DE102016211074A1 - Luminous element for use in a vehicle interior - Google Patents

Abstract

The application relates to a lighting element (1) for use in a vehicle interior (2). The proposed luminous element (1) comprises a semitransparent layer (3) having a front side (4) and a rear side (7) and a light source (15) arranged behind the semitransparent layer (3). The front side (4) of the semitransparent layer (3) is flat and the rear side (7) of the semitransparent layer (3) has at least one depression (2), so that the semi-transparent layer (3) has at least one first region (10) a first thickness (d1) and at least one second region (11) having a second thickness (d2). The first thickness (d1) is less than the second thickness (d2). The first region (10) is arranged to transmit light emitted by the light source (15). The second region (11) is arranged to absorb light emitted from the light source (15) and thereby to transmit less light than the first region (10).

Description

The application relates to a luminous element for use in a vehicle interior according to the preamble of claim 1.

From the prior art, lighting elements for use in vehicle interiors with so-called black-panel surfaces known. The purpose of such lighting elements is to produce a particularly high-quality appearance, for example, by the symbols to be displayed by the lighting elements for a viewer from the vehicle interior are not visible when the lighting elements are turned off. A black panel effect can be generated, for example, by a lighting element having a smoked glass pane on a side facing the vehicle interior. The smoked glass pane is usually backlit by a light source arranged on a side of the luminous element facing away from the vehicle interior. In order to generate luminous symbols, areas of the smoked glass pane are masked on the side facing away from the vehicle interior with an aperture material. If the ambient brightness is sufficiently weak, the masked areas are visually imperceptible when the light source is switched off from the vehicle interior, and the lighting element gives a high-quality, optically homogeneous impression.

The object of the present application is to propose a luminous element for use in a vehicle interior, which, in particular when the light source is switched off, conveys a visually high-quality impression and is relatively inexpensive, quick and easy to produce.

This object is achieved by a luminous element having the features of the main claim. Advantageous developments emerge with the features of the dependent claims and the embodiments.

The proposed luminous element is suitable for use in a vehicle interior. The luminous element comprises a semitransparent layer having a front side and a rear side and a light source arranged behind the semitransparent layer. The front side of the semitransparent layer is flat and the back side of the semi-transparent layer has at least one depression, such that the semitransparent layer has at least one first region with a first thickness and at least one second region with a second thickness. The first thickness is less than the second thickness. The first region is configured to transmit light emitted by the light source. The second region is arranged to absorb light emitted from the light source and thereby to transmit less light than the first region.

The semitransparent layer is arranged to absorb light emitted by the light source and light penetrating from the vehicle interior into the semitransparent layer. The light source is, for example, a light emitting diode. The light source may also be a light guide in which light from a more distant, active radiation source, such as a light emitting diode, can be derived. When the light source is switched off, the first region and the second region can not be distinguished from one another in the case of usually occurring ambient brightnesses, because the light passing from the vehicle interior through the semitransparent layer and reflected back into the vehicle interior by areas behind it does not show either in the first or in the interior the second region has a perceptible intensity. In addition, the luminous element acts optically homogeneous in that the front side of the semitransparent layer is flat.

When the light source is switched on, the light emitted thereby passes through the semitransparent layer into the vehicle interior. Due to the different thicknesses, the light emitted by the light source is absorbed to different degrees as it passes through the first and second regions of the semi-transparent layer. Here, a transmitted light intensity with increasing thickness typically decays exponentially.

In particularly preferred embodiments, the second region has a sufficiently large thickness, so that, even when the light source is switched on, it can not be perceived as a luminous surface when viewed from the vehicle interior. The first region, on the other hand, is sufficiently thin that it can be perceived as a luminous surface. The extent of the first region in a plane of the semitransparent layer usually corresponds to the shape of a symbol or character to be displayed.

The proposed luminous element has a comparatively simple construction, for which only a few different components have to be used. As a result, a fast and cost-effective production process can be devised.

Typically, the semi-transparent layer is integrally formed, whereby the impression of optical homogeneity with the light source switched off can be further enhanced. In addition, the number of components used remains low. In addition, in typical implementations in the first region and in the second region, the semitransparent layer has the same Absorption coefficient on. The absorption coefficient of the semitransparent layer may be at least 0.1 mm ^-1 , for example at least 0.4 mm ^-1 , and / or at most 5 mm ^-1 , for example at most 2 mm ^-1 . For example, the semitransparent layer in the first region and in the second region may be substantially homogeneous with respect to their intense optical properties.

It can be provided that a transmittance in the first region corresponds to at least a tenfold, preferably at least a hundredfold, transmittance in the second region. In this way, a sufficient brightness difference between the first region and the second region can be achieved when the light source is switched on. The transmittance is to be understood as the ratio of transmitted to incident light intensity with normal incidence of green light with a wavelength of 550 nm.

The second thickness may be greater than the first thickness by at least 200 μm, preferably at least 500 μm. For example, the first thickness may be at least 50 μm. The second thickness may be, for example, at most 5 mm.

In typical embodiments, the semitransparent layer contains a plastic. It can be provided, for example, that the semitransparent layer contains polymethyl methacrylate and / or polycarbonate. The semi-transparent layer may be a tinted layer. The semitransparent layer may for example be an injection molded part. In this case, the layer is characterized by a low weight and a simple production.

In addition, a translucent support may be provided which is arranged between the semitransparent layer and the light source. The carrier may be connected to the semitransparent layer and / or to the light source. The carrier can give the luminous element a sufficient stability, which is particularly advantageous if the semi-transparent layer is not sufficiently stable due to a small thickness or for other reasons. An absorption coefficient of the support is less than the absorption coefficient of the semitransparent layer in preferred embodiments. The transmittance of the carrier in a region overlapping with the first region of the semitransparent layer is typically greater than the transmittance of the semitransparent layer in the first and / or second region.

The carrier may, for example, be arranged behind the first region and / or behind the second region. The carrier may for example be formed in one piece. Typically, the carrier comprises a plastic, for example polymethylmethacrylate, polypropylene and / or polycarbonate. A back side of the carrier facing the light source can be flat. Alternatively, the carrier may have reinforcing ribs on the back side. The reinforcing ribs can also be designed, for example, for fastening the light source to the carrier. The carrier is typically at least 1 mm and / or at most 3 mm thick in the area behind the first and / or second region.

The carrier may fill the at least one recess. In some embodiments, the light emitted by the light source may pass through the carrier largely unaffected. However, it can also be provided that the carrier is set up to transmit and / or scatter the light emitted by the light source. For this purpose, the carrier may, for example, have optically active inhomogeneities which act as optical scattering centers. For example, the carrier may for this purpose include inclusions of a material different from the material of the remaining carrier or of air. The carrier may, for example, comprise and / or be made of a light-diffusing material such as milky polypropylene.

In this way, it can be achieved that the light emitted by the light source receives a broad distribution of directional vectors and is radiated into the vehicle interior at a large solid angle. Thus, the luminous first region is visible from many different viewing directions from the vehicle interior.

In some embodiments, a light-permeable protective layer is provided, which covers the front of the semi-transparent layer at least partially. Typically, the protective layer forms the foremost layer on a visible side of the luminous element. The protective layer may be, for example, a lacquer layer. The protective layer can be designed to prevent scratching or other damage to the semitransparent layer and thus to bring about increased longevity of the luminous element.

The protective layer can also develop a visual aesthetic effect. For example, the protective layer may be semitransparent. The protective layer may comprise, for example, wood and / or stone.

The recess may have a substantially rectangular cross-section, so that side walls of the recess are oriented substantially parallel to each other. In this way, sharply contoured luminous symbols, in which the first and second regions are sharply separated, can be generated. Typicherweise run the Regions of the backside of the semitransparent layer in the first region parallel to the regions of the backside of the semitransparent layer in the second region.

According to one embodiment, the back side of the semitransparent layer in the first region is roughened at least in regions. A mean square roughness (rms roughness) in this case is for example at least 1 μm, preferably at least 2 μm and / or, for example, at most 40 μm, preferably at most 20 μm. By roughening the back of the semitransparent layer in the first region, a divergence of the light emitted by the light source can be achieved. This results in a broadening of the solid angle, in which the light is emitted.

Additionally or alternatively, broadening of this solid angle can be achieved by having the semitransparent layer in the first region having light-scattering pigments. The light-scattering pigments may contain, for example, TiO ₂ . Moreover, it can be provided that the protective layer has light-scattering pigments in a region overlapping with the first region, likewise, for example, TiO ₂ .

In addition, side walls of the recess may be at least partially reflective. For this purpose, the side walls may for example have a reflective coating. It can also be provided that, given the carrier that fills the depression, refractive indices of the carrier and of the semitransparent layer are selected such that the light emitted by the light source is reflected on the side wall. It can also be provided that the side walls are particularly smooth and consequently reflective. For example, the sidewalls may have an average roughness rms (rms roughness) of at most 1 μm, in particular at most 50 nm. Typically, a roughness of the sidewalls is less than a roughness of the backside of the semitransparent layer in the first region.

Thereby, the intensity of the light in the first region can be increased and thus a power consumption of the light source can be reduced. In addition, this can prevent the light emitted by the light source from penetrating laterally into the second region of the semitransparent layer and, if appropriate, emerging from the semitransparent layer again via a surface of the second region facing the vehicle interior. Thus, it can be achieved by the reflective side walls that contours of an illuminated first region of the semitransparent layer appear sharper.

The first and / or the second region may simply be contiguous or not simply contiguous. Typically, the first region has at least one area with a vehicle interior facing surface of at least 2 mm ² . In this way, at least this region of the first region of the vehicle interior is visually perceptible when the light source is turned on.

For the purposes of the present application, it is to be understood that the corresponding surface has no steps with a height of more than 100 μm, preferably more than 50 μm. But it can certainly be provided that the corresponding surface is curved.

An embodiment will be described below with reference to the drawings. Show it

1 a cross section through a luminous element,

2 a plan view of the lighting element with the light source and

3 a plan view of the lighting element with the light source switched off.

In 1 is a schematic cross section through a luminous element 1 for use in a vehicle interior 2 shown. The light element 1 comprises a semi-transparent layer 3 made of a plastic, for example an injection-molded part made of PMMA or PC. The semitransparent layer 3 includes a completely smooth and stepless front 4 that the vehicle interior 2 is facing. A the vehicle interior 2 facing visible side 5 of the luminous element 1 is formed by a protective layer 6 that with the front 4 the semitransparent layer 3 connected and completely covered. One the visible side 5 of the luminous element 1 forming surface of the protective layer 6 is completely smooth and stepless. The protective layer 6 is at least partially translucent and can be formed for example by a scratch-resistant varnish. In some embodiments, the protective layer is 6 a thin, translucent stone or wood layer.

A backside 7 the semitransparent layer 3 has a recess 8th on. The depression 8th is rectangular in the illustrated cross section, so that through the recess 8th two parallel side walls 9 . 9 ' be formed. In addition, through the depression 8th a first region 10 in which the semitransparent layer 3 has a small thickness d ₁ , and a second region 11 in which the semitransparent layer 3 has a greater thickness d ₂ , formed. The thickness d ₁ in the first region 10 is for example 200 microns and the thickness d ₂ in the second region 11 is for example 1500 microns.

The light element 1 also includes a translucent carrier 12 that with the back 7 the semitransparent layer 3 is connected and the back 7 the semitransparent layer 3 in the first region 10 and in the second region 11 covered. In addition, the carrier fills 12 the depression 8th completely off. The carrier 12 may also be an injection molded part of PMMA, PC or polypropylene, in particular milky polypropylene, and for example together with the semitransparent layer 3 be prepared in a two-component injection molding process. On a back 13 of the carrier 12 are reinforcing ribs 14 . 14 ' arranged, which is the lighting element 1 give extra stability.

Behind the back 13 of the carrier 12 is a light source 15 arranged, which is shown only schematically in the figure shown. Typically, it is the light source 15 a point light source or a planar light source, for example an array of light-emitting diodes, which is the semitransparent layer 3 backlit flat. In another embodiment, the light source is a light guide in which light from a more remote active radiation source, e.g. B. a light emitting diode, can be initiated.

Due to the larger thickness d _{2 of} the semitransparent layer 3 in the second region 11 must be from the light source 15 in the vehicle interior 2 radiated light in the second region 11 a larger path through the semitransparent layer 3 return. The semitransparent layer 3 points in the first region 10 and in the second region 11 the same absorption coefficient of, for example, 1 mm ^-1 . Therefore, the light passes through the second region 11 absorbed more strongly than when passing through the first region 10 and when the light source is on, the first region appears 10 from the vehicle interior 2 looked brighter than the second region 11 , Due to the different thicknesses d ₁ , d ₂ corresponds to the transmittance in the first region 10 for example, one hundred times the transmittance in the second region 11 equivalent.

The side walls 9 and 9 ' the depression 8th can be completely smooth, so this from the light source 15 radiated and on the side walls 9 . 9 ' reflect the incoming light almost completely. In addition, the refractive index of the carrier is 12 greater than the refractive index of the semitransparent layer 3 , so that a total reflection on the sidewalls 9 . 9 ' can be achieved in low light. In other possible embodiments, the side walls 9 . 9 ' for example, have a reflective coating.

An area 16 the back 7 the semitransparent layer 3 in the first region 10 is roughened, so by the light source 15 emitted light in a wide solid angle in the vehicle interior 2 is emitted. The mean square roughness in this area 16 is for example 15 microns. Additionally, in the semitransparent layer 3 in the first region 10 light-scattering pigments, for example TiO ₂ , are introduced. In addition, the protective layer may be in one with the first region 10 overlapping region have light-scattering pigments. A thickness of the carrier 12 in the recess, for example, is 2 mm. The carrier 12 has a transmittance in this range which is greater than the transmittance of the semitransparent layer 3 in the first region 10 , However, the carrier can 12 include light scattering material, for example inclusions of specular materials.

2 shows a plan view of a region of the luminous element 1 from the vehicle interior 2 from when the light source is turned on 15 , Recurring features are given the same reference numerals in this and the following figure. On the visible side 5 of the luminous element 1 two letters are perceptible as luminous surfaces. The contours of the letters correspond to a shape of the first region 10 , In areas of the second region 11 correspond, the light element appears dark.

In 3 is a plan view of the same area of the lighting element 1 with the light source switched off 15 shown. Also in the vehicle interior 2 prevailing ambient brightness is the first region 10 and the second region 11 imperceptible to the viewer and the viewing side 5 of the luminous element 1 appears as a visually homogeneous surface.

Only features disclosed in the embodiments of the various embodiments can be combined and claimed individually.

Claims (13)

Light element ( 1 ) for use in a vehicle interior ( 2 ) comprising a semitransparent layer ( 3 ) with a front side ( 4 ) and a back ( 7 ) and one behind the semitransparent layer ( 3 ) arranged light source ( 15 ), the front side ( 4 ) of the semitransparent layer ( 3 ) is even, characterized in that the back ( 7 ) of the semitransparent layer ( 3 ) at least one depression ( 8th ), so that the semitransparent layer ( 3 ) at least a first region ( 10 ) having a first thickness (d ₁ ) and at least one second region ( 11 ) having a second thickness (d ₂ ), wherein the first thickness (d ₁ ) is less than the second thickness (d ₂ ) and the first region (d ₂ ) 10 ) from the light source ( 15 ) emitted light and the second region ( 11 ) from the light source ( 15 ) and thereby transmit less light than the first region ( 10 ). Light element ( 1 ) according to claim 1, characterized in that the semitransparent layer ( 3 ) is formed in one piece. Light element ( 1 ) according to one of claims 1 or 2, characterized in that a transmittance in the first region ( 10 ) at least ten times a transmittance in the second region ( 11 ) corresponds. Light element ( 1 ) according to one of claims 1 to 3, characterized in that the second thickness (d ₂ ) is greater by at least 200 microns than the first thickness (d ₁ ). Light element ( 1 ) according to one of claims 1 to 4, characterized in that the first thickness (d ₁ ) at least 50 microns and / or that the second thickness (d ₂ ) is at most 5 mm. Light element ( 1 ) according to one of claims 1 to 5, characterized in that the semitransparent layer ( 3 ) Contains polymethylmethacrylate and / or polycarbonate. Light element ( 1 ) according to one of claims 1 to 6, characterized by a transparent carrier ( 12 ) between the semitransparent layer ( 3 ) and the light source ( 15 ) is arranged. Light element ( 1 ) according to claim 7, characterized in that the carrier ( 12 ) for transmitting and / or scattering the light source ( 15 ) emitted light is set up. Light element ( 1 ) according to one of claims 7 or 8, characterized in that the carrier ( 12 ) the at least one depression ( 8th ). Light element ( 1 ) according to one of claims 1 to 9, characterized by a light-permeable protective layer ( 6 ), the front ( 4 ) of the semitransparent layer ( 3 ) at least partially covered. Light element ( 1 ) according to one of claims 1 to 10, characterized in that the rear side ( 7 ) of the semitransparent layer ( 3 ) in the first region ( 10 ) is at least partially roughened. Light element ( 1 ) according to one of claims 1 to 11, characterized in that the semitransparent layer ( 3 ) in the first region ( 10 ) has light-scattering pigments. Light element ( 1 ) according to one of claims 1 to 12, characterized in that side walls ( 9 . 9 ' ) of the depression ( 8th ) are at least partially reflective.

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