of a motor vehicle has a coloured carrier layer (2) with a liquid crystal cell (4) whose liquid crystal polymer layer (7) consists of side-chain polymers loaded with dye (8). The mixed colour from the pigment in the carrier layer (2) and the dye (8) can be changed by altering the orientation of the carrier chains of the side-chain polymers. The invention hereby provides a simply constructed, low-cost decorative element (1) which allows the motor vehicle user to individually change the colour of the interior of his or her motor vehicle.

Description

Decorative element

The invention relates to a decorative element that can be used, for example, on visible surfaces of everyday objects or furnishings (for example on furniture, electrical appliances, in the interior of motor vehicles, etc.).

Known decorative elements are strip-shaped or flat as decorative strips or decorative surfaces. The known decorative elements have, for. B. the appearance of a certain material (metal, wood, etc.) or have a certain color or a certain pattern in order to stand out clearly from the surface of the utensil or furnishings.

The object of the invention is to further develop the known decorative elements.

This object is solved by the features of claims 1 or 2. Claims 9 and 10 describe liquid crystal cells which are suitable, for example, for forming decorative elements according to the invention. Claims 1 1 and 12 relate to methods for controlling decorative elements according to the invention.

The main idea here is to design the decorative element in such a way that it changes color with appropriate control. In this way, the appearance of the utility and furnishing item can be changed in color, for example from solid to cheerful, from calming to stimulating, depending on the respective basic attitude of different people or also “depending on the forehead. mungsiage 'by one and the same person The color changes - without changing the decorative elements - by appropriate control

For this purpose, the decorative element according to claims 1 and 2 has at least one liquid crystal cell, which represents a further development compared to known liquid crystal cells, as described, for example, in JP 54-60894 A1. The matrix of the known liquid crystal cells contains molecules to which dyes are attached Which, depending on the control of the liquid crystal cell, are aligned uniformly perpendicular to the surface of the liquid crystal cell or are distributed in the matrix without being aligned. Such liquid crystal cells are generally known under the name LCD (liquid crystal display)

In liquid crystal cells according to claims 1 and 2, in contrast to known cells which contain chiral molecules in a low-viscosity material, the matrix consists of a highly viscous liquid polymer polymer layer. This liquid polymer layer essentially consists of a side chain polymer, on the carrier chains of which dyes (for example antraquinones) are copolymerized The liquid crystal cells according to the invention are accordingly referred to as LCP (liquid crystal polymers) .The solid-body properties of the liquid crystal polymer layer result in the advantage of a simplified structure of the liquid crystal cells according to the invention, which, in contrast to known cells, no longer require a solid support substrate (e.g. glass or plastic plates), but instead can be applied to a film-like substrate

With an LCP according to claim 1, by applying an AC voltage of a first frequency, a tilting of the carrier chains is achieved with a first tilting direction. With the tilting of the carrier chains, the dyes attached to the carrier chain also change their orientation accordingly. By applying an AC voltage with a second frequency, the carrier chains become Tipped back in the direction of its starting position with the opposite sense of tipping. The possibility created according to the invention to produce opposite tipping movements of the carrier chains means that a certain amount is taken up Tilting angle of the carrier chains and moving back into the starting position are possible in a simple manner without having to carry out a rotation of the carrier chains by 180 °. Depending on the liquid polymer polymer layer used, “further rotation” is also not possible without destroying the screw-like structure of the carrier chains

Liquid crystal cells according to claim 2 differ from known liquid crystal cells in that the carrier chains assume a different tilt angle depending on the intensity of the electric field. Depending on the orientation of the carrier chains, the attached dyes are oriented more or less perpendicularly to the surface of the decorative element and thus more or less strongly Visible While in known liquid crystal displays the change between two defined states takes place as quickly as possible due to the low viscosity of the matrix without any noticeable intermediate stages, the high viscosity according to the invention of the liquid crystal polymer layer results in a comparatively slow ingestion and subsequent holding of any intermediate stages

Various influencing factors are important for the electro-optical stability of the system, in particular the viscosity of the liquid knstall polymer layer and the temperature. Adherence to a defined tilt angle can be controlled via the "elastic constants" of the LCP, including the bending, torsion and cantilever constant ("Splay" constant) of the liquid stall polymer layer is to be understood. The liquid stall polymer layer can consist of different groups of polymers with different structures

By arranging at least two liquid crystal cells with dyes of different colors one above the other (claim 3), a decorative element is created in which mixed colors can be produced, depending on the orientation of the carrier chain in the individual liquid crystal cells In a decorative element according to claim 4, alternating mixed colors can be produced in a single liquid crystal cell depending on the control. This is achieved in that the liquid crystal cell contains different types of carrier chains, the tilting movement of which can be initiated with alternating voltages of different frequencies Dyes of different colors are deposited, different mixed colors can be generated in a single element via the level of the alternating voltages applied

By means of a carrier layer with a specific color (claim 5), as known per se from JP 54-60894 A1, the carrier chains with the attached dyes can, depending on the control of the liquid crystal cell, be aligned uniformly perpendicular to the surface of the liquid crystal cell or under one that deviates from the perpendicular Angles are set so that different mixed colors are produced as the visible color of the decorative element, which are determined more or less by the color of the support layer or the color of the dyes

According to claim 6, it is proposed to design the decorative element in a film-like manner, as already known per se from WO 98/13722 A1. The flexibility of the support layer means that the decorative element also adapts to curved surfaces. To avoid color deviations in the curved areas, the decorative element must be designed in this way that the thickness of the liquid crystal cell, and thus its color, does not change even in the curved areas. The film-like structure with a small thickness of the decorative element enables a wide range of uses, even in areas with little free space Decorative element can also be produced and arranged in different geometric shapes

The liquid crystal cells of the decorative elements are preferably designed in such a way that the color set by an alternating voltage with a specific frequency and voltage level is retained even after the voltage has been removed in order to to keep the decorative elements low. Furthermore, the stress-free state slows down the decomposition and the aging process in the liquid knstall polymer layer

The invention is shown in the drawing using possible exemplary embodiments and is explained in more detail below. It shows

FIGS. 1 to 3 a decorative element according to the invention in section, in different operating states,

FIG. 4 shows a decorative element composed of two liquid crystal cells,

FIG. 5 shows a decorative element with a liquid crystal cell with different active carrier chains,

Figure 6 is a diagram showing the dependence of the tilt angle of the support chains on the level of the applied voltage and

7 shows a perspective view of the interior of a motor vehicle, with decorative elements inserted into the interior of the motor vehicle

1 to 3 has an underside support layer 2 and an upper-side cover layer 3, between which a liquid crystal cell 4 is arranged. The liquid crystal cell 4 consists of a first and a second electrode 5 or 6 with an intermediate one Fluffy Knstall polymer layer 7 made of side chain polymers The side chain polymers are formed by carrier chains in the form of helical macromolecules, which serve as a supporting structure for the actual functional building blocks, the side chains. copoly- measured by the mesogens, the spatial alignment of the carrier chains takes place in the liquid knstall polymer layer 7

An AC voltage source 10 is connected to the two electrodes 5 and 6 via a button 9. The frequency of the AC voltage can be changed via a step switch or a potentiometer 11. The top side of the carrier layer 2 facing the electrode 5 is colored with a first color shade A. , while the dyes 8 have a second color shade B. The electrodes 5 and 6 and the cover layer 3 are transparent

The carrier and cover layers 2 and 3 consist, for example, of PI, PET, PPP, PEN, PENBB, PC, COC, PPS, PES, PEEK, PMMA or LCPs in the form of high-strength main chain polymers, as detailed in WO 98/13722 A1

In a first state (FIG. 1), the carrier chains in the liquid knstall polymer layer 7 are aligned parallel to the cover layer 3 in the homootropic state or approximately parallel in the “focal conic state”. In other words, the main axis of the carrier chains closes with the plumb line (line of sight) Liquid crystal cell 4 at an angle of 90 ° (homootropic state) or approximately 90 ° (focal-conic state). The dyes 8 attached to the screw structure of the carrier chains are oriented approximately in the direction of the solder and thus do not appear significantly, so that the color of the decorative element 1 is largely determined by the color shade A of the support layer 2 (FIG. 1)

If an alternating voltage with a certain first frequency, which is matched to the spin of the carrier chains, is applied to the electrodes 5 and 6, the carrier chains are tilted as a function of the level of the alternating voltage with respect to the homootropic or the focal conic state that, depending on the size of the tilt angle of the carrier chains, the dyes 8 with their hue B become more or less visible. A mixed color between the two hues A and B arises which, depending on the "inclination" of the carrier chains, is more or less strongly affected by the dyes 8 is determined when the The main axes of the carrier chains in the direction of the solder onto the liquid crystal cell 4 (angle between the solder and the main axis of the carrier chains is approximately 0 °, "planar state"), the visible color tone is determined exclusively by the dyes 8, a corresponding density of dyes 8 in the liquid crystal polymer layer 7 provided (Figure 2) Figure 3 shows an intermediate position of the carrier chains at a certain tilt angle < ^χ °, in which a mixed color of A and B is established

The initiation of the tilting movement of the carrier chains takes place by applying an alternating voltage with a certain frequency, while the magnitude of this alternating voltage determines the magnitude of the tilt angle <χ. A liquid polymer polymer layer 7 with carrier chains is preferably used, in which the carrier chains are tilted by an alternating voltage of a first frequency and the (back) tipping of the carrier chains with the opposite direction of rotation is triggered by an alternating voltage of a second frequency

If the color shade A of the support layer 2 is not "colored", but black, white or (colorless) reflective, then in the narrower sense, with different inclined positions of the support chains, no mixed colors from A and B arise, but only different color intensities of the color shade B

In addition, the Flussigknstall polymer layer 7 itself has an inherent color due to the "selective reflection" given by the screw structure of the carrier chains, provided that the pitch of the screw structure is in the range of the wavelength of visible light. If the pitch of the screw structure is in the range of the wavelength of infrared or ultraviolet light, so the liquid knstall polymer layer 7 appears "colorless"

By arranging two liquid crystal cells 4 with dyes 8 of different hues C and D one above the other, the spectrum of possible mixed colors can be expended (FIG. 4). Deviating from the illustration according to FIG. 4, a carrier layer 2 with a specific hue A can of course be dispensed with FIG. 5 shows a decorative element 1 with a single liquid crystal cell 4, which contains two different groups of carrier chains, to which dyes 8 of different hues C and D are attached. The tilting movement of the individual groups of carrier chains is initiated in a differentiated manner via alternating voltages with different frequencies Mixed colors of a wide spectrum can also be generated, with or without the use of a carrier layer 2 with a color shade A.

Of course, the decorative elements 1 can also be composed of more than two liquid crystal cells 4. Likewise, the liquid crystal cell 4 can also contain more than two groups of side chain polymers

The decorative elements 1 work in the reflective mode in that incident light is finally reflected with a mixed color depending on the color A or the reflective properties of the support layer 2 and depending on the orientation of the dyes 8 with the color B or the colors C, D etc.

The diagram according to FIG. 6 explains the relationship between the magnitude of the applied AC voltage U (abscissa) and the tilt angle oc (ordinate) of the carrier chains.The dashed line shows the characteristics of known liquid crystal displays in which, in the interest of a quick color change, the tilting of the molecules in a Defined voltage U _kιpp takes place suddenly. The tilting of the support chains of the liquid crystal cell 7 of the decorative element 1 according to the invention, however, takes place according to an approximately linear relationship (solid line), so that any number of stable intermediate layers with an individual tilt angle <χ can be set

Decorative elements 1 according to the invention can be used, for example, to design the interior of a motor vehicle. FIG. 7 shows possible arrangements of decorative elements 1 at different locations on the vehicle interior, which include an instrument panel 20, a center console 21 and Door panels 22 have a decorative element 1 according to the invention in the form of a trim strip both in the area below an instrument cluster 23 and below a passenger-side storage surface 24. The decorative elements 1 each extend from the end section of the instrument panel 20 on the outside of the vehicle to a section 25 drawn into the instrument panel 20 Center console 21 The line formed by the decorative elements 1 in the instrument panel 20 is never continued by further decorative elements 1 in the door panels 22 (shown here only on the passenger side) at the level of the breast

In addition, further decorative elements 1 are inserted into the center console 21 between control panels 26, storage compartments 27 and an operating element 28. In addition to the illustrated decorative elements 1, purely strip-shaped decorative elements 1 are also possible to form colored decorative lines. On the other hand, the decorative elements 1 according to the invention can also be used over a large area, for example in a door nencover 22, are used

The color of the decorative elements 1 can be changed by appropriate control in order to influence the appearance of the vehicle interior. Both a uniform color of all decorative elements 1 and a different coloring of the individual decorative elements 1 is possible

Claims

claims

1. Decorative element (1) with at least one liquid crystal cell (4), which has two electrodes (5, 6) and an intermediate liquid crystal polymer layer (7), which contains side chain polymers with carrier chains, to which dyes (8) are attached, the liquid crystal polymer layer (7) is such that under the action of an alternating voltage (U) applied to the electrodes (5, 6) at a first frequency the carrier chains in a first direction and under the action of an alternating voltage (U) with a second frequency the carrier chains in one Direction opposite to the first direction.

2. Decorative element (1) with at least one liquid crystal cell (4), which has two electrodes (5, 6) and a liquid crystal polymer layer (7) arranged between them, which contains side chain polymers with carrier chains, to which dyes (8) are attached, the liquid crystal polymer layer (7) is such that under the action of an AC voltage (U) applied to the electrodes (5, 6) with a certain frequency, the carrier chains in

Depending on the level of the applied AC voltage (U) can be tilted more or less. Decorative element according to claim 1 and / or 2, characterized in that at least two liquid crystal cells (4) are arranged one above the other

Decorative element according to claim 1 and / or 2, characterized in that the liquid crystal cell (4) contains a liquid knstall polymer layer (7) with at least two types of different side chain polymers which is influenced by an alternating voltage (U) applied to the electrodes (5, 6). behave differently

Decorative element according to one of the preceding claims, characterized in that the liquid crystal cell (4) on a colored

Carrier layer (2) is arranged

Decorative element according to one of the preceding claims, characterized in that the decorative element (1) is film-like, with a support layer (2) on the underside, two electrodes (5, 6) with a liquid polymer polymer layer (7) arranged between them and an upper cover layer (3)

Decorative element according to claim 6, characterized in that the electrodes (5, 6) are formed by thin layers of indium tin oxide (ITO)

Decorative element according to one of the preceding claims, characterized in that the decorative element (1) can be used in the interior of a vehicle

Liquid crystal cell (4) with two electrodes (5, 6) and an intermediate liquid crystal polymer layer (7), which contains side chain polymers with carrier chains, to which dyes (8) are attached, the liquid crystal polymer layer (7) being such that under Effect of one on the Electrodes (5, 6) applied AC voltage (U) at a first frequency, the carrier chains are tilted in a first direction and under the action of an AC voltage (U) with a second frequency the carrier chains are tilted in a direction opposite to the first direction.

10. liquid crystal cell (4) with two electrodes (5, 6) and an intermediate liquid crystal polymer layer (7), which contains side chain polymers with carrier chains, to which dyes (8) are attached, the liquid crystal polymer layer (7) being such that under Effect of an alternating voltage (U) applied to the electrodes (5, 6) with a specific one

Frequency the carrier chains are tilted more or less depending on the level of the applied AC voltage (U).

1 1. Method for controlling a decorative element according to one of claims 1 to 8, characterized in that the decorative element (1) is controlled individually by an operator.

12. A method for controlling a decorative element according to one of claims 1 to 8, characterized in that the decorative element (1) is controlled depending on environmental conditions and / or the state of the object on which the decorative element (1) is arranged.