GB2598368A

GB2598368A - An illuminated car interior panel

Info

Publication number: GB2598368A
Application number: GB2013545.5A
Authority: GB
Inventors: Cracana Roxana; Overton-Smith James; Warren Kevin
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2022-03-02
Anticipated expiration: 2040-08-28
Also published as: GB202013545D0; GB2598368B

Abstract

The invention provides an interior car panel (2) comprising: a carrier (6) for securing to a car interior; an illuminating element (10, 12, 14) mounted on the carrier; a profile-defining layer (8) secured to the carrier (6) so that it conceals the illuminating element (10, 12, 14), the profile-defining layer (8) being formed from an at least partially transparent material; a light-impermeable layer (24) which covers the profile-defining layer (8), the light impermeable layer (24) having a window (26) therein through which light from the illuminating element (10, 12, 14) may pass; and one or more layers of lacquer (28, 30, 32) coating the light-impermeable layer (24) and obscuring the window (26); wherein at least one (28) of the layers of lacquer (28, 30, 32) is tinted and wherein the layers of lacquer (28, 30, 32) together form a light barrier which renders the window (26) in the light-impermeable layer (24) substantially invisible when the illuminating element (10, 12, 14) is switched off but allows images formed in or by the window (26) to be seen when the illuminating element (10, 12, 14) is switched on.

Description

AN ILLUMINATED CAR INTERIOR PANEL

Introduction

The present invention relates to a means of creating a static or moving image on an interior car panel such as a fascia panel wherein the image remains hidden until it is illuminated

Background to the Invention

Various proposals have been made for backlit decorative surfaces for use in motor vehicles.

WO 2019/214957A1 (Eissmann Automotiv Deutschland GMBH) discloses a method of providing a backlit decorative surface for the interior of a motor vehicle wherein a light transmissive film is laminated onto the back of a decorative layer covering a light source. A laser is then used to cut perforations through the thickness of the decorative layer, but without penetrating the underlying film.

WO 02/061380 (Textron Automotive Company) and US 2002/0101738 (Misaras) each disclose a method and apparatus for backlighting an automotive trim panel, such as an instrument panel, by perforating a cover layer with a laser so that light from a low-heat light source such as an LED can "bleed through the perforations so as to be seen by the vehicle occupant". The cover layer typically overlies a cushion or foam layer which does not appear to be transparent. An optional transparent or translucent layer can be applied over the perforations in the cover layer to prevent them from becoming clogged with dust.

The optional layer can be tinted and can be a coating layer such as a paint.

US 2019/0283667 (Eissmann Automotiv Deutschland GMBH) discloses a method of providing a backlit decorative surface for the interior of a motor vehicle similar to that disclosed in WO 2019/214957A1 except that the perforations extend through both the decorative layer and the underlying film.

US 10,442,348 (Novem Car Interior Design GmbH) discloses an illuminated interior car panel which comprises a carrier and a decorative layer. The carrier can be formed from a light-permeable plastics material and decorative layer formed from a light impermeable material such as aluminium. The decorative layer has laser-cut oblique light passages through its thickness so that images created by light passing through the passages from a light source behind the carrier can only be seen by selected occupants of the car. The light passages preferably have a small cross section so that the passages cannot be seen when the light source is switched off. A protective coating is provided on the front surface of the decorative layer but the nature of the protective coating is not specified.

DE10 2011 082 344 (Lisa Draxlmaier GmbH) discloses a perforated, backlit decorative layer for vehicle interiors. Leather is a preferred material for the decorative layer. The decorative layer may be provided with a protective light-transmitting lacquer coating.

DE102008054721 (Lisa Draxlmaier GmbH) discloses a perforated, backlit decorative layer for vehicle interiors where the decorative layer (preferably formed from natural or synthetic leather) is provided with one or more protective transparent but light scattering cover layers.

The Invention The present invention provides a means of creating a static or moving image on an interior car panel such as a fascia panel wherein the image remains hidden until it is illuminated Accordingly, in a first aspect, the invention provides an interior car panel comprising: a carrier for securing to a car interior; an illuminating element mounted on the carrier; a profile-defining layer secured to the carrier so that it conceals the illuminating element, the profile-defining layer being formed from an at least partially transparent material; a light-impermeable layer which covers the profile-defining layer, the light-impermeable layer having a window therein through which light from the illuminating element may pass; and one or more layers of lacquer coating the light-impermeable layer and obscuring the window; wherein at least one of the layers of lacquer is tinted and wherein the layers of lacquer together form a light barrier which renders the window in the light-impermeable layer substantially invisible when the illuminating element is switched off but allows images formed in or by the window to be seen when the illuminating element is switched on.

The light-impermeable layer may have a single window or more than one window. The window(s) can take the form of a stencil or outline of a shape so that a shaped image is formed by the window when the illuminating element is switched on and the window is illuminated. For example, the window(s) can be shaped to form a logo or name.

Alternatively, the window may be of a more regular shape, for example rectangular or elliptical so that images of varying shapes and forms, both static and dynamic, can be viewed in the window(s).

The layers of lacquer together form a light barrier which renders the window in the light-impermeable layer substantially invisible when the illuminating element is switched off but allows the window to be seen when the illuminating element is switched on. The term "substantially invisible" means that under the ambient lighting conditions usually found in the automobile, the window (e.g. the outline of a logo or a name) cannot be seen, or at least cannot be seen from a distance of more than about 10 cm. It will be appreciated that under some lighting conditions, for example if a strong light source is directed on to the panel, it may be possible to see a faint outline of the shape of the window before the illuminating element is switched on.

The profile-defining layer is a generally rigid layer that defines the shape of the panel. The term "layer" is not intended to imply any limitations as to its thickness and the way in which it is constructed and it will typically vary in thickness along its length and width. The profile-defining layer may, for example, be a moulded element which is secured to the carrier so as to cover the illuminating element. It can be moulded separately and then secured to the carrier, for example by mechanical means or by adhesive or a combination thereof. Alternatively, it can be moulded in situ on the carrier. The profile-defining layer is formed from a material which is at least partially transparent to light. Typically it has a transparency to light of greater than 60%, more usually greater than 70% and most usually greater than 85%.

The profile-defining layer is typically formed from a tough durable mouldable or thermoformable plastics material. One such material is a polycarbonate.

The profile-defining layer is covered by a light-impermeable layer in which are present one or more windows through which light from the illuminating element may pass. The light-impermeable layer makes little or no contribution to the structural strength of the panel and is typically no more than about 0.5 mm thick. Thus, for example, it can have a thickness in the range from 0.05 mm to 0.3 mm.

The light-impermeable layer can be constituted by one or more layers of paint having a layer thickness and pigment content sufficiently high to render it opaque. The light-impermeable layer can vary in colour provided that it is opaque but, in one embodiment, is black in colour.

The window(s) in the light-impermeable layer can be created in a number of different ways but typically they are created by laser etching. The laser etching can be achieved by using a CO2 laser type and a 10600 nm wavelength.

The light-impermeable layer is coated by one or more layers of lacquer which, in addition to providing further mechanical protection for the underlying light-impermeable layer, fill in and obscure the window(s). At least one of the layers of lacquer is tinted. The layer(s) of lacquer together form a light barrier which renders the window in the light-impermeable layer substantially invisible when the illuminating element is switched off but allows images formed in or by the window to be seen when the illuminating element is switched on. The thicknesses of the layer(s) of lacquer and the concentrations of pigment in the lacquer necessary to obscure the window while still allowing acceptable light transmission when the illuminating element is switched on can readily be determined by trial and error.

In one embodiment, the light-impermeable layer is coated by two or more layers of lacquer.

The layers of lacquer preferably ensure that the interior car panel has a front surface (cabin-facing surface) which is smooth and generally free from perforations and visible blemishes. The surface may have a high gloss finish.

The carrier is a body on which the illuminating element and the profile-defining layer are mounted. The carrier is provided with one or more formations (e.g. tabs, brackets, prongs, threaded holes, clips, spigots or plug-like elements) that enable the carrier to be firmly secured to an interior structural element of the automobile. The carrier can be formed from a variety of materials, including wood, plastics materials or metal and can be a unitary or composite element. In one embodiment, the carrier is formed from cast aluminium.

The illuminating element is an element which acts as a source of light or an image or images that can be seen through the window in the light-impermeable layer. The illuminating element is typically a flat element, i.e. it has a depth which is considerably less than its length and width. Depending on the nature of the illuminating element, it can be substantially planar or non-planar. In one embodiment, it is substantially planar.

The illuminating element can comprise or can be, for example, an LED-driven light guide, an LCD (liquid crystal display) screen or an OLED (organic light-emitting diode) screen.

In one embodiment, the illuminating element is an LED-driven light guide. The LED-driven light guide typically comprises a strip or sheet of a light guide material (a light guide strip or LGS), a reflective backing layer or sheet for the LGS, and an array of LEDs at one or more edges of the LGS for directing light into and along the LGS guide.

The array(s) of LEDs typically take the form of strips that are positioned in a coplanar orientation with the LGS guide, in order to facilitate travel of the emitted light through and along the LGS.

The light guide material is an optically transparent material such as a transparent plastics material. Light from the LEDs is transmitted into and along the LGS. It is important that the light being transmitted through the length of (i.e. along) the LGS is visible through the window(s) in the light-impermeable layer. Therefore the LGS typically has light scattering properties, such that a large proportion of the light passing along the LGS is redirected out through a front (i.e. cabin-facing) surface of the LGS, i.e. in a direction generally orthogonal to a plane of the LGS. Light which is redirected out of the rear surface of the LGS is reflected back into the LGS by the reflective backing layer or sheet.

The light scattering properties of the LGS can be provided in a variety of ways, for example by V-cutting, dot printing, laser dot etching and particulate inclusion.

In v-cutting, a v-shaped blade creates a grid on the bottom of the LGS by etching a series vertical and horizontal lines. The depth and spacing of these lines is carried out meticulously so as to optimize the evenness and the brightness of light released. The vertical v-grooves are widely spaced when they are close to the light source, but narrowly spaced when they are further away from the light source. The horizontal v-grooves gradually grow wider and deeper as their distance from the light source increases. Therefore, the brightness of the front (cabin-facing) surface of the LGS is able to remain uniform.

In dot printing, a matrix of fine dots is printed onto the LGS using diffusive ink. These dots help scatter the light emitted from the LEDs. However, a downside to dot printing is that the ink is less effective at refracting light and therefore the illuminating element is not as bright as it can be when other light scattering constructions are used.

Adding particulates to the LGS resin itself is another option. These particulates are scattered throughout the LGS and reflect light in all directions when combined with a light source. Using diffusion particles is an extremely efficient way to produce an LGS.

Although, similar to dot printing, the particulates aren't able to reflect as much light out of the front of the panel as with v-cutting.

A currently preferred means of imparting the light scattering properties to the LGS is by means of laser etching an array of dots on the surface of the LGS using a CO2 laser type and a 10600 nm wavelength, the laser etching programme being tuned according to the particular surface geometry of the LGS. The spacings between the dots are such that the brightness of the front (cabin-facing) surface of the LGS remains uniform. For example, when the illuminating element comprises an LGS having an array of LEDs along one edge, the laser-etched dots are typically arranged in rows such that the rows are more widely spaced apart when they are close to the LED array, but more narrowly spaced apart when they are further away from the LED array. When the illuminating element comprises an LGS and a pair of arrays of LEDs on opposing edges of the LGS, the laser-etched dots are typically arranged in interspersed rows such that the light transmission provides a substantially constant brightness across the surface and a substantially homogeneous light transmission through the painted/lacquered layers.

In one embodiment of the invention, the illuminating element is an LED-driven light guide which comprises an LGS in the form of a substantially rectangular strip or sheet of a light guide material, a reflective backing layer or sheet for the LGS, and a pair of linear LED arrays, the two linear LED arrays being located on opposing edges of the LGS, wherein the light guide material bears an array of light-scattering laser-etched dots spaced apart in such a way as to provide a substantially uniform brightness across the LGS.

The LEDs may be programmable. For example, the LEDs can be programmable RGB (red-green-blue) LEDs, e.g. ISELEDs.

In one embodiment, ISELEDs are embedded in the LGS. An ISELED is a digital RGB LED capable of being statically and dynamically controlled. RGB LEDs combine three colours (red, green and blue) to produce over 16 million hues of light. As such, each ISELED may be programmed individually to behave in a certain way that is independent from the other ISELEDs in the same network.

A dispersion of ISELEDs in the LGS has a number of advantages. In particular, because each ISELED is individually controllable, the panel illumination may be highly dynamic.

Suitable materials for the LGS include polycarbonate (PC), acrylate polymers or copolymers such as polymethyl methacrylate (PMMA), thermoplastic polyurethane (TPU) and polyesters such as polyethylene terephthalate (PET).

A particular acrylate for use as an LGS material is polymethylmethacrylate (PMMA).

The LGS typically has a thickness in the range from 0.5 mm to 5 mm, more usually from 1 10 mm to 3 mm, for example from 1.5 mm to 2.5 mm.

The interior car panels of the invention are integral parts of the automobile and are not ordinarily intended to be removable, except for the purposes of inspection, servicing and repair by a skilled technician. As such, they are fitted during the assembly of the automobile. It follows that, in a further aspect, the invention provides an automobile integrally provided with one or more interior car panels are defined herein.

The invention also provides a method of making an interior car panel as hereinbefore defined, the method comprising: (a) creating a sub-assembly comprising the carrier, illuminating element, profile-defining layer, and the light-impermeable layer; (b) laser etching one or more light transmitting windows through the light-impermeable layer; and (c) applying one or more layers of lacquer to the light-impermeable layer so as to cover the light-impermeable layer and fill the window; wherein at least one of the layers of lacquer is tinted and wherein the layers of lacquer together form a light barrier which renders the window in the light-impermeable layer substantially invisible when the illuminating element is switched off but allows images formed in or by the window to be seen when the illuminating element is switched on.

In step (a), the sub-assembly comprising the carrier, illuminating element and profile-defining layer can be formed by securing the illuminating element to the carrier and then either: (a-i) securing a pre-formed profile-defining layer to the carrier so that the illuminating element is sandwiched between the carrier and the profile-defining element; or (a-u) forming the profile-defining element in situ on the carrier (e.g. by moulding) so that the illuminating element is sandwiched between the carrier and the profile-defining element.

When the profile-defining layer is preformed and then secured to the carrier, it can be covered with the light-impermeable layer either before or after it is secured to the carrier.

The profile-defining layer is typically covered by the light-impermeable layer using a coating process such as painting. Typically, the coating (e.g. paint) is applied by dipping or spraying, usually in a number of coats with sanding between coats to provide the desired smooth finish.

Brief Description of the Drawings

Figure 1 is a front view (cabin-facing view) of an interior car panel (fascia panel) according to one embodiment of the invention.

Figure 2 is a photograph of the fascia panel of Figure 1 in an unactivated state with the illuminating element switched off.

Figure 3 is a photograph of the fascia panel of Figure 1 in an activated state with the illuminating element switched on.

Figure 4 is a sectional elevation along line B-B in Figure 1.

Figure 5 is a rear view of the fascia panel of Figures 1 to 3, but prior to application of the lacquer layers.

Figure 6 is an enlarged view of the region marked "C" in Figure 5.

Figure 7 is a schematic exploded view showing the various layers making up the fascia panel of Figures 1 to 3.

Figure 8 is a schematic cross sectional view showing the arrangement of the light-impermeable layer and the lacquer layers present in the fascia panel of Figures 1 to 3.

Detailed Description of the Invention

The invention will now be illustrated, but not limited, by reference to the embodiments shown in the accompanying drawings Figures 1 to 8.

Figures 1, 2 and 3 are front views of a fascia panel (2) according to one embodiment of the invention. In this embodiment, the fascia panel (2) is the right hand (passenger facing) fascia panel for a left hand drive automobile.

The fascia panel (2) has no discernible surface features apart from an opening (4) in which is mounted an air inlet nozzle. The fascia panel has a dark high gloss appearance and, in the unactivated state shown in Figure 2, displays no logos, words, patterns or other features on its surface. Figure 3 shows the fascia panel (2) when an illuminating element inside the panel has been activated. In the activated state, images of the word "GHOST" and a constellation of star-like dots become visible. When the illuminating element inside the fascia panel (2) is deactivated, the images disappear.

The structure of the fascia panel (2) can be seen from Figures 4 and 7. Thus, the fascia panel (2) comprises a carrier (6) to which is secured a profile-defining layer (8). Sandwiched between carrier (6) and the profile-defining layer (8) is an illuminating element in the form of an LED driven light guide (10, 12, 14).

The carrier (6) in this embodiment is formed from cast aluminium and its structure is shown in more detail in Figure 5 which is a view from the rear side of the carrier. As can be seen from Figures 4 and 5, the carrier has a number of prongs (16 &18), brackets (20 & 22), and various other formations (not labelled), including threaded formations, that enable it to be secured to an underlying support structure of the automobile.

The LED driven light guide comprises a light guide strip (LGS) (10) which is approximately rectangular in shape and is formed from polymethylmethacrylate sheet which, in this embodiment, is 2 mm thick. The LGS (10) has an array of laser etched dots across substantially all of its area. In this particular embodiment, there are about 90,000 laser etched dots, each having a diameter of 0.3 mm, although it will be appreciated that fewer or more dots may be present and different diameters may be used. The dots provide a means for scattering light passing along the LGS (10) so that a substantial proportion of -10 -the light is directed out through the front surface of the LGS. The LGS is illuminated by a pair of LED strips (12) located at opposing edges (the top and bottom edges) of the LGS (10). Only one of the LED strips (12) is shown in the Figures. In this particular embodiment, each LED strip has 76 LEDs but it will be appreciated that fewer or more LEDs may be used as desired. Where it is desired only to create fairly simple illuminated images on the fascia panel, white LEDs may be used. Alternatively, for more dynamic displays, coloured ISELEDS may be used, in which case an electronic controller will be required to control the dynamic behaviour of the LEDs.

In order to increase the amount of light directed in a forwards direction (i.e. towards the automobile cabin interior), a reflective foil layer (14) is located behind the LGS. The reflective foil layer can be a layer of a white pigmented polymer such as polyethylene terephthalate (PET) or it can be a layer of polymer bearing a thin metal coating.

The profile-defining layer (8) is formed from an optically transparent grade of moulded polycarbonate. The rear surface of the profile-defining layer (8) is generally flat in order to fit against the flat LGS. The front surface of the profile-defining layer (8) is contoured to provide a desired profile for the fascia panel. By way of example, the profile-defining layer (8) can vary in thickness over its area from about 3 mm to about 10 mm in order to provide the desired profile.

The forward surface of the profile-defining layer (8) is coated with a layer (24) of a dark (e.g. black) pigmented paint, the thickness and pigment density of which are such as to provide a light-impermeable layer. The light-impermeable layer (24) is provided with a window (26) through which light from the LED driven light guide can pass. The window is formed by laser etching the light-impermeable layer (24) and can take a variety of different shapes and sizes depending on the nature of the images to be created on the fascia panel. For example, in one embodiment, the window (26) can take the form of a simple laser etched stencil of a word or shape or logo. Such an embodiment would typically be used in conjunction with a static LED display, although dynamic variations in the colours of the word, shape or logo could be achieved using a dynamic LED display.

In another embodiment, the window (26) has a more regular shape, for example a rectangular or elliptical (e.g. circular or oval) shape and is intended to function as a screen though which a dynamic LED display can be viewed.

As can be seen from Figure 2, when the illuminating element is unactivated, no image can be seen on the fascia panel, not even an outline of the window (except perhaps when viewed very close up from only a few centimetres). The invisibility of the window (26) is achieved by coating the light-impermeable layer (24), and filling the window (26), with one or more (e.g. three) coats (28) of tinted lacquer. The lacquer can be, for example a polyester lacquer. The thickness and number of tinted lacquer coatings applied and the pigment density in the lacquer are chosen such that the window is substantially invisible when the illuminating element is unacfivated but can be seen when the illuminating element is activated. The layer of tinted lacquer is coated in turn by a protective coating (30) of clear polyester lacquer and then a top coat(s) of a polyurethane lacquer (32). The total thickness (not including the depth of the window) of the combined tinted lacquer layer (28), clear polyester layer (30) and polyurethane top coat (32) is in the range 0.3 mm to 0.5 mm.

The fascia panel can be connected to the automobile's electronic control systems and programmed so that the illuminating element is switched on automatically, and the images displayed on the panel when the driver of the automobile opens a door or when the engine is started up. Alternatively, the illuminating element may be switched on in a separate operation and hence a decision on whether or not to display images on the fascia panel can be controlled by an occupant of the automobile. The electronic control system to which the illuminating element is connected may also be programmed to allow the selection of a number of different displays.

The invention has been illustrated by reference to a fascia panel but it will be appreciated that the invention can in principle be used in various other locations in the interior of an automobile. For example, the interior car panel of the invention could be an interior side panel or door panel, or a pivotable panel such as a pivoting table panel (picnic table") secured to the rear of a seat or to another barrier separating front and rear seats in the automobile.

The invention has also been illustrated by reference to a panel in which the illuminating element is an LED driven light guide. As alternatives, an LCD (liquid crystal display) screen or an OLED (organic light-emitting diode) screen can be used instead of the LED driven light guide.

Equivalents -12 -The embodiments illustrated in the Figures and specifically described above are presented for the purpose of illustrating the invention and should not be construed as imposing any limitation on the scope of the invention. It will readily be apparent that numerous modifications and alterations may be made to the specific embodiments of the invention described above and illustrated in the Figures without departing from the scope of the claims appended hereto. All such modifications and alterations are intended to be embraced by this application.

Claims

-13 -CLAIMSAn interior car panel comprising: a carrier for securing to a car interior; an illuminating element mounted on the carrier; a profile-defining layer secured to the carrier so that it conceals the illuminating element, the profile-defining layer being formed from an at least partially transparent material; a light-impermeable layer which covers the profile-defining layer, the light-impermeable layer having a window therein through which light from the illuminating element may pass; and one or more layers of lacquer coating the light-impermeable layer and obscuring the window; wherein at least one of the layers of lacquer is tinted and wherein the layers of lacquer together form a light barrier which renders the window in the light-impermeable layer substantially invisible when the illuminating element is switched off but allows images formed in or by the window to be seen when the illuminating element is switched on.
2. An interior car panel according to claim 1 wherein the profile-defining layer is formed from a material which has a transparency to light of greater than 70% and most usually greater than 85%.
3. An interior car panel according to claim 2 wherein the profile-defining layer is formed from a polycarbonate.
4. An interior car panel according to any one of claims 1 to 3 wherein the light-impermeable layer has a thickness in the range from 0.05 mm to 0.3 mm.
5. An interior car panel according to any one of claims 1 to 4 wherein the light-impermeable layer is constituted by one or more layers of paint having a layer thickness and pigment content sufficiently high to render it opaque.
6. An interior car panel according to any one of claims 1 to 5 wherein the illuminating element is an LED-driven light guide, an LCD (liquid crystal display) screen or an OLED (organic light-emitting diode) screen.
7. An interior car panel according to claim 6 wherein the illuminating element is an LED-driven light guide which comprises a light guide strip (LGS) in the form of a substantially rectangular strip or sheet of a light guide material, a reflective backing layer or sheet for the LGS, and a pair of linear LED arrays, the two linear LED arrays being located on opposing edges of the LGS, wherein the light guide material bears an array of light-scattering laser-etched dots spaced apart in such a way as to provide a substantially uniform brightness across the LGS.
8. An interior car panel according to claim 6 wherein the illuminating element is a liquid crystal display.
9. An interior car panel according to any one of claims 1 to 8 wherein the carrier is formed predominantly from a metal such as aluminium.
10. An interior car panel according to any one of claims 1 to 9 which is a fascia panel.
11. An automobile fitted with one or more interior car panels are defined in any one of claims 1 to 10.
12. A method of making an interior car panel as defined in any one of claims 1 to 10, the method comprising: (a) creating a sub-assembly comprising the carrier, illuminating element, profile-defining layer, and the light-impermeable layer; (b) laser etching one or more light transmitting windows through the light-impermeable layer; and (c) applying one or more layers of lacquer to the light-impermeable layer so as to cover the light-impermeable layer and fill the window; wherein at least one of the layers of lacquer is tinted and wherein the layers of lacquer together form a light barrier which renders the window in the light-impermeable layer substantially invisible when the illuminating element is switched off but allows images formed in or by the window to be seen when the illuminating element is switched on.