Multifunctional composite structure and production method thereof

Abstract

The present invention provides a composite structure comprising a light-transmitting layer (1) having a light transmittance of 1 to 50%, an opaque layer (2) comprising a light-transmitting region (6), and a touch sensor region (5) at least partially arranged in, above or below the light-transmitting region of the layer (2). The present invention also provides a method for producing the composite structure. The composite structure can be used to replace conventional buttons in motor vehicles.

Description

Technical Field

[0001] The present invention relates to a composite structure comprising a light-transmitting layer 1 having a light transmittance of 1 to 50%, an opaque layer 2 comprising a light-transmitting region 6, and a touch sensor region 5 at least partially arranged in, above or below the light-transmitting region of the layer 2. The present invention also provides a method for producing the composite structure. The composite structure can be used to replace conventional buttons in motor vehicles. Background Art

[0002] EP 3 088 156 A1 describes a method for producing an illuminable accessory area of ​​a motor vehicle, wherein a light-transmitting foil having a masking layer which is opaque except for at least one transmission area is coated with a design which allows light to pass only in a predetermined proportion of the foil. The invention has the advantage that a foil is provided which is post-injected with a carrier in a coated state.

[0003] EP 3 053 778 A1 describes a decorative component comprising a light-emitting support made of a lighting device, the lighting device comprising a distributed light source consisting of at least one LED and a light guide, and a support supporting the component and connecting the component to the interior of the vehicle; and a decorative cover with an opaque appearance, the cover also comprising a mask allowing a pattern to be defined in a clear manner.

[0004] EP 3 051 022 A1 relates to an artificial leather comprising a textile carrier material, at least one light-transmitting layer structure based on polyurethane or polyvinyl chloride arranged on and connected to the textile carrier material, and a surface finish on the layer structure, wherein the artificial leather has a low visible light transmittance.

[0005] EP 3 072 743 A1 relates to an interior lining component for a motor vehicle, comprising a light-transmitting support having a front and a rear, a light-transmitting cover selected from a TPO, TPU, TPE, PO or PVC film located on the front of the carrier component, and a light source located at the rear of the support, wherein the combination of the carrier and the light-transmitting cover has a low transmittance in the visible light wavelength range.

[0006] These prior art documents do not disclose lining components having functions other than lighting.

[0007] On the other hand, WO 2015188955 A1 discloses a flexible sheet made of a conductive polymer material, which has a functional surface area designed in the form of a switch, a sensor or an operating element.

[0008] WO 2016198969 A1 discloses a flexible textile structure with sensing and lighting functions while retaining the main features of typical textiles, such as comfort, seamlessness and mechanical flexibility. Sensing applications include directly printed self-capacitive sensors, knitted textile sensors, and bulk capacitance sensors for temperature / humidity integrated directly on textiles. Lighting applications for decoration and signage include electroluminescent sensing devices and hybrid sensors using surface mount light emitting diodes (SMD LEDs) and printed self-capacitive sensors.

[0009] These prior art documents do not disclose the use of a light-transmitting layer to conceal functional areas. Summary of the invention

[0010] Problems to be solved by the present invention

[0011] The prior art does not disclose the situation that conventional buttons are replaced by systems using lining components. In particular, the prior art does not disclose the following system using a touch sensor, wherein the area including the touch sensor and other functional components is covered by a layer with low light transmittance.

[0012] The problem underlying the invention is therefore to provide a structure having a seamless surface and comprising a touch sensor which can be hidden unless illuminated, and to provide an improved method for producing such a structure. The structure can be used as a component replacing conventional buttons in motor vehicles.

[0013] Summary of the Invention

[0014] The problem underlying the invention is solved by providing a composite structure and a production method as defined in the claims.

[0015] The subject matter of this application is as follows.

[0016] [1] A composite structure comprising a light-transmitting layer 1 having a light transmittance of 1 to 50%, an opaque layer 2 including a light-transmitting region 6, and a touch sensor region 5 at least partially arranged within, above or below the light-transmitting region 6 of the layer 2.

[0017] In one embodiment of [1], the composite structure includes a light-transmitting layer 1 with a transmittance of 1 to 30%, wherein the light-transmitting layer 1 covers an opaque layer 2 and a touch sensor area 5, wherein the opaque layer 2 includes a light-transmitting area 6, and the touch sensor area 5 is at least partially arranged in, above or below the light-transmitting area 6 of the opaque layer 2.

[0018] The following embodiment of [1] is preferred: a composite structure comprising a light-transmitting layer 1 having a light transmittance of 1 to 50%, an opaque layer 2 comprising a light-transmitting area 6, and a touch sensor 11 arranged completely within or below the opaque area of ​​layer 2.

[0019] The following embodiment of [1] is more preferred: a composite structure comprising a light-transmitting layer 1 having a light transmittance of 1 to 50%, an opaque layer 2 comprising a light-transmitting area 6, and a touch sensor area 5, characterized in that the touch sensor area 5 comprises a touch sensor 11 completely arranged under the opaque area of ​​layer 2 and a light-transmitting area 12 at least partially arranged under the light-transmitting area 6 of layer 2.

[0020] [2] The composite structure according to [1], wherein the opaque layer 2 including the light-transmitting region 6 is a mask layer.

[0021] [3] The composite structure according to [1] or [2], comprising a sensor layer 3, wherein the sensor layer 3 comprises a touch sensor area 5 and an electrical conductor connected to at least the touch sensor area 5.

[0022] Preferably, the composite structure comprises in sequence a light-transmitting layer 1 , an opaque layer 2 comprising a light-transmitting area 6 , and a sensor layer 3 comprising a touch sensor area 5 and an electrical conductor at least connected to the touch sensor area 5 .

[0023] [4] A composite structure according to any one of [1] to [3], wherein the touch sensor area 5 includes a touch sensor 11 arranged completely below the opaque area of ​​layer 2 and a translucent area 12 arranged at least partially below the translucent area 6 of layer 2.

[0024] [5] A composite structure according to any one of [1] to [4], comprising, in sequence, a light-transmitting layer 1, an opaque layer 2 including a light-transmitting region 6, an optional sensor layer 3 and a support layer, wherein the support layer is light-transmitting or at least partially light-transmitting.

[0025] [6] A composite structure according to any one of [1] to [5], comprising a light source arranged in or attached to at least one of the following layers: an opaque layer 2 comprising a light-transmitting area 6, a light-transmitting sensor layer 3, and a support layer.

[0026] [7] A composite structure according to any one of [1] to [6], comprising a soft layer, which is included in the light-transmitting layer 1 below one or more dense layers 7, or is arranged between the light-transmitting layer 1 and layer 2, or is arranged between the support layer and the opaque layer 2 or, if layer 3 is present, between layer 3.

[0027] [8] The composite structure according to any one of [1] to [7] can be obtained by a method comprising the following steps: step (i), applying an opaque layer 2 including a light-transmitting area 6 on a light-transmitting layer 1; and subsequently step (ii), applying a touch sensor area 5 or a sensor layer 3 including a touch sensor area 5 on the light-transmitting layer 1.

[0028] [9] A composite structure according to any one of [1] to [8], wherein the light-transmitting layer 1 is the front side of the composite structure and is selected to make other elements of the composite structure invisible in the absence of light emitted from a light source arranged in the composite structure or at the back side of the composite structure.

[0029]

[10] A composite structure according to [9], wherein the light-transmitting element is selected to allow transmission of visible light emitted from a light source arranged in the composite structure or at the back side of the composite structure, and the opaque area is selected to prohibit transmission of visible light emitted from the light source arranged in the composite structure or at the back side of the composite structure.

[0030]

[11] A method for producing a composite structure as described in any one of [1] to

[10] , comprising: step (i), applying an opaque layer 2 including a light-transmitting area 6 on a light-transmitting layer 1; and step (ii), applying a touch sensor area 5 or a sensor layer 3 including a touch sensor area 5 on the light-transmitting layer 1.

[0031]

[12] The method according to

[11] , wherein step (ii) is performed after step (i).

[0032]

[13] The method according to

[11] or

[12] , wherein steps (i) and (ii) are both printing steps selected from screen printing and inkjet printing.

[0033]

[14] The method according to any one of

[11] to

[13] , wherein step (i) is printing an opaque masking layer, and step (ii) is printing the sensor layer 3. In a preferred embodiment, the sensor layer 3 is printed on the same side of the light-transmitting layer 1 as that on which the opaque masking layer is printed.

[0034]

[15] The method according to

[11] comprises: step (a), applying an opaque layer 2 including a light-transmitting area on the sensor layer 3; and step (b), applying the modified sensor layer 3 obtained in step (a) on the light-transmitting layer 1.

[0035] Advantages of the Invention

[0036] The use of a touch sensor in the composite structure of the present invention enables the replacement of conventional buttons, thereby obtaining a structure with a seamless surface.

[0037] The composite structure is flexible and soft and may have a texture. The texture may be geometric or may be designed to mimic natural leather.

[0038] The composite structure may have properties that render the touch sensor invisible unless the structure is illuminated. Thus, the sensor may be "light-free".

[0039] These properties of the composite structures of the present invention allow for new and innovative design options. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1A The composite structure of the invention is shown, which comprises a light-transmitting layer 1 and a touch sensor area 5 arranged in a light-transmitting area 6 of an opaque layer 2 .

[0041] Figure 1B A composite structure of the invention is shown, comprising a light-transmitting layer 1 and a touch sensor area 5 arranged above a light-transmitting area 6 of an opaque layer 2 .

[0042] Figure 1C The composite structure of the invention is shown, comprising a light-transmitting layer 1 and a touch sensor area 5 arranged below a light-transmitting area 6 of an opaque layer 2 .

[0043] Figures 2A to 2C The composite structure of the present invention is shown, which comprises a light-transmitting layer 1, an opaque layer 2 comprising a light-transmitting area 6, and a sensor layer 3 comprising a touch sensor area. The layer 2 may comprise the light-transmitting area 6 as a layer part ( Figure 2A ). Layer 2 may be a mask including a light-transmitting region 6 which is a void region next to an opaque portion ( Figure 2B and 2C ).

[0044] Figures 3A to 3C The composite structure of the present invention is shown, which includes a light-transmitting layer 1, an opaque layer 2 including a light-transmitting area 6, and a sensor layer 3 including a touch sensor area 5. In this embodiment, the touch sensor 11 surrounds the light-transmitting area 12. The top view of the touch sensor area 5 is also shown in FIG. Figure 5 ). The layer 2 may include a light-transmitting region 6 as a layer portion ( Figure 3A ). Layer 2 may be a mask comprising light-transmitting regions 6, which are void regions next to the opaque portions ( Figure 3B and 3C ).

[0045] Figure 4 The composite structure of the invention is shown comprising a lacquer layer 9, a light-transmitting layer 1 comprising three dense layers 7 and a soft layer 8, an opaque layer 2 comprising light-transmitting areas 6 and a sensor layer 3 comprising a touch sensor area and other electrical and electronic components.

[0046] Figure 5 An exploded view of a composite structure of the invention is shown, the composite structure comprising a light-transmissive TPU foil 1 , an opaque screen-printed mask 2 and a sensor layer 3 comprising a capacitive screen-printed touch sensor area 5 .

[0047] Figure 6 yes Figure 5 A detailed view of the sensor layer 3 of the composite structure is shown. The sensor layer 3 comprises a plurality of sensors to activate different functions.

[0048] Figure 7 Schematically shows the production Figure 5 The sequence of method steps for the composite structure shown. In a first step, an opaque mask is screen printed on the light-transmitting foil, and in a second step, a capacitive sensor is screen printed on the mask.

[0049] Fig. 8A and 8B Shows Figure 5 The matte hiding properties of the composite structure shown. Fig. 8A The backlight is deactivated in Figure 8B , the backlight is activated.

[0050] Fig.9A and 9B Two screen printing techniques are shown that can be used to screen print structures of the composite structure of the present invention, such as a screen printed mask and a screen printed sensor. DETAILED DESCRIPTION

[0051] The total thickness of the composite structure of the present invention is preferably 50 to 20,000 μm, more preferably 100 to 5,000 μm.

[0052] The thickness of the light-transmitting layer 1 is preferably 30 to 3000 μm, more preferably 80 to 1000 μm. The thickness of the layer 2 is preferably 1 to 100 μm, more preferably 2 to 20 μm. The thickness of the touch sensor area 5 is preferably 0.5 to 30 μm, more preferably 1 to 10 μm. The thickness of the sensor layer 3 is preferably 1 to 1000 μm, more preferably 10 to 500 μm. The thickness of the support layer is preferably 10 to 10000 μm, more preferably 100 to 5000 μm.

[0053] The composite structure comprises a layer structure and is itself a layer structure. In the present invention, the plane of a layer of the composite structure is sometimes referred to as a "layer plane".

[0054] For each layer structure described in the present invention, the term "layer" refers to a structure defined by a length x, a width y and a depth or thickness z. In a layer, the values ​​of x and y are at least 5 times, preferably at least 10 times or at least 20 times the value of z, respectively. The plane of the layer is defined by x and y. In the composite structure of the present invention, the planes of the layers are parallel to each other, and the values ​​of x and y are preferably at least 1 cm, more preferably at least 2 cm, and even more preferably at least 5 cm, respectively.

[0055] The composite structure can be defined by its visible side, i.e. the upper side of the light-transmitting layer 1, which side may have a texture and / or a paint layer 9. This side is also referred to as the A side. The bottom side is referred to as the B side. These designations apply to all layers of the composite structure. This means that the side facing the light-transmitting layer is the A side of the layer, and its back side is the B side of the layer. Directions within the same layer plane are referred to as horizontal directions, and directions from one layer plane to another layer plane, in particular directions perpendicular to the layer planes, are referred to as vertical directions within the composite structure.

[0056] The expressions “above” and “below” relate to a position perpendicular to the layer plane. For example, a touch sensor region 5 arranged below or above the light-transmitting region 6 is arranged at a position perpendicular to the layer plane of the light-transmitting region.

[0057] When light is emitted from the same light source and shines on the structure, the "light-transmitting" structure allows more visible light to be transmitted compared to the "opaque" structure.

[0058] In the present invention, the meaning of the term "light-transmitting" covers the meaning of "transparent". Generally speaking, transparency refers to the physical property of allowing light to pass through a material without being scattered. Light-transmitting is a superset of transparency, allowing light to pass through and also allowing scattering. In other words, light-transmitting media allow the transmission of light, while transparent media allow not only the transmission of light but also the formation of images. Transparent materials appear clear.

[0059] Since transmittance values ​​are affected by absorption, scattering, reflection, etc., the specific transmittance values ​​of different parts in a composite structure may vary depending on the type of light source, the composition and thickness of the layers. Transmittance is also different for different wavelength ranges.

[0060] In one embodiment, the light-transmitting structure is defined as a lighting system with relatively low luminous power, such as a light source, such as a 0.5 watt LED, so that the brightness of the composite structure can be achieved in the range of 2 to 4 cd / m 2 (cd = candela) or even between 2 and 5 cd / m 2 Thus, suitable background lighting is achieved, wherein the components arranged under the light-transmitting layer 1 are not visible as long as the lighting system is deactivated. This type of lighting is also referred to as dark hidden lighting.

[0061] Different light-transmitting layers of the composite structure may have different light transmittances. For example, in the wavelength range of 400 to 700 nm, the light transmittance of the composite structure through the light-transmitting region in the vertical direction from the B side to the A side or from the light source to the A side may be 1 to 50%, preferably 1 to 30%, more preferably 2 to 20%, and even more preferably 5 to 10%.

[0062] The composite structure having the desired light transmittance includes one of the following combinations of light-transmitting elements:

[0063] - Layer 1 with layer 2 at its B side.

[0064] - Layer 1 having layer 2 and layer 3 in sequence on its B side.

[0065] - Layer 1 having, on its B side, layer 2, layer 3 and a supporting layer in sequence.

[0066] The opposite property to light transmission is opacity. The light transmittance of the opaque part of the composite structure, i.e. the part comprising the opaque area of ​​layer 2, may be less than 1%, preferably less than 0.1%, more preferably 0%. This value preferably relates to a wavelength range of 400 to 700 nm. In a preferred embodiment, the term "opaque" means that the light transmittance in the wavelength range of 400 to 700 nm is less than 1%. In any case, the light transmittance of the opaque layer is lower than the light transmittance of the light-transmitting layer 1. For example, if the light transmittance of the light-transmitting layer 1 is at least 2%, then the light transmittance of the layer included in the same composite structure and referred to as "opaque" is less than 2%.

[0067] The light transmittance of the composite structure is ultimately determined by the composite of the materials, wherein the light transmittance of the light-transmitting layer 1 can be low enough to achieve the desired characteristic of hiding other elements when the light source is deactivated, i.e., other elements are hidden by no light. When the light source is deactivated, the upper side of the composite structure has the appearance of a conventional structure, such as conventional artificial leather.

[0068] In order to achieve the property of hiding the elements arranged under the light-transmitting layer 1 , the light transmittance of the light-transmitting layer 1 in the wavelength range of 400 to 700 nm is preferably 1 to 50%, more preferably 1 to 30%, still more preferably 2 to 20% or 5 to 10%.

[0069] The light transmittance of the light-transmitting layer 1 may be significantly lower than the light transmittance of other light-transmitting elements, for example by a factor of 10 or more. The light transmittance of other light-transmitting elements may reach 100%, ie they may even be transparent.

[0070] The light-transmitting element and the light source can be adapted to each other to achieve 1 to 20 cd / m 2 , preferably 2 to 20 cd / m 2 , more preferably 2 to 10 cd / m 2 or 2 to 8cd / m 2brightness.

[0071] The light transmittance of each layer or any layer of the layer structure, i.e. the composite structure, described in the present application is determined accordingly in the following manner: Equipment: Datacolor, Model 850; Lamp: Xenon lamp. The total transmittance is measured according to the user guide provided by the manufacturer. White patches (such as The white plaque is used as an optical standard for transmittance calibration and measurement. The white plaque is placed on the front aperture plate. The sample to be tested is placed at the opening of the sphere. The wavelength λ of the maximum transmittance peak of the sample in the range of 400 to 700 nm is max The transmittance of the sample [%] is defined as 100% × (in the presence of the layer structure at λ max Transmittance value measured at λ) / (transmittance value measured at λ without layer structure max The transmittance value measured under ).

[0072] The material used for the support layer may have a high light transmittance of up to 90%. The material used for the light-transmitting layer 1 may have a light transmittance of 1 to 50%. The combination of these materials may allow the composite structure to have a light transmittance of 5 to 10%.

[0073] Whenever it is mentioned in the context of this specification that each component or element is based on a certain material or is made of a certain material, it should be understood that the corresponding material forms the main component of the component, wherein other components may also be present in small amounts. In an embodiment, the term "based on" a certain material or "made of" a certain material means that the content exceeds 50% (weight), preferably 90% (weight), and more preferably 95% (weight).

[0074] Mixtures of the listed materials with other materials may be used. In addition, additives may be used, for example, in the form of UV stabilizers to prevent corrosion and fading, dyes and pigments for designing the appearance, or foams to reduce weight.

[0075] In some examples, a graphic design, image, pattern or the like is provided in or on the composite structure. In this specification, these elements may be collectively referred to as graphics. For example, a decorative pattern or an indicative pattern may be applied. The pattern may be colored, such as red, to simplify the user's orientation, or to draw the user's attention to the illuminated area when the light source is activated.

[0076] Examples of applying the pattern are inkjet printing, screen printing, laser printing, laser etching or painting with the aid of a mask etc. Inkjet printing and screen printing are preferred.

[0077] It should be noted that these graphics can be provided on any A side or B side of any layer that is illuminated, for example any layer that overlaps with the light source. In particular, the graphics can be provided on the B side of layer 1, on the A side of touch sensor area 5, on any side of sensor layer 3, or on any side of a layer by printing the graphics onto the surface of the described side of the corresponding layer. Similar to touch sensor area 5, the graphics are arranged in the light-transmitting area of ​​layer 2, below or above it.

[0078] In the present specification, elements and components are generally described in the singular form, such as "a" component or "comprising a" component. It should be emphasized that these forms do not exclude the existence of more than one of the indicated components or elements unless otherwise specified.

[0079] In the present invention, the standards and specifications mentioned refer to the latest versions at the time of filing of this application, unless otherwise specified.

[0080] Light-transmitting layer 1

[0081] This layer may be referred to simply as "layer 1".

[0082] In the wavelength range of 400 to 700 nm, the light transmittance of the layer 1 is 1 to 50%, preferably 1 to 30%, more preferably 2 to 20%, even more preferably 5 to 10%.

[0083] In one embodiment, layer 1 covers opaque layer 2 , touch sensor area 5 and other layers and elements in the composite structure, except for lacquer layer 9 arranged on top of layer 1 and texture present on the top surface of layer 1 .

[0084] In another embodiment, layer 1 covers the touch sensor area 5 and other layers and elements in the composite structure, except for the opaque layer 2 arranged on top of layer 1, and optionally except for the paint layer and texture that may be present on top of layer 2.

[0085] The layer 1 may be a single layer or a composite layer structure. It may comprise a dense layer structure and may optionally comprise a lacquer layer 9 on one side and one or more foam layers 8 on the other side.

[0086] In the present invention, the dense layer structure includes one or more than one dense layer 7 .

[0087] Furthermore, layer 1 may be covered by a lacquer layer 9, the uppermost component at side A of layer 1, and / or may have a textured surface structure to simulate natural leather. Additives may be included in layer 1. Adhesives may be present between structures of layer 1. All these ingredients may together constitute layer 1 and have the desired light transmittance as a whole.

[0088] The additives contained in the light-transmitting layer 1 may be additives that make it resistant to ultraviolet light and / or high temperatures. Two types of light stabilizers may be used, namely ultraviolet light absorbers (UVA) and hindered amine light stabilizers (HALS). Various types of UVA are commercially available, such as benzotriazole, which provides the widest spectrum coverage. Triazines are also an option. HALS capture free radicals to maintain surface properties, such as gloss, and prevent cracking and chalking of coatings (paints). When used in combination, UVA and HALS have a synergistic effect and provide a simple formulation. With regard to thermal degradation, suitable products are, for example, benzenepropanamide, N,N'-1,6-hexanediylbis[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropanamide], antioxidants and tris(2,4-di-tert.-butylphenyl)phosphite.

[0089] If present, the lacquer layer 9 is part of the light-transmitting layer 1 and may contribute to the low light transmittance of the layer 1. This means that other layer components of the layer 1 may have a higher light transmittance than the lacquer layer.

[0090] Since the uppermost component of the layer 1 is often touched by the user, it should be selected to have high wear resistance. In particular, the paint layer 9 as the uppermost layer of the layer 1 preferably has high wear resistance.

[0091] In one embodiment, layer 1 is a single layer, such as a light-transmitting foil. It may consist of or include a film, such as a film consisting of TPO, TPU, TPE, PO, PVC or a combination thereof. Preferred materials are TPU, TPO or PVC.

[0092] In another embodiment, the layer 1 comprises one or more than one soft layer, preferably one soft layer, and a dense layer structure optionally covered by a lacquer layer 9. In particular, the layer 1 may comprise a soft layer and two or three dense layers covered by a lacquer layer 9 and having a texture. The soft layer is preferably a foam layer.

[0093] In the present invention, the soft layer has a lower Shore A hardness than the dense layer structure of the light-transmitting layer 1 .

[0094] In the present invention, the density of the dense layer is greater than 0.80 g / cm 3 The density of the foaming layer is less than 0.80g / cm 3 .

[0095] The dense layer structure of the light-transmitting layer 1 preferably comprises two or three dense layers. These layers may differ in composition, thickness, light transmittance and any other properties. The total thickness of the dense layer structure is preferably 30 to 2000 μm, more preferably 80 to 1000 μm.

[0096] The base material of layer 1 preferably has low crystallinity and low oil content in the formulation. The pigment masterbatch is selected to have the right amount of pigment and dispersing additives to ensure uniform pigment distribution and thus uniform color and light transmittance. Additives are preferably added to avoid degradation of the light transmittance effect over time due to thermal or UV aging.

[0097] The layers included in the light-transmitting layer 1 may have the following preferred thicknesses: lacquer layer 9: 1 to 50 μm, more preferably 2 to 30 μm; dense layer 7: 50 to 1000 μm, more preferably 100 to 500 μm; foam layer 8: 50 to 1000 mm, more preferably 100 to 500 mm. The preferred ranges mentioned are combined in preferred embodiments, and the more preferred ranges mentioned are combined in more preferred embodiments.

[0098] The layer 1 can be manufactured in different ways, for example, by means of extrusion, knife coating, injection molding or sintering, vacuum molding, casting or rotational molding and other known processes. The covering material can be smooth or textured to imitate, for example, natural leather. The texture can be produced before, during or after the molding process. The texture included on the light-transmitting layer to imitate natural leather can have a depth of 10 to 1000 μm, preferably 50 to 500 μm. Preferably, these materials are also UV-resistant and heat-resistant.

[0099] The above-mentioned patterns can be applied to layer 1. Furthermore, layer 1 can have structures on its A side and / or its B side, wherein the structures are produced during the shaping of the covering material or by means of subsequent processing, such as laser processing or etching.

[0100] Layer 1 is preferably flexible and soft. Preferably, layer 1 has a soft touch, for example, a Shore A hardness in the range of 60 to 80, for example about 70. The Shore A hardness mentioned in the present invention is defined in DIN 53505.

[0101] Layer 1 may contain cork particles. Preferred cork particles and methods for producing them and incorporating them into layer structures are described in EP 3 051 022 A1. These particles may be light-transmissive, opaque or fluorescent and may be contained in any of the layers 1. They may be visible or invisible when the light source is not activated.

[0102] Opaque layer 2 including light-transmitting area 6

[0103] This layer is also referred to as opaque layer 2 including light-transmitting areas or simply "layer 2".

[0104] Layer 2 includes light-transmitting areas and opaque parts. The opaque areas can be discontinuous and therefore do not have to be connected to each other. Different opaque areas can have different properties, such as thickness, light transmittance, color, etc.

[0105] The opaque area may be a large opaque area and / or a relatively thin opaque graphic, such as a letter, symbol, or frame.

[0106] Layer 2 can be a coating on another layer, such as a paint or a mask, preferably a mask. Preferably, layer 2 is a mask printed on the B side of layer 1. The printing technique can be laser printing or preferably inkjet or screen printing. The paste or ink used in the printing method preferably has high adhesion to the substrate, such as the B side of layer 1.

[0107] The light-transmitting area 6 may be a void area surrounded by an opaque portion, i.e., an area where no opaque portion, such as a mask, is arranged. In this case, the structure arranged directly at the B side of the layer 2, such as the layer 3 and / or the touch sensor area 5, is in direct contact with the layer 1 in the light-transmitting area 6 (see Figure 2B and 2C ).

[0108] Layer 2 may also be a film, preferably a film made of a polymer, applied to another layer. The opaque area may be provided by dyeing the light-transmitting film with a dye that imparts opacity to the dyed area of ​​the film. In one embodiment, the film may include a touch sensor area 5 and optionally other electrical components, such as those necessary for the touch sensor area to perform its function. This embodiment is an example of a touch sensor area 5 being arranged "in" the light-transmitting area of ​​layer 2.

[0109] In the case where the light-transmitting region 6 is not a simple void region, it may be made of the material of the layer 2 and may be a region that has not been rendered opaque, for example, by dyeing. The light transmittance of the light-transmitting region 6 is not limited and may be 1 to 100%, preferably 10 to 90%, and more preferably 50 to 90% in the wavelength range of 400 to 700 nm.

[0110] The material of layer 2 is not limited. Layer 2 can be made of a dense layer or a soft layer, such as a foam layer or any other soft material, such as a textile layer. The opaque area of ​​layer 2 can be dyed, especially in the case of a foam layer or a textile.

[0111] The material of layer 2 may be a plastisol, which is a suspension of PVC or other polymer particles in a liquid plasticizer. Plastisol flows in liquid form and can be poured into a heated mold. When heated, the plastic particles dissolve and the mixture becomes a highly viscous gel that can usually no longer be cast. After cooling, a flexible, permanently plasticized solid product is formed. Plastisols can be used as screen printing inks and are particularly useful for printing opaque graphics. Plastisol inks can be cured.

[0112] In one embodiment, layer 2 is used not only to provide the functions of opaque areas and light-transmitting areas. In particular, in the case where the touch sensor area 5 is arranged below layer 2, the material of layer 2 (preferably dyed) can be soft and can therefore contribute to the desired tactile feel of the composite structure. In this case, a soft material, such as foam or textile, must be selected so as to show suitable light transmittance and other desired properties in the undyed areas, such as low light scattering and / or visibility or invisibility of structural elements of the foam or textile when illuminated. In this embodiment, layer 1 can be made of dense layers only, i.e. without foam layers or other soft layers.

[0113] Touch sensor area 5

[0114] The touch sensor area 5 is preferably a sensor that is sensitive to changes in pressure, or temperature, or pressure and temperature. Preferably, the sensor signal can be influenced by the touch of a finger of a human user.

[0115] The function of the touch sensor area 5 may be that of a switch or a button to actuate an electrical device such as a light or a motor.

[0116] The touch sensor area 5 can be a membrane touch switch, which is a momentary electrical on / off switch for activating and deactivating a circuit. The membrane touch switch must be pressed so that its two poles are in direct contact to close the circuit. When the membrane touch switch is released, the two poles separate and the switch returns to its original open state. The membrane touch switch can be made by printing conductive silver, copper or carbon ink on a polymer foil. The membrane is applied to the first surface of the switch to obtain the membrane touch switch. Examples of commercially available membrane touch switches are ME602 (DuPont), which is a stretchable silver conductor that can withstand thermoforming and post-molding temperatures, or ME774 (DuPont), which is a UV-curable crossover dielectric that can withstand thermoforming and post-molding temperatures.

[0117] The sensor may be a capacitive sensor, preferably a layer sensor. In one embodiment, the sensor is a capacitive layer sensor.

[0118] The sensor can be functionally connected to other electrical or electronic components. For this purpose, the touch sensor area 5 includes elements that connect it to other electrical components. These elements are electrical contacts or electrical conductors. Therefore, the sensor is preferably accommodated in a sensor layer 3 that includes at least electrical conductors or contacts.

[0119] The touch sensor area 5 is adapted to be responsive to preferably 5 g (per 1 cm 2 area 5mbar) to 1000kg (per 1cm 2 The pressure difference over the area is preferably at least 0.1 K, more preferably at least 0.2 K and most preferably at least 0.5 K.

[0120] The touch sensor area 5 may be a capacitive layer sensor comprising a first conductive layer, a ferroelectric polymer and a second conductive layer in sequence.

[0121] The conductive layer may be a base electrode and a covering electrode, and may be each made of PEDOT-PSS (PEDOT:PSS: Poly(3,4-ethylenedioxythiophen)polyystyrolsulfonat), carbon, silver, aluminum, chromium, gold, or copper. A preferred example of the electrode material is PEDOT:PSS having a thickness of about 1 μm. Poly-3,4-ethylenedioxythiophene (PEDOT) is a thiophene-based conductive polymer.

[0122] The ferroelectric layer can be a copolymer PVDF-TrFE (polyvinylidene fluoride-trifluoroethylene), which can show strong piezoelectric or thermoelectric activity. (P(VDF:TrFE)=50:50 to 85:15 or 70:30 to 80:20) and has a thickness of about 1 μm. Other examples of ferroelectric polymer layers can be terpolymers of PVDF-TrFE-CFE or PVDF-TrFE-CTFE, wherein the molar ratio of PVDF:TRFE:CFE is preferably 50-75:20-40:5-10, or the molar ratio of PVDF:TRFE:CTFE is preferably 50-75:20-40:5-10. The ferroelectric polymer layer can also be a composite material containing PVDF-TrFE and 5 to 50% (by weight) of nanoparticles such as SrTiO3, PbTiO3, PbZrTiO3 or BaTiO3.

[0123] The following abbreviations are used: PVDF: polyvinylidene fluoride; TrFE: trifluoroethylene; CFE: chlorofluoroethylene.

[0124] The conductor can be copper or silver.

[0125] Additionally, conductive glue can be used if necessary.

[0126] The touch sensor area 5 is arranged in or above or below the light-transmitting area of ​​the layer 2. This means that the touch sensor area 5 can be accommodated in the light-transmitting area of ​​the layer 2.

[0127] As another alternative, the touch sensor area 5 may be arranged above the layer 2 , ie at the A side, or below, ie at the B side.

[0128] The touch sensor area 5 includes touch sensors or is composed of touch sensors. Since the touch sensor area can be composed of touch sensors, these two expressions can be used interchangeably in this specification.

[0129] In one embodiment, the touch sensor area 5 includes or consists of light-transmitting touch sensors.

[0130] In another embodiment, the touch sensor area 5 includes an optionally opaque touch sensor 11 and a light-transmitting area 12. Preferably, the optionally opaque touch sensor 11 is completely below the opaque area of ​​the layer 2, i.e., completely covered by the opaque area of ​​the layer 2, and the light-transmitting area 12 is at least partially aligned with the light-transmitting area 6 of the layer 2. In this case, the touch sensor area 5 preferably includes the light-transmitting area 12 at least partially aligned with the light-transmitting area 6 of the layer 2 and the optionally opaque touch sensor 11, which is arranged at a horizontal distance of less than 5 mm, more preferably less than 3 mm from the light-transmitting area 6 of the layer 2. Alternatively, the optionally opaque touch sensor 11 surrounds the light-transmitting area 12 at least partially aligned with the light-transmitting area 6 of the layer 2, and is arranged at a horizontal distance of less than 5 mm, more preferably less than 3 mm from the light-transmitting area 6 of the layer 2.

[0131] In the present invention, a structure, such as an area or a sensor, arranged to be "aligned with the light-transmitting area 6" means that the structure is arranged in the horizontal direction so that a light beam can pass through the composite structure through the structure and the light-transmitting area 6 of layer 2 in a direction perpendicular to the layer plane.

[0132] This means that the position of the touch sensor area is free in the vertical direction within the composite structure as long as it is aligned in the horizontal direction with the light-transmitting area of ​​the layer 2. In other words, the touch sensor area is at least partially arranged in the area transmitted by the light beam passing through the light-transmitting area 6 of the layer 2 in the vertical direction. Preferably, the touch sensor area 5 is arranged below the light-transmitting layer 1.

[0133] Therefore, the touch sensor area 5 included in the composite structure of the present invention is preferably defined as a touch sensor area 5 that is at least partially arranged in, above or below the light-transmitting area 6 of layer 2, and the touch sensor area 5 includes a touch sensor 11, which is at least partially arranged in, above or below the light-transmitting area 6 of layer 2, or the horizontal distance from the light-transmitting area 6 of layer 2 is less than 5 mm, more preferably less than 3 mm, and the touch sensor area 5 also includes a light-transmitting area 12 that is arranged at least partially aligned with the light-transmitting area 6 of layer 2.

[0134] In a preferred embodiment of the present invention, the touch sensor area 5 includes a light-transmitting element. The touch sensor area 5 may include (i) a light-transmitting touch sensor, or (ii) an optional light-transmitting touch sensor and a light-transmitting area, wherein the light-transmitting element of (i) or (ii) is at least partially aligned with the light-transmitting area 6 of the layer 2 in a direction perpendicular to the layer plane. In (ii), the light-transmitting area is preferably surrounded by the touch sensor or spaced from the touch sensor by a distance of less than 3 mm.

[0135] The touch sensor area 5 is arranged at least partially in, above or below the light-transmitting area of ​​the layer 2. Preferably, the touch sensor area 5 is in direct contact with the light-transmitting area of ​​the layer 2, which means that no other layers or materials are present between them.

[0136] Layer 2 may be a mask and the touch sensor area may be arranged below the mask. The mask may include large, continuous opaque areas, but also small, discontinuous opaque areas, such as opaque graphics or symbols. These small opaque areas may be included in other illuminated areas of layer 2 and may be arranged above the touch sensor area, for example, to attract the user's attention or simplify its orientation.

[0137] The touch sensor area 5 may be opaque or light-transmissive. It may also be light-transmissive and include less light-transmissive or opaque areas, such as graphics, to indicate its position or function to the user, for example. These graphics may be part of layer 2.

[0138] Sensor layer 3

[0139] This layer is an optional feature of the composite structure of the present invention and may be referred to simply as "Layer 3".

[0140] Layer 3 comprises a touch sensor area 5 and electrical conductors or contacts. It may be attached to or comprise elements necessary for the touch sensor area 5 to function, such as resistors, capacitors, control elements, etc. These additional elements may be arranged outside the sensor layer 3 or at least partially within the sensor layer 3.

[0141] Layer 3 can be applied to side B of layer 1 by inkjet printing, screen printing, preferably after layer 2 has been applied to side B of layer 1 .

[0142] The layer 3 may include the touch sensor area 5 and the other components mentioned in relation to the touch sensor area 5. Furthermore, the layer 3 may include a light source. Furthermore, the A side or the B side of the layer 3 may be partially covered by an opaque layer.

[0143] light source

[0144] A light source is an optional feature of the composite structure of the present invention.

[0145] The light source serves the purpose of illuminating the light-transmissive area of ​​the composite structure and indicating the position of the sensor. Thus, when the light source is activated, the light source simplifies the orientation of the user or draws the user's attention to the illuminated area.

[0146] The light source of the present invention may be a light source arranged at the B side of the composite structure. The light source may be included in the composite structure, or adhered to the B side of the support layer, and thus may be part of the composite structure of the present invention. Alternatively, the light source may be positioned to be spaced apart from the B side of the composite structure. In this case, the light source is not part of the composite structure of the present invention. In both cases, the light beam of the light source passes through the layers of the composite structure in the following order in the vertical direction: the light-transmitting area of ​​layer 4; the sensor 5 and / or the surrounding area of ​​sensor 5 in layer 3; the light-transmitting area of ​​layer 2; and layer 1. Therefore, the light-transmitting areas and elements must be aligned to allow this vertical light to be transmitted through the composite structure.

[0147] The light source may be arranged in the composite structure of the invention, for example in layer 3 or layer 4. It may overlap or not overlap the touch sensor area 5. If overlapping the touch layer 5, the light beam emitted by the light source passes through the layers of the composite structure in the vertical direction. If the light source is included in the sensor layer 3 and does not overlap the touch layer 5, the light beam emitted by the light source passes through the layer 3 in the horizontal direction, for example through an optical conductor, to illuminate the sensor 5 and / or the area around the sensor 5. The light beam is then deflected, for example by means of a light scattering element included in the layer 3, so as to leave the composite structure in the vertical direction.

[0148] The technology used for the light source is not limited. The light source used in the present invention can use a variety of different technologies and may include the following technologies: a light guide made of PMMA or other optically effective polymers, which is coupled to one or more LEDs, optionally including edge lighting devices; polyoptic fibers, such as those made of PMMA or glass, which are woven, knitted or otherwise processed into a fabric to form a flexible, ductile indoor lighting device, which is then coupled to one or more LEDs; a background lighting device with an integral optical structure integrated into a bracket, the background lighting device is produced, for example, by means of molding or laser printing, optionally including a reflector, and can be coupled to one or more LEDs; OLED, i.e., organic LED; electroluminescent elements, such as films or plates.

[0149] The light source may preferably be an LED or an electroluminescent element.

[0150] The LED module may be arranged on the B side of the support layer and coupled to the background lighting device. The LED module and the background lighting device may together form a light source. The background lighting device may be in the form of a textile layer made of PMMA, a light guide plate or a light guide film, a light box or a background lighting device, which may be integrated in the support layer. The light source may be covered on its B side by a light exclusion device to prevent the light source from emitting light on the B side of the support layer.

[0151] A combination of an LED module or other lamp and a background lighting device can be used as the light source, wherein the background lighting device can include a light-conducting plate, a film, a textile or a nonwoven structure made of PMMA, for example. A light exclusion device can be arranged on the B side of the light source, i.e. on the side of the light source facing away from the support layer, in order to prevent light from being emitted in undesired directions.

[0152] The LEDs may be arranged in the sensor layer 3 and connected to the area to be illuminated via a light conductor, which may be a transparent foil and may comprise a POF (Plastic Optical Fiber).

[0153] The LED, for example a Pico-LED, or an electroluminescent element may have a thickness of less than 100 μm. The distance from the light source to the touch sensor area 5 is preferably 0.1 to 5 cm.

[0154] A light scattering foil having a thickness of, for example, 1 to 30 μm may be used to homogenize and direct the light to the touch sensor area 5 .

[0155] The area to be illuminated may comprise more than one light source 5. For example, the touch sensor area 5 may have a circular shape and a plurality of LEDs may be arranged circumferentially around the touch sensor area to attract the user's attention or to simplify its orientation.

[0156] Support layer

[0157] This layer is an optional feature of the composite structure of the present invention and may be referred to simply as "layer 4".

[0158] The layer 4 may be light-transmissive or not, it may be a flexible and / or soft material, or a rigid and / or hard material. In one embodiment, the layer 4 is transparent, flexible and soft.

[0159] It can be made of fabric, textile, spacer fabric or foam. In particular, layer 4 can be made of polyolefin foam, woven spacer fabric, light-transmitting shaped fabric or light-transmitting knitted fabric. The material and the thickness of the material must be selected according to the desired properties of the layer, such as light transmittance.

[0160] Layer 4 can be made of transparent or translucent ABS (acrylonitrile butadiene styrene), PP (polypropylene), PC-ABS (polycarbonate ABS) or other suitable materials by means of injection molding, compression molding, vacuum molding, blow molding or other suitable processes.

[0161] In some embodiments, the support layer is light-transmissive only in its area. In this embodiment, the light-transmissive support layer can provide opaque areas in areas that are not to be illuminated, for example, by providing the support layer with an opaque coating or paint layer. In other examples of this embodiment, a cutout is formed in the support layer at the location where the illuminated area is to be arranged, and the light-transmissive insert is installed in the cutout. For example, a cutout can be provided in the area to be illuminated by means of stamping, milling, laser cutting or water jet cutting, and the cutout is replaced by a separate light-transmissive insert. In this case, the support layer component can also be made of non-transparent material, for example, a fiber mat material. The light-transmissive insert can be implemented, for example, in the form of an element composed of PP, ABS, PC-ABS, PMMA (polymethyl methacrylate) or a mixture thereof, and manufactured by means of injection molding or compression molding. The insert covers the area to be illuminated in the finished composite structure. It can be patterned, with graphics and / or optical elements on its B side and / or A side.

[0162] The material used for the support layer or the insert may have a light transmittance of about 80% to 95% (for ABS and PMMA) and 30% to 40% (for PP) respectively. The material used for the light-transmitting layer 1 may have a light transmittance of 10 to 15%, in particular a light transmittance of about 12%. The combination of these materials may result in a light transmittance of 5% to 10% for the composite structure.

[0163] The layer 4 may be a rigid and / or hard material. Examples of such materials are plastics. Such materials may be used in particular in the case where the layer 4 comprises a light-transmitting insert as described above, or in the case where the light source 5 is comprised in a composite structure.

[0164] The layer 4 can additionally be provided with a coating, wherein the coating can consist of, for example, a paint or a film. It is also possible to dye the support layer itself.

[0165] The composite structure comprising layers 1 and 2 and the touch sensor area 5 or layers 1 to 3 can be rigidly connected to the support layer by means of lamination or bonding, for example using an optionally light-transmissive adhesive, such as a transparent double-sided tape, a transparent spray adhesive or other transparent adhesive coating.

[0166] It is also possible to provide a double-sided adhesive film with different viscosities, which is permanently or removably connected on one side to the composite structure consisting of layers 1 and 2 and touch sensor area 5 or layers 1 to 3 and permanently or removably bonded on the other side to the support layer.

[0167] Soft layer 8

[0168] The composite structure of the present invention may include a soft layer 8 which contributes to the desired softness and feel of the composite structure. The soft layer may be a foam or a textile.

[0169] The density of the foam layer is preferably 0.05 to 0.5 g / cm 3 or 0.1 to 0.3 g / cm 3 The thickness of the foam layer is preferably 30 to 3000 μm or 500 to 2000 μm. The gel content of the foam may be 20 to 80% or 30 to 60%. The foam layer may be made of polyolefin, in particular polypropylene.

[0170] The soft layer is selected from the group consisting of soft layers that are part of or attached to any of layers 1 to 4. The soft layer is preferably arranged between layer 1 and layer 2, between layer 2 and layer 3, or between layer 2 or layer 3 (if layer 3 is present) and layer 4.

[0171] More preferably, the soft layer is part of layer 1 and is arranged underneath the dense layer structure.

[0172] In another preferred embodiment, the soft layer is arranged on the A side of layer 4, i.e. between layer 2 or layer 3 (if layer 3 is present) and layer 4. In case the composite structure has a light source arranged at the B side of the support layer, the soft layer is selected to be able to show suitable light transmittance and other desired properties at least in the area to be illuminated, such as low light scattering and / or visibility or invisibility of structural elements of the foam or textile when illuminated.

[0173] In case the composite structure has a light source arranged above the layer 4, the soft layer may be opaque. In this embodiment comprising a soft layer at the A side of the layer 4, the layer 1 may be made of a dense layer only, i.e. without a foam layer or other soft layer. Furthermore, in this embodiment, the soft layer may have the required softness and / or the required light transmittance only in the area to be illuminated, i.e. the area below the touch sensor area 5. The soft layer may have a lower softness and a lower light transmittance in other areas.

[0174] The composite structure comprising layer 1 , layer 2 , touch sensor region 5 , optional sensor layer 3 and soft layer has a Shore A hardness in the range of 60 to 80, regardless of the position of the soft layer in the composite structure.

[0175] Example

[0176] The present invention will be illustrated by the following examples.

[0177] The composite structure was produced in a two-step process. In the first step, a black opaque mask of plastisol was screen printed onto a light-transmitting TPU foil placed on a flat bed to obtain a modified TPU foil, such as Figure 7 As shown. In a second step, the touch sensor is screen printed onto the mask on the modified TPU foil. The touch sensor is a commercially available membrane touch switch made of silver (DuPont 5025). Curing is carried out at 100°C for 10 minutes. Electrodes and ground connections are mounted to the composite structure.

[0178] The composite structure obtained by this process is shown in an exploded view of the composite structure. Figure 5 Shown in.

[0179] Fig. 8A and Figure 8B The advantageous effects of the composite structure are shown, in particular the matte hiding properties of the composite structure.

[0180] Reference numerals list

[0181] 1 light-transmitting layer

[0182] 2 Opaque layer including light-transmitting area.

[0183] 3 Sensor Layer

[0184] 5 touch sensor areas

[0185] 6Transparent area within the opaque layer 2

[0186] 7Dense layer

[0187] 8 soft layers

[0188] 9 coats of paint

[0189] 11 touch sensor area 5 touch sensors

[0190] 12 light-transmitting area of ​​touch sensor area 5

Claims

1. A composite structure, wherein: The composite structure comprises, in sequence, a light-transmitting layer (1), an opaque layer (2), and a sensor layer (3), wherein the sensor layer (3) comprises a touch sensor area (5) and at least comprises an electrical conductor connected to the touch sensor area (5), - the light transmittance of the light-transmitting layer (1) is 1 to 50%, - the opaque layer (2) is arranged below the light-transmitting layer (1), has a thickness of 1 to 100 μm, and comprises a first light-transmitting region (6), which is a void region surrounded by the opaque region of the opaque layer (2), - the sensor layer (3) is applied by printing, The touch sensor area (5) has a thickness of 0.5 to 30 μm, is in direct contact with the light-transmitting layer (1) in the first light-transmitting area (6) of the opaque layer (2), and comprises: - a touch sensor (11) arranged completely below the opaque area of ​​the opaque layer (2), and A second light-transmitting area (12) is arranged at least partially below the first light-transmitting area (6) of the opaque layer (2).

2. The composite structure according to claim 1, wherein: The opaque layer (2) is a masking layer.

3. The composite structure according to claim 1 or 2, wherein the composite structure comprises a light-transmitting layer (1), an opaque layer (2), a touch sensor area (5) and a support layer in sequence, wherein: The support layer is light-transmissive or at least partially light-transmissive.

4. The composite structure according to claim 1 or 2, comprising a light source arranged in or attached to at least one of the following layers: an opaque layer (2), a sensor layer (3) and a support layer.

5. A composite structure according to claim 1 or 2, comprising a soft layer, which is included in the light-transmitting layer (1) below one or more dense layers (7) or is arranged between a support layer and a light-transmitting sensor layer (3).

6. The composite structure according to claim 1 or 2, wherein: The light-transmitting layer (1) is the visible side of the composite structure and is selected to make other elements of the composite structure invisible in the absence of light emitted from a light source arranged in the composite structure or at the back side of the composite structure.

7. The composite structure according to claim 6, wherein: The light-transmissive element is selected to allow transmission of visible light emitted from a light source disposed in or at the back side of the composite structure, while the opaque region is selected to inhibit transmission of visible light emitted from a light source disposed in or at the back side of the composite structure.

8. A method for producing a composite structure according to any one of claims 1 to 7, the method comprising: Step (i), applying an opaque layer (2) including a first light-transmitting region (6) on the light-transmitting layer (1); And then step (ii) of applying a sensor layer (3) including a touch sensor area (5) on the light-transmitting layer (1).

9. The method according to claim 8, wherein: The layers are applied by printing in steps (i) and (ii), the opaque layer (2) comprising the first light-transmitting area (6) being the masking layer.

10. The method according to claim 8 or 9, wherein: Both steps (i) and (ii) are printing steps selected from screen printing and inkjet printing.

11. The method according to claim 8 or 9, wherein: Step (i) is to print an opaque mask layer, and step (ii) is to print a sensor layer (3).

12. The method according to claim 8, comprising: Step (a), applying an opaque layer (2) including a light-transmitting area on the sensor layer (3); and step (b), applying the modified sensor layer (3) obtained in step (a) on the light-transmitting layer (1).

Images