Skin for vehicle interior trim parts including light sources

Abstract

The skin (1) includes at least a translucent elastic layer (5) made of colored plastic material, and the translucent elastic layer includes at least one first portion (8) configured to be located in front of a light source (9). Due to the presence of surface irregularities (17, 18) on the surface of the translucent elastic layer, the light from the light source produces an image on the first portion of the translucent elastic layer. When its colored plastic material has a thickness of 1.0 mm... ‑1 Up to 25mm ‑1 The average spectral attenuation coefficient (α) between av When providing even a small difference in the thickness of the semi-transparent elastic layer, a clearly visible image can be obtained. The layer thickness difference (d2-d1) and the average spectral attenuation coefficient (α) are... av It should also be large enough to satisfy the formula: α av (d2-d1)>-lna, where a equals 0.50. Because surface irregularities can be automatically generated when the translucent elastic layer is formed against the mold surface, images can be easily obtained at the correct position on the skin.

Description

Technical Field

[0001] The invention relates to a skin for a vehicle interior trim component. The skin comprises at least a translucent elastic layer of a plastic material, usually substantially uniformly colored, having an outer surface and an inner surface opposite thereto. The outer surface forms the visible surface of the skin, the so-called A-surface. The translucent layer comprises at least one first portion configured to be placed in front of a light source and to transmit visible light generated by the light source from the inner surface to the outer surface. The light source is preferably adhered to the inner surface of the translucent layer. Background Art

[0002] Motor vehicles such as cars or trucks contain many electrical or electronic components that can be controlled by the driver or passengers. Operating elements for controlling the operation of these components, such as buttons, switches and sliders, are usually mounted mechanically individually or as a component in an opening in the decorative part itself. Between the areas with the operating elements, the decorative part usually includes areas formed by an elastic skin, which optionally has other functional or aesthetic components integrated in the skin. On its outer surface, the elastic skin has a surface texture. This texture can be used to imitate leather, but it can also be used to reduce the gloss of the skin material. This is important, for example, on the top of the dashboard to avoid too strong light reflections.

[0003] The operating elements can be adhered to the back side of the elastic skin. They can be provided with a light source so that they become visible through the skin. In the method disclosed in DE 10 2006 061 388, the skin is produced on the mold surface according to the powder melt process, and the operating elements are attached to the back side of the powder melt skin when the skin material has not yet been fully cured. In this way, the operating elements are adhered to the skin by the adhesion properties of the curing skin material. In a similar method disclosed in EP 2 275 307, the operating elements are attached to the back side of the first polyurethane skin layer before the reactive material for producing this skin layer is fully cured. Next, another polyurethane skin layer is sprayed on the back side of the first skin layer and the back side of the operating elements to embed the operating elements in the elastic polyurethane skin.

[0004] In recent years, there has been increasing interest in integrating operating elements in a nearly invisible manner in the skin. See, for example, US 7 638 719 and US 2019 / 0326908.

[0005] In US 7 638 719 the operating element is a pressure sensitive element covered by a flexible skin material, since in this way it is not visible to the user, an assignment field is provided on the outer surface of the skin to indicate the presence of the operating element.

[0006] In US 2019 / 0326908, a proximity sensor and a light source are arranged on the back of the skin. By means of an icon layer located between the light source and the skin, indicia can be projected onto the skin indicating the function of the electric or electronic component controlled by the switch assembly. The switch assembly is hidden unless activated by means of a light source to emit light. The disadvantage of the required icon layer is that it makes the operating components more complex and bulky.

[0007] A similar system is disclosed in US 2019 / 0161003. An automotive decorative component comprising an elastic skin, a light source, and an optical pattern layer located between the skin and the light source is disclosed. The optical pattern layer is capable of producing an image on the skin layer.

[0008] In the skin disclosed in KR 101680627, the letters or shapes are displayed on the outer surface of the skin not by means of an icon or optical pattern layer under the skin, but by means of some translucent skin color coatings and mask layers under these coatings. The letters and shapes are produced by cutting away a portion of the coating and mask layer by means of a laser so that at these locations the light from the light source can pass through the skin. The disadvantage of this system is that a post-processing laser process must be performed to accurately cut out the letters and shapes and to be located in the correct position in the skin. This post-processing is not only complicated, but also results in an additional amount of waste. Summary of the invention

[0009] The object of the present invention is to provide a new type of skin with a translucent elastic layer, through which an image can be generated by a light source attached behind the translucent layer, without the need for an icon or optical pattern layer located under the skin and without the need for additional post-processing processes, such as a laser cutting step.

[0010] The skin comprises at least a translucent elastic layer made of a colored plastic material, the translucent layer having an outer surface and an inner surface opposite to the outer surface, and the translucent layer comprises at least one first portion, the first portion being configured to be located in front of a light source and to transmit visible light generated by the light source from the inner surface to the outer surface.

[0011] In order to achieve the object of the present invention, the skin is characterized in that the first part of the semitransparent layer includes surface relief on its outer surface and / or inner surface to produce an image on the first part when the visible light is transmitted through the first part of the semitransparent layer, the surface relief forming at least one first area in which the thickness of the semitransparent layer is less than or equal to a first thickness (d1), and at least one second area in which the thickness of the semitransparent layer is greater than or equal to a second thickness (d2), the second thickness (d2) is greater than the first thickness (d1), and the difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is greater than 0.08 mm and less than 3.0 mm. The colored plastic material has an average spectral attenuation coefficient (α) in at least one visible light wavelength range. av ), the average spectral attenuation coefficient is the average value of the spectral attenuation coefficient (α(λ)) measured at fixed intervals, especially at different wavelengths (λ) at intervals of 5 nm, within the visible light wavelength range by the following formula (I):

[0012]

[0013] in:

[0014] d1 = said first thickness; and

[0015] T1(λ)=spectral transmittance at said wavelength (λ) of a film of said colored plastic material having a uniform thickness equal to said first thickness (d1 ) measured according to EN ISO 13468-2:2006, part 2.

[0016] According to the present invention, the average spectral attenuation coefficient (α av ) should further include 1.0mm -1 Up to 25mm -1 and should be related to the difference (d2-d1) between the first thickness (d1) and the second thickness (d2) according to the following formula (II):

[0017] α av (d2-d1)>-ln a (II)

[0018] in,

[0019] a=0.50.

[0020] The surface relief on the inner and / or outer surface of the translucent layer can be easily obtained by producing the translucent layer by a molding process. The surface relief can be produced against the surface of the mold or against an insert, in particular against the surface of a light source that can be placed in the mold beforehand. In this way, the image produced by the surface relief is always located at the correct position on the skin. In addition, the image is obtained automatically without the need for any icon or optical pattern layer below the translucent layer or any post-processing steps.

[0021] The surface concavity on the inner or outer surface of the translucent layer is preferably a molded surface concavity, i.e., a surface concavity obtained by molding a translucent elastic layer against a solid surface. In the case of an inner surface, the surface concavity can therefore be produced by molding a translucent layer against an inline layer already placed in a mold. Therefore, the translucent layer can be produced, for example, by a reaction overmoulding process (ROM), especially by a liquid polyurethane reaction mixture. However, the surface concavity is preferably arranged on the outer surface of the translucent layer. The surface concavity can be produced on the outer surface by molding a translucent layer against a textured mold surface, and the texture shows a negative mold of the surface concavity. The translucent elastic layer can be prepared by a thermoplastic material, which is molded against a mold surface in a molten state, such as a slush molding process. Alternatively, a layer (foil) of such a thermoplastic material can be molded against a mold surface in a solid state. The solid layer of the thermoplastic material is molded by applying enough pressure to force it or to make it be strongly adsorbed against a textured mold surface so that the negative surface concavity on the mold surface is transferred to the skin layer. The skin layer and / or the mold surface are preferably heated to assist the molding process. The elastic layer can also be produced from a reactive mixture, such as a polyurethane reactive mixture, which is applied in liquid form on the textured mold surface, such as by a spraying process, and allowed to cure on the mold surface.

[0022] Despite the fact that the colored elastic layer is translucent, it has been found according to the invention that when the average spectral attenuation coefficient of the colored plastic material is within 1.0 mm -1 Up to 25mm -1 When selected between , a clear visible image can be obtained by providing a relatively small difference in thickness of the layers. The higher the average spectral attenuation coefficient and the greater the difference in thickness between the first and second regions of the semi-transparent layer, the greater the contrast between the portions of the image produced by light passing through the thinner first region and the thicker second region of the semi-transparent layer. The average spectral attenuation coefficient is greater than 1.0 mm -1Make the semi-transparent layer opaque enough to produce a texture on it as usual, which is visible without any lighting from the back side of the semi-transparent layer, especially in areas where no light source is provided on the back side of the skin. On the other hand, the average spectral attenuation coefficient is below 25mm -1 This is essential for being able to produce a semi-transparent layer that still has a sufficiently high light transmittance at a sufficiently large thickness. The transmittance (T) is actually determined by the following formula:

[0023] T=e -α.d ,

[0024] in:

[0025] T is the light transmittance through the semi-transparent layer;

[0026] α is the attenuation coefficient of the material of the semi-transparent layer; and

[0027] d is the thickness of the semi-transparent layer.

[0028] According to the present invention, it has been found that when a is equal to 0.50 in the equation of formula (II), the thinner first region and the thicker second region can be visually distinguished. In other words, the light transmittance through the second region should be less than about 50% of the light transmittance through the first region.

[0029] According to the invention, in order to achieve the required transmittance difference between the first area and the second area, the thickness difference between the first area and the second area should be greater than 0.08 mm, in order to avoid that small thickness variations that are automatically obtained by the production process and cannot (easily) be avoided become visible. In addition, in order to achieve the required transmittance difference between the first area and the second area, the thickness difference between the first area and the second area should be less than 3.0 mm. In this way, no excessively large thickness difference is required to achieve the predetermined difference in transmittance between the first skin area and the second skin area. In other words, the desired image can be obtained with a relatively low surface relief that has only a minimal effect on the appearance of the skin, especially when it is not illuminated by a light source on the back of the translucent layer.

[0030] In an embodiment of the skin according to the invention, the value of a in formula (II) is equal to 0.45, preferably equal to 0.40, more preferably equal to 0.35, most preferably equal to 0.30.

[0031] This means that the light transmittance through the thicker second region includes at most about 45% or less of the light transmittance through the thinner first region of the skin, resulting in a relatively large contrast between the portion of the image produced by light passing through the first region of the skin and the portion of the image produced by light passing through the second region of the skin.

[0032] In an embodiment of the skin according to the invention, the difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is greater than 0.10 mm.

[0033] In this embodiment, the tolerance of skin thickness can be greater without causing visible defects in the image produced by light transmitted through the skin because a greater minimum thickness difference is required to achieve a predetermined difference in transmittance between the first skin region and the second skin region.

[0034] In one embodiment of the skin according to the invention, the difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is less than 2.0 mm, preferably less than 1.5 mm, more preferably less than 1.0 mm.

[0035] In this embodiment, an even smaller thickness difference is required to achieve a predetermined difference in transmittance between the first skin area and the second skin area. In other words, the desired image can be obtained with an even lower surface relief which has only a minimal effect on the appearance of the skin, especially when not illuminated by a light source behind the translucent layer.

[0036] In an embodiment of the skin according to the invention, the average spectral attenuation coefficient (α av ) greater than 2.0 mm -1 , preferably greater than 3.0 mm -1 , more preferably greater than 4.0 mm -1 , most preferably greater than 5.0 mm -1 .

[0037] In this embodiment, a smaller thickness difference is required to achieve a predetermined difference in transmittance between the first skin area and the second skin area. In other words, a desired image can be obtained with a lower surface relief which has only a small effect on the appearance of the skin, especially when not illuminated by a light source behind the translucent layer.

[0038] In an embodiment of the skin according to the invention, the average spectral attenuation coefficient (α av ) less than 20.0mm -1 , preferably less than 15.0 mm -1 , more preferably less than 10.0 mm -1 .

[0039] For the same skin thickness, a smaller attenuation coefficient results in a skin with a greater light transmittance. At the same time, a larger skin thickness difference is required to achieve a predetermined light-dark contrast in the image produced by the light source. A specific choice of the attenuation coefficient enables a clear image to be achieved in a thicker semi-transparent layer while maintaining the desired thickness difference between the thinner skin area and the thicker skin area, thereby producing a sufficiently small image.

[0040] In an embodiment of the skin according to the invention, the first portion of the translucent layer has an average thickness of less than 2.0 mm, preferably less than 1.5 mm, more preferably less than 1.2 mm, most preferably less than 1.0 mm. In another embodiment of the skin according to the invention, the first portion of the translucent layer has an average thickness of more than 0.2 mm, preferably more than 0.3 mm, more preferably more than 0.4 mm, most preferably more than 0.5 mm.

[0041] The average thickness is a surface-weighted average. The average thickness of a portion of the translucent layer is determined by dividing its volume by the surface area of ​​its inner surface.

[0042] The thickness of the translucent layer required in these embodiments makes it particularly suitable for use as a structural layer of the elastic skin, ie as a layer that contributes to the required mechanical properties of the elastic skin.

[0043] In an embodiment of the skin according to the invention, said visible wavelength range has a width of at least 50 nm, preferably at least 75 nm, or preferably at least 150 nm, or preferably at least 300 nm.

[0044] The light source may be a light source that emits only light within a specific wavelength range, such as an LED. When the above conditions are met for the wavelength range emitted by the light source (for example, when the translucent layer includes a color pigment, in particular, having the same color as the light emitted by the light source), the desired image can be produced as described above. On the other hand, when the light source emits light within a wider range, such as within the entire visible light wavelength range, and when the translucent layer includes a color pigment so that light within a specific wavelength / color range is mainly transmitted through the translucent layer, while other light is mainly absorbed, the effect of the present invention can be achieved by determining the average spectral attenuation coefficient within the transmission wavelength range.

[0045] In an embodiment of the skin according to the present invention, the visible light wavelength ranges from 380 nm to 780 nm.

[0046] This range includes all visible light wavelengths. Thus, images can be produced not only by white light, but also by light of other colors. Thus, two or more light sources can be placed behind a translucent layer so as to produce images in different colors depending on which light source is activated. Different light sources can be used alternately, or can be used together to produce differently colored portions of an image. The colored light source can include an LED that emits light in a specific wavelength range, or can include a light source that emits, for example, white light, which is covered by a colored transparent mask so that the colored light is transmitted through the mask into the translucent skin layer.

[0047] In an embodiment of the skin according to the invention, the skin comprises at least one light source adhered to the inner surface of the first portion of the translucent layer and configured to emit visible light having a predetermined wavelength range corresponding to the predetermined wavelength range.

[0048] In this embodiment, the average spectral attenuation coefficient is therefore determined over the wavelength range emitted by the light source, so that the above-mentioned effect is achieved by using this light source.

[0049] Preferably, the cover comprises an inner elastic layer adhered to the inner surface of the translucent elastic layer, and the light source is embedded between the translucent elastic layer and the inner elastic layer.

[0050] The advantage of this embodiment is that the light source is completely protected from dust or humidity. Furthermore, when the two skin layers are molded against the mold surface, the light source can be easily fully integrated so that it can be placed exactly at the desired position on the back of the translucent layer. Thus, when the skin is transferred to the next mold, especially the back foam mold, the light source is protected from any damage, wherein the substrate is adhered to the back of the skin through the transition of the foam layer.

[0051] The light source may comprise at least one LED, in particular a bare LED, embedded between the translucent elastic layer and the internal elastic layer.

[0052] Such bare LEDs are cheaper and smaller than embedded LEDs, so they can be easily integrated between the two skin layers.

[0053] In an embodiment according to the invention, the skin comprises a flat screen display, in particular an LED screen, more in particular an OLED screen, adhered to the inner surface of a second portion of the translucent layer, the second portion being configured to transmit visible light generated by the flat screen display from the inner surface to the outer surface.

[0054] With the above attenuation coefficient, especially with the smaller attenuation coefficient defined in the above preferred embodiment, the image of the display can be seen on the outer surface of the second part of the semitransparent layer.

[0055] Preferably, the inner and outer surfaces of the second portion of the translucent layer have a completely smooth surface texture or have a Pt value measured according to DIN EN ISO 4287:1998, which satisfies the following formula (III) in mm:

[0056]

[0057] Wherein b is greater than 0.50, preferably greater than 0.60, more preferably greater than 0.70.

[0058] In this embodiment, the image of the display is not distorted or is only minimally distorted by the presence of any surface texture on the outer or inner surface of the translucent layer. As on the first part of the translucent layer, the second part of the translucent layer can also be provided with surface reliefs to produce an additional image on this second part when the surface reliefs are illuminated by the display. The position of this additional image can be arranged to have no or only minimal influence on the image produced by the flat screen display itself.

[0059] Also preferably, the skin comprises an inner elastic layer adhered to the inner surface of said translucent elastic layer, said flat screen display being embedded between said translucent elastic layer and said inner elastic layer.

[0060] The advantage of this embodiment is that the display is completely protected from dust or humidity. Furthermore, when the two skin layers are molded against the mold surface, the display can be easily fully integrated so that it can be placed exactly in the desired position on the back of the translucent layer. Therefore, when the skin is transferred to the next mold, especially the back foam mold, the display is protected from any damage, wherein the substrate is adhered to the back of the skin through the transition of the foam layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Other advantages and details of the invention will become apparent from the following description of some specific embodiments of the skin according to the invention. This description is given by way of example only and is not intended to limit the scope of the invention. The reference numerals used in the description relate to the accompanying drawings, in which:

[0062] Figure 1 is a schematic perspective view of a trim component, in particular an instrument panel, comprising an elastomeric skin according to one embodiment of the invention;

[0063] Figure 2 is a schematic enlarged front view of a portion of the skin at the location of a first operating element with a light source, namely at the location of a pressure-sensitive switch sensor;

[0064] Figure 3 is a schematic cross-sectional view of a decorative component at the location of a pressure-sensitive switch sensor having a light source;

[0065] Figure 4 is a schematic enlarged cross-sectional view of a translucent layer of the skin at the location of a pressure sensitive switch sensor;

[0066] Figure 5 is a schematic cross-sectional view of a trim component at the location of a flat screen display integrated in the skin of the trim component; and

[0067] Figure 6 is lit by a light source behind the translucent skin layer Figure 2 Image of the first part of the semi-transparent skin layer shown in . DETAILED DESCRIPTION

[0068] The present invention generally relates to a skin 1 for a vehicle interior trim component 2 such as an instrument panel, door panel, console, glove box cover, etc. Figure 3 and Figure 5 As shown, the trim component comprises a skin 1 adhered to a rigid substrate layer 3. The skin 1 can be adhered directly to the substrate layer 3 by means of an adhesive or by means of an overmolding process, wherein the skin 1 is formed on the substrate layer 3 in a mold. Preferably, the skin 1 is adhered to the substrate layer 3 by means of a transition of a foam layer 4. The foam layer 4 can be produced between the skin 1 and the substrate layer 3 by means of a molding process.

[0069] The skin 1 according to the invention comprises at least one translucent elastic layer 5, which is preferably flexible, has an inner surface 6 and an outer surface 7, which forms the visible surface of the skin 1, i.e. the A-side. The translucent layer 5 is made of a plastic material that is preferably substantially uniformly colored. The term "plastic" includes all synthetic materials, including thermosetting and thermoplastic materials. The translucent layer 5 can be a thermoplastic layer or foil, in particular a TPE (thermoplastic elastomer) layer, such as a TPO or PVC skin. Such a thermoplastic skin layer can be formed by a thermoforming process or, for example, by a slush molding process. The elastic translucent skin layer 5 can also be made of a curable composition, in particular a curable polyurethane composition. The curable composition is a flowable material, which is applied to a mold surface and cured on the mold surface to produce a translucent skin layer 5.

[0070] The curable composition can be applied on the surface of an open mold by a spraying process, or it can also be applied in a closed mold, more specifically poured but preferably injected according to a reaction injection molding (RIM) process. A light-stable colored PU reaction mixture can be used. Reference may be made to EP-B-0 303 305, EP-B-0 379246, WO 98 / 14492, EP-B-0 929 586 and WO 04 / 000905, which are included herein by reference.

[0071] The translucent skin layer 5 is elastic, which means that it generally has an elongation of at least 30%, preferably at least 50%, measured according to DIN / EN / ISO 527-3. Its flexural modulus, measured according to ASTM D790-03, is preferably less than 100 MPa, more preferably less than 75 MPa, most preferably less than 55 MPa, even less than 40 MPa. Typically, its overall density is greater than 300 kg / m 3 , preferably greater than 500kg / m 3 , more preferably greater than 600 kg / m 3 .

[0072] In contrast to the translucent skin layer 5, the substrate layer 3 is relatively rigid and has in particular a flexural modulus measured according to ASTM D790 of greater than 500 MPa, preferably greater than 700 MPa. Although the substrate layer may be made of a thermosetting material, the substrate is preferably made of a thermoplastic material. The thermoplastic material is preferably selected from the group consisting of PC (polycarbonate), ABS (acrylonitrile butadiene styrene) and ABS blends, in particular PC / ABS, SMA (styrene maleic anhydride), PPO (polyphenylene oxide), TPO (thermoplastic olefin), in particular PP (polypropylene), polyacetal, in particular POM (polyoxymethylene), nylon, polyester, acrylic and polysulfone.

[0073] The translucent layer 5 of the skin 1 according to the invention comprises at least one first portion 8 configured to be placed in front of a light source 9 and to transmit the visible light generated by the light source from its inner surface 6 to its outer surface 7. The light source 9 is preferably adhered to the inner surface 6 of the translucent layer 5. Figure 3 In the embodiment, the translucent operating element 10 is additionally arranged between the light source 9 and the translucent layer 5 .

[0074] In order to adhere the light source 9 or the light source 9 combined with the operating element 10 (when they form one component) to the translucent layer 5, the light source 9 can be adhered to the translucent layer 5 by an adhesive, or the light source 9 can be attached to the translucent layer 5 when the material of the translucent layer 5 has not yet been completely cured during the process of manufacturing the translucent layer 5. It is also possible to attach the light source 9 to the base layer 3 and overmold the light source 9 together with the base layer 3 using a liquid material for manufacturing the translucent layer 5.

[0075] exist Figure 3 In the embodiment shown, the light source 9 is adhered to the translucent layer 5 via an internal elastic layer 11, which is produced against the inner surface of the translucent layer 5. The internal elastic layer 11 can have the same composition as the above-mentioned translucent layer 5 and can be manufactured in the same way as the above-mentioned translucent layer 5. In particular, both the layer 5 and the layer 11 can be manufactured in the manner disclosed in WO 2007 / 137623. The translucent layer 5 is preferably manufactured by applying a first curable polyurethane composition to the mold surface, and the internal elastic layer 11 is produced by applying a second curable polyurethane composition to the back of the translucent layer 5.

[0076] Figure 1 The decorative part 2 shown is an instrument panel. The instrument panel 2 comprises an elastic skin 1 which comprises openings for integrating functional elements such as instrument operating panels in the skin 1. The skin 1 also comprises an area in which a component comprising a combination of operating elements 10 and light sources 9 is integrated on the back of the skin so that they are not visible if the light sources 9 are not powered. The operating elements 10 and the light sources 9 can be arranged on an electronic printed foil 12 having a tail extending out of the decorative part 2 so that the operating elements 10 and the light sources 9 can be connected to a controller.

[0077] In order to avoid deformation of the integrated area when the product is exposed to different ambient temperatures, the integrated printed foil preferably has a shrinkage coefficient similar to that of the elastic skin and / or the E modulus (Young's modulus) should be the same as or smaller than the E modulus of the elastic layer. Printed foils of TPU material are very suitable for use in combination with elastic materials.

[0078] It is already foreseeable that electronic printed foils are used for electronic surface mounted devices such as LEDs, tactile actuators, coils for contactless charging, RFID readers, antennas, etc. Printed foils can also serve as OLED displays.

[0079] The first operating element 10 can be powered by different light sources 9 so that the position of the operating element 10 becomes clearly visible. It includes an on / off switch formed by a translucent pressure sensor 13 with an operating surface 14. The light source 9 behind the translucent pressure sensor 13 includes two opposite LEDs 15A and LED 15B. The space between the LEDs is filled with a light-conducting material 16, which diffuses the light of the LEDs in different directions to produce a uniform illumination of the first part 8 of the translucent skin layer 5. In addition, the operating element 10 can be completely or partially covered by a filter that filters out certain wavelengths, for example, to display a color image. Such filters also form part of the light source 9 because they determine the wavelength of the light provided by the light source 9 to the inner surface 6 of the translucent layer 5. Once the pressure sensor 13 is initially driven, the LED 15A and LED 15B are powered to obtain a visual indication of the actuation of the operating element 10 and a clearer view on the position of the first operating element 10. In addition, the light sources 9 of the other hidden operating elements 10 can be energized when the first operating element 10 is actuated, so that they become visible or more clearly visible to the user.

[0080] In order to indicate the position of the first operating element 10 when its light source 9 is not energized, the first portion 8 of the translucent skin layer 5 preferably has a first surface texture different from a second surface texture, ie a surface texture surrounding said first portion.

[0081] Typically, the second surface texture is present on a major portion of the skin surface. This second surface texture may be, for example, a leather texture or any other texture used for decorative parts. This leather texture is already present on the Figure 4 It is illustrated on a larger microscopic scale in Figure 1. It has fairly deep valleys and fairly high peaks, and the surface forming the peaks and valleys is also fairly rough. A surface with this texture is fairly matte.

[0082] like Figure 4 As shown, the first surface texture, i.e. the surface texture of the first portion 8 of the translucent skin layer 5, is preferably smoother than the second surface texture. Thus, the surface of the first portion 8 can be clearly distinguished from the surrounding portion of the skin layer 5, also because it has a higher gloss than the surface of the surrounding skin area.

[0083] The first surface texture may be produced against a completely smooth mould surface, ie against a non-textured mould surface which may even be polished.The second texture is produced on a textured area of ​​the mould surface.

[0084] In order to indicate the position of the first operating element 10 even more clearly without illumination, a surface relief is provided on the outer surface 7 of the first portion 8 of the translucent layer 5. This surface relief is formed by a surface relief element comprising a central icon 17 surrounded by several circles of dots 18, which indicates an on / off switch function, which form not only a clear visual indication of the position of the first operating element 10, but also a clear tactile indication of the position of the first operating element 10. The dots 18 are actually raised dots similar to Braille, but they are even larger, so that an inexperienced user can also feel them easily. Within the circular icon 17, the surface of the skin is completely smooth, so that the user can clearly feel the recessed area within the circular icon 17 to indicate where he must push to actuate the first operating element 10.

[0085] In the absence of the light source 9, or when the light source is not powered, the surface relief on the first portion 8 of the translucent layer 5 can only be seen when there is sufficient ambient light (e.g. daylight). According to the invention, the surface relief should also be visible when there is insufficient ambient light. Therefore, the surface relief on the first portion 8 of the translucent layer 5 is configured to produce an image on the first portion 8 of the translucent layer 5 by visible light, which is generated by the light source 9 and transmitted through the translucent layer 5 from the inner surface 6 of the translucent layer to its outer surface 7. Figures 2 to 4 The image produced by the surface relief shown is shown in Figure 6 middle.

[0086] from Figure 6 It can be clearly seen from the pictures shown that the light source 9 not only makes the image visible in the dark, but also increases the visibility of the image during the day.

[0087] According to the present invention, it has been found that the average spectral attenuation coefficient α of the colored plastic material of the semi-transparent layer 5 can be obtained by considering the thickness difference caused by the surface irregularities and the average spectral attenuation coefficient α of the colored plastic material of the semi-transparent layer 5. av to obtain the desired image.

[0088] The inventors have conducted tests to determine the effect of the thickness of a semi-transparent layer on its light transmittance. The tests showed an exponential relationship between the layer thickness and the light transmittance through the layer. Light transmittance is the ratio between illumination, i.e., the luminous flux (in lux) incident on one surface of the semi-transparent layer, and luminosity, i.e., the luminous flux (in lux) emitted from another surface of the semi-transparent layer. The inventors have found that the surface relief should preferably reduce the light transmittance of the second thicker area to at least 50% less than the light transmittance of the first thicker area to produce a clearly visible contrast between the different areas, and the greater the difference in light transmittance, the better the surface relief element can be seen.

[0089] exist Figures 2 to 4 In the embodiment shown, when the light source 9 is powered on, Figure 6 In the image shown, the first portion 8 of the translucent skin layer 5 includes at least one first area 19, wherein the thickness of the translucent layer 5 is equal to or less than the first thickness d1. In this embodiment, the first area 19 has a smooth surface and has a thickness d1 of about 0.55 mm. However, the first area may show some texture or roughness, in which case the surface of the translucent layer having valleys of smaller thickness is also included in the first area. Due to the surface unevenness, the first portion 8 of the translucent skin layer 5 also includes at least one second area 20, wherein the thickness of the translucent layer 5 is equal to or greater than the second thickness d2. Figures 2 to 4 In the embodiment of the invention, the central icon 17 and the dot 18 have a height h of about 0.17 mm, so that at the top position of these surface relief elements, the translucent layer 5 has a thickness of about 0.72 mm. Since the dot 18 is dome-shaped, only a small area of ​​the first portion 8 of the translucent skin layer 5 has such a large thickness. Therefore, the second area 20 is defined as the area where the thickness of the translucent layer 5 is equal to or greater than the second thickness d2, for example equal to 0.70 mm.

[0090] According to the present invention, the difference in thickness between the region 19 and the region 20 on the first portion 8 of the translucent layer 5 should be visually distinguishable, i.e., the difference between the first thickness d1 and the second thickness d2 should be at least greater than 0.08 mm, but less than 3.0 mm. Therefore, the height h of the icons 17 and the dots 18 should be at least greater than 0.08 mm, or preferably even at least greater than 0.10 mm.

[0091] The reduction in light transmittance resulting from a greater thickness d2 compared to d1 depends not only on the thickness difference d2-d1 but also on the average spectral attenuation coefficient α av According to the present invention, the average attenuation coefficient should be greater than 1 mm -1 , or preferably even greater than 2 mm -1 Or more preferably greater than 3mm -1 Or most preferably greater than 4mm -1 or greater than 5mm -1 A larger average attenuation coefficient can indeed achieve the same reduction in light transmittance with a smaller thickness difference d2-d1 of the semi-transparent layer 5. On the other hand, the average spectral attenuation coefficient α av Should be less than 25mm -1 , or preferably less than 20 mm -1 or more preferably less than 15 mm -1 or most preferably less than 10 mm -1In this way, when a too strong light source is not required, the thickness d1 of the first thin area 19 can still be large enough to provide the translucent skin layer 5 with the required mechanical properties.

[0092] Average spectral attenuation coefficient α av It is determined based on the transmittance of a film (sheet) of a colored plastic material having a uniform thickness of a semi-transparent layer 5 equal to said first thickness d1. EN ISO 13468-2:2006 Part 2 discloses how to measure the spectral transmittance T1(λ), ​​i.e. the total transmittance of monochromatic illumination of a given wavelength λ at intervals of 5 nm over the entire visible wavelength range, i.e. from 380 nm to 780 nm.

[0093] According to the present invention, the formula (I) is then used: The spectral attenuation coefficient is measured for each wavelength λ.

[0094] Then the average spectral attenuation coefficient α av It can be determined as the mathematical average of these different spectral attenuation coefficients α(λ).

[0095] Then the average spectral attenuation coefficient α av can be calculated over the entire visible wavelength range. This is particularly true when the light source 9 behind the first portion 8 of the semitransparent layer 5 emits white light, i.e. light comprising all wavelengths between 380 nm and 780 nm. However, when the light source 9 emits light comprising a narrower wavelength range, the average spectral attenuation coefficient α av Preferably, the measurement should be made within this narrow wavelength range. If two or more light sources 9 emitting light comprising different wavelength ranges are arranged behind the semi-transparent layer 5, preferably different average spectral attenuation coefficients α should be measured. av , ie an average value in different wavelength ranges, so that according to the invention preferably images of all different colors are produced.

[0096] In addition to the above selection of the range of the thickness difference d2-d1 and the range of the average spectral attenuation coefficient measured over the wavelength range emitted by the light source (or multiple light sources), another requirement that must be met is that α av and / or d2-d1 should be large enough so that α av (d2-d1)>-lna, where a is equal to 0.50 (lna is the log of a e value or the natural logarithm of a).

[0097] It is found that the transmittance T1 of a film (sheet) of a translucent plastic material with a thickness of d1 is defined by the following formula: When , the transmittance T2 of the film (sheet) of translucent plastic material having a greater thickness d2 at least substantially corresponds to the value obtained by the following formula: or

[0098] When a is equal to 0.50, the transmittance of the second thicker area 20 is therefore at least about 50% less than the transmittance of the first thinner area 19. This allows the second area 20 to be visually clearly distinguishable from the first area 19 when the light source 9 is powered. Preferably, a greater contrast between the first area 19 and the second area 20 is obtained by reducing the a value to 0.45, preferably 0.40, more preferably 0.35, most preferably 0.30. For these values ​​of a, the reduction in the transmittance of the thicker area 20 substantially corresponds to a reduction of 55%, 60%, 65% and 70%, respectively.

[0099] As mentioned above, in Figures 2 to 4 In the embodiment shown, the Figure 6 In the image shown, the thickness d1 of the first thinner area 19 is equal to about 0.55 mm, while the thickness d2 of the second thicker area 20 is equal to 0.70 mm (or locally even slightly greater up to 0.72 mm). The pigmented translucent polyurethane material of this translucent skin layer has a thickness of about 6.9 mm -1 The average spectral attenuation coefficient α measured over the entire visible wavelength range av The transmittance T2 is therefore at least about 64% smaller than the transmittance T1 (about 69% smaller for a thickness difference of 0.17 mm), as shown in FIG. Figure 6 As shown, this creates a clear visual distinction between the first thinner region 19 and the second thicker region 20 .

[0100] According to the formula It can be calculated that the transmittance of the first thinner region 19 is equal to about 0.022, or in other words, equal to about 2.2%. Figure 6 As shown in Figure 1, an image produced by a 1500 lux light source can be clearly seen in a dark or slightly illuminated space, but is not easily seen in daylight. When less pigment is added to the pigmented plastic material, the average spectral attenuation coefficient of the material is reduced to 6.2 mm -1 , corresponding to a transmittance of about 0.033, the image can be seen better in a well-lit space, and even in full daylight the image can be seen, albeit less clearly.

[0101] exist Figures 2 to 4In the embodiment shown, the relief elements creating the surface relief, i.e. the central icon 17 and the dots 18, provide a second thicker area 20 of the first portion 8 of the translucent layer 5. Alternatively, the translucent layer 5 can be made thicker and the surface relief elements 17 and 18 can be formed by depressions in the outer surface 7 of the translucent layer 5, wherein these depressions in the outer surface 7 of the translucent layer 5 form the first thinner area 19 of the translucent skin layer 5. In this way, the surface relief elements 17 and 18 will become visible as lighter areas on a darker background.

[0102] When the translucent layer 5 is produced against the surface of a rigid component containing the light source 9 and any operating elements 10, a surface relief can also be formed on the inner surface 6 of the translucent layer 5. In this way, due to the difference in transmittance again produced by the surface relief, an image will also be obtained on the outer surface 7 of the translucent layer 5 when the light source 9 is powered on. The negative side of the surface relief can be arranged on the surface of the light source directly facing the translucent layer, and the translucent layer can be produced, for example, by partially against that surface of the light source with a reaction overmolding process. It is also possible to provide surface relief on both the inner surface 6 and the outer surface 7 of the translucent layer 5.

[0103] Due to the fact that the semi-transparent layer 5 is made of a colored material having said average spectral attenuation coefficient, it is also possible to provide a flat screen display on the back side of the semi-transparent layer 5. Figure 1 and Figure 5 Such a flat screen display 21 is schematically shown in FIG. The flat screen display shown comprises a flexible OLED screen 21 adhered to the inner surface 6 of the second portion 22 of the translucent layer 5. Due to the relatively small thickness of the translucent layer 5 and its relatively small attenuation coefficient, the image produced by the flat screen display 21 can be seen through the translucent layer 5.

[0104] The outer surface 7 of the second portion 22 of the translucent layer 5 is preferably completely smooth, or it may show some surface texture or roughness to make it less shiny and better match the surrounding surface area so that it is less visible when the display 21 is not powered.

[0105] Preferably, the inner surface 6 and the outer surface 7 of the second portion 22 of the translucent layer 5 have a completely smooth surface texture or a surface texture having a Pt value measured according to DIN EN ISO 4287:1998, the Pt value being in mm and satisfying the following formula (III): wherein b is greater than 0.50, preferably greater than 0.60, more preferably greater than 0.70, and wherein the average spectral attenuation coefficient (α av ) is preferably measured for any visible light wavelength range emitted by a flat screen display.

[0106] Thus, the difference in light transmittance between the peaks and valleys of the texture is less than about 50%, or preferably less than 40% or less than 30%. Locally, relief elements may be provided in the second portion 22 of the translucent layer 5 to provide an additional image thereon in front of the image produced by the flat screen display 21.

[0107] like Figure 3 and Figure 5 As shown, different light sources 9 and flat screen display 21 are preferably embedded between the translucent layer 5 and the inner elastic layer 11. Therefore, even when the light source 9 or the flat screen display 21 themselves are not attached to the translucent layer 5, the light source 9 or the flat screen display 21 is adhered to the translucent layer 5 via the inner elastic layer 11.

Claims

1. A skin (1) for a vehicle interior trim component (2), the skin (1) comprising at least a translucent elastic layer (5) made of a colored plastic material, the translucent elastic layer (5) having an outer surface (7) and an inner surface (6) opposite to the outer surface (7), the translucent elastic layer (5) comprising at least one first portion (8), the first portion being configured to be located in front of a light source (9) and to transmit visible light generated by the light source (9) from the inner surface (6) to the outer surface (7), It is characterized in that The first portion (8) of the translucent elastic layer (5) comprises surface relief on the outer surface (7) and / or the inner surface (6) thereof so as to produce an image on the first portion (8) when the visible light is transmitted through the first portion (8) of the translucent elastic layer (5), the surface relief forming at least one first region (19) and at least one second region (20), the thickness of the translucent elastic layer (5) in the first region is less than or equal to a first thickness (d1), the thickness of the translucent elastic layer (5) in the second region is greater than or equal to a second thickness (d2), the second thickness (d2) is greater than the first thickness (d1), the difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is greater than 0.08 mm but less than 3.0 mm, and The colored plastic material has an average spectral attenuation coefficient (α av ), the average spectral attenuation coefficient is the average value of the spectral attenuation coefficient (α(λ)) measured at different wavelengths (λ) at fixed intervals within the visible light wavelength range by the following formula (I): in: d1 = said first thickness; and T1(λ)=spectral transmittance at said wavelength (λ) of a film of said colored plastic material having a uniform thickness equal to said first thickness (d1), measured according to EN ISO 13468-2:2006, part 2, The average spectral attenuation coefficient (α av ) included in 1.0mm -1 and 25mm -1 and is related to the difference (d2-d1) between the first thickness (d1) and the second thickness (d2) according to the following formula (II): a av (d2-d1)>-ln α(II) in: a＝0.50。 2. The skin according to claim 1, characterized in that The fixed interval is 5 nm.

3. The skin according to claim 1, characterized in that: In formula (II), a is equal to 0.

45.

4. The skin according to claim 1, characterized in that In formula (II), a is equal to 0.

40.

5. The skin according to claim 1, characterized in that: In formula (II), a is equal to 0.

35.

6. The skin according to claim 1, characterized in that In formula (II), a is equal to 0.

30.

7. The skin according to any one of claims 1 to 6, characterized in that A difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is greater than 0.10 mm.

8. The skin according to any one of claims 1 to 6, characterized in that A difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is less than 2.0 mm.

9. The skin according to any one of claims 1 to 6, characterized in that A difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is less than 1.5 mm.

10. The skin according to any one of claims 1 to 6, characterized in that A difference (d2-d1) between the first thickness (d1) and the second thickness (d2) is less than 1.0 mm.

11. The skin according to any one of claims 1 to 6, characterized in that The average spectral attenuation coefficient (α av ) greater than 2.0 mm -1 .

12. The skin according to any one of claims 1 to 6, characterized in that The average spectral attenuation coefficient (α av ) greater than 3.0 mm -1 .

13. The skin according to any one of claims 1 to 6, characterized in that The average spectral attenuation coefficient (α av ) greater than 4.0 mm -1 .

14. The skin according to any one of claims 1 to 6, characterized in that The average spectral attenuation coefficient (α av ) greater than 5.0 mm -1 .

15. The skin according to any one of claims 1 to 6, characterized in that The average spectral attenuation coefficient (α av ) less than 20.0mm -1 .

16. The skin according to any one of claims 1 to 6, characterized in that The average spectral attenuation coefficient (α av ) less than 15.0mm -1 .

17. The skin according to any one of claims 1 to 6, characterized in that The average spectral attenuation coefficient (α av ) less than 10.0mm -1 .

18. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness of less than 2.0 mm.

19. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness of less than 1.5 mm.

20. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness of less than 1.2 mm.

21. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness of less than 1.0 mm.

22. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness greater than 0.2 mm.

23. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness greater than 0.3 mm.

24. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness greater than 0.4 mm.

25. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) has an average thickness greater than 0.5 mm.

26. The skin according to any one of claims 1 to 6, characterized in that The visible light wavelength range has a width of at least 50 nm.

27. The skin according to any one of claims 1 to 6, characterized in that The visible light wavelength range has a width of at least 75 nm.

28. The skin according to any one of claims 1 to 6, characterized in that The visible light wavelength range has a width of at least 150 nm.

29. The skin according to any one of claims 1 to 6, characterized in that The visible light wavelength range has a width of at least 300 nm.

30. The skin according to claim 26, characterized in that The visible light wavelength range is from 380 nm to 780 nm.

31. The skin according to any one of claims 1 to 6, characterized in that The first portion (8) of the translucent elastic layer (5) comprises surface relief on the outer surface (7) thereof.

32. The skin according to any one of claims 1 to 6, characterized in that The skin (1) comprises at least one light source (9) which is adhered to the inner surface (6) of the first portion (8) of the translucent elastic layer (5) and is configured to emit visible light having a predetermined wavelength range, the visible light wavelength range corresponding to the predetermined wavelength range.

33. The skin according to claim 32, characterized in that The skin (1) comprises an inner elastic layer (11) adhered to the inner surface (6) of the translucent elastic layer (5), and the light source (9) is embedded between the translucent elastic layer (5) and the inner elastic layer (11).

34. The skin according to claim 33, characterized in that The light source (9) comprises at least one LED (15A, 15B) which is embedded between the translucent elastic layer (5) and the internal elastic layer (11).

35. The skin according to claim 34, characterized in that The LED is selected from bare LEDs.

36. The skin according to any one of claims 1 to 6, characterized in that The skin (1) comprises a flat screen display (21) adhered to an inner surface (6) of a second portion (22) of a translucent elastic layer (5), the second portion (22) being configured to transmit visible light generated by the flat screen display (21) from the inner surface (6) to the outer surface (7).

37. The skin according to claim 36, characterized in that The flat screen display is selected from LED screens.

38. The skin according to claim 36, characterized in that The flat screen display is selected from OLED screens.

39. The skin according to claim 36, characterized in that The inner surface (6) and the outer surface (7) of the second portion (22) of the translucent elastic layer (5) have a completely smooth surface texture or a surface texture having a Pt value measured according to DIN EN ISO 4287:1998, the Pt value being in mm and satisfying the following formula (III): Where b is greater than 0.

50.

40. The skin according to claim 39, characterized in that b is greater than 0.

60.

41. The skin according to claim 39, characterized in that b is greater than 0.

70.

42. The skin according to claim 36, characterized in that The skin (1) comprises an inner elastic layer (11) adhered to the inner surface (6) of the translucent elastic layer (5), the flat screen display (21) being embedded between the translucent elastic layer (5) and the inner elastic layer (11).

Images