Vehicle trim component and associated manufacturing process

Abstract

Vehicle trim element and associated manufacturing process. This vehicle trim element (10) comprises a translucent panel (14), intended to cover a light source (12) configured to generate polarized radiation, in an overlap region (20). The translucent panel (14) comprises a birefringent layer (22) made of an injected thermoplastic material, defining principal axes (B) of refractive indices of the translucent panel (14). The principal axes of the refractive indices are essentially constant over the entire overlap region (20). Figure for the abbreviation: Figure 1

Description

Title of the invention: Vehicle trim element and associated manufacturing process

[0001] The present invention relates to a vehicle trim element. The invention further relates to a method for manufacturing such a vehicle trim element.

[0002] In the field of vehicle trim components, it is known to equip certain trim components with light sources, such as display screens. These light sources allow, for example, the illumination of a vehicle's interior and / or the display of information within the passenger compartment.

[0003] In order to protect such light sources, it is also known to equip these trim elements with translucent panels, preferably transparent, covering the light sources. Such translucent panels are, for example, made of injected thermoplastic material, notably because of the low production cost of such panels, but also because of the physical properties of these materials, such as their good impact resistance.

[0004] The anisotropy of the refractive index of certain of these injected thermoplastic materials sometimes creates birefringence when these materials are illuminated by a polarized light source; that is, the light spectrum passing through depends on the polarization of the incident light. Translucent panels formed using such materials, called birefringents, define principal axes of refractive index at every point of the panel; that is, if the polarization of the incident light is parallel to one of these principal axes, the light passing through maintains the same polarization direction.

[0005] Moreover, light sources sometimes generate polarized light, for example when the light sources are display screens, such screens being generally equipped with polarizing filters, like liquid crystal displays.

[0006] The use of panels made of such a material as above, combined with such light sources, may then prove problematic.

[0007] Indeed, observing, through polarized lenses (such as polarized sunglasses), screens generating polarized light and covered with a plate made of a birefringent material, can result in aberrations in the colors perceived by the observer. For example, white light emitted by such a light source may appear iridescent to an observer viewing this source through a plate made of a birefringent material and polarized lenses.

[0008] This can be disturbing for the user, in particular due to a visually unsatisfactory aspect, and can even prove dangerous when the light source is a display screen for information relating to driving the vehicle.

[0009] Thus, one aim of the invention is to propose a filling element that is robust, easy to manufacture and inexpensive, while being minimally disturbing to an observer of that element.

[0010] To this end, the invention relates to a vehicle trim element, comprising a translucent panel, intended to cover a light source configured to generate polarized radiation, in an overlap region, the translucent panel comprising a birefringent layer made of an injected thermoplastic material, defining principal axes of refractive indices of the translucent panel, the principal axes of the refractive indices being essentially constant over the whole of the overlap region.

[0011] The use of a translucent, injection-molded thermoplastic panel whose principal axes of refractive indices are essentially constant over the entire overlap region is particularly advantageous, especially when used in relation to polarized light sources. Indeed, the radiation emitted by such light sources is not affected by the anisotropy of the refractive indices of the translucent panel. This makes it possible to use robust and inexpensive thermoplastic panels without them causing interference to an observer of the element.

[0012] According to other advantageous aspects of the invention, the filling element comprises one or more of the following characteristics, taken individually or in any technically feasible combination:

[0013] - the injected thermoplastic material is polycarbonate;

[0014] - the trim element further comprises a light source configured for generate a light radiation polarized along a direction of polarization, the translucent panel covering the light source so that the translucent panel is traversed by the light radiation, the principal axes of the translucent panel being parallel or perpendicular to the direction of polarization of the light radiation over the entire overlap region;

[0015] - the light source includes a display screen; and

[0016] - the filling element further comprises a support arranged around the source luminous, the translucent panel also covering at least partially the support in an overflow area.

[0017] The invention relates to, in addition to, a method for manufacturing a trim element as described above, comprising a step of injecting a thermoplastic material to form the translucent panel, using at least one injection inlet, the material thermoplastic being injected by defining principal axes of refractive indices and by defining an injection front, the injection front keeping a substantially constant orientation throughout the injection, in the overlap region.

[0018] According to other advantageous aspects of the invention, the manufacturing process for a trim element comprises one or more of the following characteristics, taken individually or in any technically feasible combination:

[0019] - at least one injection inlet is flared to form an injection sheet, a ratio of a width to a height of an injection opening of the injection layer being greater than 5;

[0020] - the injection of the thermoplastic material to form the translucent panel is achieved using a plurality of injection inlets, arranged on the same side of the translucent panel formed;

[0021] - the gap between the injection openings of at least two injection layers ad underlying is less than 10 mm; and

[0022] - the thermoplastic material injection step is carried out sequentially by the plurality of injection inlets, at least one of the injection inlets being blocked so as not to inject thermoplastic material during the injection of thermoplastic material by at least one of the other inlets during at least one sequence of the injection of thermoplastic material to form the translucent panel.

[0023] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which:

[0024] [Fig-1] [Fig. 1] is a schematic perspective representation of a trim element according to the invention, in which the trim element comprises a light source and a translucent panel, the light source and the translucent panel being shown separated from each other;

[0025] [Fig.2] [Fig.2] is a schematic front view representation of another element of filling according to the invention, during the manufacture of this element; and

[0026] [Fig.3] [Fig.3] is a flowchart representing different stages of manufacturing of a trim element according to the invention.

[0027] In the following description, the "direction of polarization" of a light radiation means the direction adopted by the oscillations of the electric field of the light radiation within a plane perpendicular to a direction of propagation of said light radiation.

[0028] In the following description, the term "axis of refraction" means one of the principal axes of the refractive index of a translucent material, that is to say, one of the ordinary or extraordinary axes of the ellipse characterizing the refractive index properties. fraction of a translucent material. In a particular embodiment, "axis of refraction" means the principal optical axis of the translucent material, or extraordinary axis of the material, that is, the axis along which the refractive index does not depend on the polarization of radiation passing through the translucent element.

[0029] In the remainder of this description, the term "translucent" is used to describe any object that allows light rays to pass through it. The term "transparent" is used in the description to describe any object that allows light rays to pass through it without scattering them. It will therefore be understood that, as used in this description, the term "transparent" designates a specific case of the term "translucent".

[0030] With reference to figures 1 and 2, a trim element 10 comprises a translucent panel 14. The trim element 10 includes, for example, a light source 12. The trim element 10 further includes, for example, a support 16.

[0031] The trim element 10 is for example intended to be installed in the passenger compartment of a vehicle, such as for example a motor vehicle (not shown).

[0032] The trim element 10 is, in particular, for example, a vehicle dashboard or a portion of a vehicle dashboard. Alternatively, the trim element 10 is a center console, a door panel, or a seat.

[0033] The light source 12 is configured to generate light radiation L polarized along a polarization direction P. In particular, all the light radiation L generated by the light source 12 is polarized along the polarization direction P. In other words, the polarization of the light radiation L is constant for any light ray generated by the light source 12 and oriented along the polarization direction P. The polarization direction of the light source 12 is thus understood to be the polarization direction P of the light radiation L that the light source 12 is configured to emit.

[0034] In particular, and as illustrated in Figures 1 and 2, the light source 12 delimits, for example, an illumination region 18. The light radiation L emitted by the light source 12 over the entire illumination region 18 is then polarized along the polarization direction P. The polarization direction P is, in other words, constant over the entire illumination region 18.

[0035] The light source 12 includes, for example, a display screen. The light source 10 is, for example, a display screen, and is, for example, a liquid crystal display screen equipped with a polarizing filter.

[0036] As illustrated in [Fig.1], the translucent panel 14 is intended to cover the light source 12 in an overlap region 20. The overlap region 20 is therefore a region of the translucent panel 14 on which the translucent panel 14 is intended to cover the light source 12.

[0037] The translucent panel 14 is intended to allow light radiation to pass through, for example emitted by the light source 12. The translucent panel 14 is, for example, transparent.

[0038] In a particular embodiment, when the light source 12 delimits an illumination region 18, the cover region 20 is intended to completely cover the illumination region 18. When the trim element 10 includes a light source 12, the cover region 20 is, for example, superimposed on the illumination region 18, the contours of the cover region 20 corresponding, for example, substantially to the contours of the illumination region 18.

[0039] In the example of [Fig. 1], the light source 12 and the translucent panel 14 are separated from each other. In a particular embodiment, the translucent panel 14 extends at least partially over the light source 12, the overlapping region 20 extending, for example, entirely over the illuminated region 18.

[0040] As illustrated in [Fig.1], the translucent panel 14 is intended to cover the light source 12 so that the translucent panel 14 is traversed by the light radiation L.

[0041] As illustrated in [Fig. 1], the translucent panel 14 comprises a birefringent layer 22 in which one refractive index is anisotropic. The birefringent layer 22 is made of an injected thermoplastic material and defines principal axes B of refraction of the translucent panel 14 at every point of the layer 22. One of the principal axes B of refraction is shown in [Fig. 1]. The principal axes B are essentially constant over the entire overlap region 20, i.e., the orientation of the principal axes B is essentially constant over the entire overlap region 20.

[0042] In the variant illustrated in [Fig.1], the translucent panel 14 is constituted by the birefringent layer 22. In a variant not illustrated, the translucent panel 14 comprises a plurality of superimposed birefringent layers defining the principal axes of refraction B. Alternatively, or in addition to the variants previously presented, the translucent panel 14 comprises at least one isotropic layer superimposed on the birefringent layer(s) (not illustrated).

[0043] The principal axes B of the translucent panel 14 are, for example, parallel or perpendicular to the polarization direction P of the light radiation over the entire overlap region 20. The principal refractive axes B of the refractive indices of the translucent panel 14 are, in addition, each, for example, perpendicular to a direction of propagation of the light radiation, corresponding, for example, to a thickness direction of the translucent panel 14.

[0044] The injected thermoplastic material forming the birefringent layer 22 is, for example, polycarbonate. Polycarbonate comprises, for example, groups phenyl giving the birefringent layer 22 its birefringent character.

[0045] Each phenyl group defines in particular a phenyl group orientation, the orientation of the phenyl group being for example determined by the orientation of the radical of the phenyl group.

[0046] The orientation of the phenyl groups in the birefringent layer 22, i.e., for example, the average orientation of these phenyl groups, defines, for example, one of the principal axes B. The orientation of the phenyl groups is, for example, parallel or perpendicular to the polarization direction P of the light radiation L over the entire birefringent layer 22. Furthermore, the orientation of the phenyl groups is, for example, perpendicular to the propagation direction of the light radiation L. It will be understood in particular that at least 80% of the phenyl groups in the polycarbonate forming the birefringent layer 22 are oriented such that their orientation forms an angle of less than 15° with the polarization direction P or with a direction perpendicular to the polarization direction P.

[0047] In particular, the orientation of the phenyl groups of the birefringent layer 22, that is to say for example the average orientation of these phenyl groups, defines one of the principal axes B of the translucent panel 14 formed by the birefringent layer 22.

[0048] As illustrated in Figures 1 and 2, the support 16 is arranged for example around the light source 12. The translucent panel 14 then covers for example at least partially the support 16 in an overflow region 24.

[0049] The overflow region 24 extends for example around the cover region 20, in continuity with the cover region, the cover region 20 and overflow region 24 having come from material.

[0050] As illustrated in [Fig.2], one of the principal axes B of the translucent panel 14 is not necessarily parallel or perpendicular to the polarization direction P of the light radiation on the spillover region 24.

[0051] A method 100 for manufacturing a trim element 10 as described above will now be presented.

[0052] As will be described in more detail later, such a process 100 is for example implemented using a manufacturing tool 40 comprising for example an injection unit 42 and a mold 44, the injection unit 42 comprising for example at least one injection inlet 46 of a thermoplastic material to be molded into the mold 44.

[0053] The process 100 includes an injection step 120. As illustrated in [Fig.3] the process 100 includes for example a supply step 110 preceding the injection step 120 and includes for example a covering step 130 subsequent to the injection step 120.

[0054] During the supply step 100, a light source 12 as described above is provided, for example. In addition, during this step, a support 16 is provided, for example. In one embodiment, the support 16 and the light source 12 are provided simultaneously, the support 16 being, for example, arranged around the light source 12 and being, for example, attached to the light source 12. In another embodiment, the support 16 is provided subsequently and the light source 12 is attached to the support after the support 16 has been covered by the translucent panel 14.

[0055] During the injection step 120, a thermoplastic material is injected, for example with the manufacturing tool 40. The thermoplastic material is, for example, injected into the mold 44 through at least one injection inlet 46. In the example of [Fig.2], the plastic material is, for example, overmolded onto the support 16 and the light source 12 to form the translucent panel 14. By way of example, the support 16 and the translucent panel 14 are produced by two-component injection, for example known as "2K injection".

[0056] The thermoplastic material is for example polycarbonate and is injected to form the translucent panel 14, and in particular to form the birefringent layer 22.

[0057] The thermoplastic material is injected by defining the principal axes B, the material being in particular injected so that the defined principal axes B are constant over the overlap region 20 of the translucent panel 14 formed.

[0058] The thermoplastic material is further injected so that the principal axes B of the cover region 20 of the translucent panel 14 formed are parallel or perpendicular to the direction of polarization P of the light radiation L generated by the light source 12 which the translucent panel 14 is intended to cover or which it covers, and for example further perpendicular to the direction of propagation of this radiation.

[0059] In the embodiment described below, the covering step 130 takes place simultaneously with the injection step 120, the translucent panel 14 being, for example, overmolded onto the light source 12. Alternatively, the covering step 130 is carried out after the injection step 120, the translucent panel 14 formed during the injection step 120 then being, for example, attached, for example, to the light source 12 during the covering step 130.

[0060] During the covering step 130, the light source 12 is for example covered by the translucent panel 14 in the covering region 20 of the translucent panel 14.

[0061] During the covering step 130, the translucent panel 14 covers, for example, the light source 12 so that the translucent panel 14 is traversed by the light radiation L generated by the light source 12. The thermo-material plastic is then injected so that the translucent panel 14 formed covers the light source, in particular in an overlap region, the light radiation L emitted by the light source passing through said translucent panel 14 and in particular the overlap region 20.

[0062] The translucent panel 14 covers in particular the light source 12 so that the principal axes B of the translucent panel 14 are parallel or perpendicular to the polarization direction P of the light radiation L over the entire overlap region 20.

[0063] In particular, when the thermoplastic material injected to form the translucent panel 14, and in particular the birefringent layer 22, is polycarbonate comprising phenyl groups, the translucent panel 14 covers the light source 12 such that the orientation of the phenyl groups forming the birefringent layer 22 is parallel or perpendicular to the polarization direction P of the light radiation L over the entire overlap region 20. In addition, the orientation of the phenyl groups is perpendicular to the direction of propagation of the light radiation.

[0064] The thermoplastic material is in particular injected so that the phenyl groups of the birefringent layer 22 forming the translucent panel 14 are oriented parallel or perpendicular to the polarization direction P of the light radiation L over the entire overlap region 20.

[0065] During step 120 of thermoplastic material injection, the thermoplastic material is injected, defining an injection front 48. The injection front 48 corresponds to the advance front of the injected thermoplastic material within the mold 44 during its injection. The injection front thus evolves within the mold 44 throughout the injection step 120 until the translucent panel 14 is obtained.

[0066] The injection front in particular maintains a substantially constant orientation throughout the injection in the overlap region 20.

[0067] As illustrated in [Fig.2], the injection front 48 is for example substantially parallel or perpendicular, in the overlap zone 20, to the polarization direction P of the light radiation L, throughout the injection ([Fig.2] representing the injection front 48 at a given time during the injection).

[0068] The injection unit 42 further comprises, for example, a plurality of injection inlets 46, arranged on the same side of the mold 44, i.e., on the same side of the formed translucent panel 14. The step 120 of injecting the thermoplastic material is then carried out using the plurality of inlets 46.

[0069] As illustrated in the embodiment of [Fig. 2], the injection inlets 46 configured to inject the overlap region 20, i.e., the inlets 46 through which the thermoplastic material forming the overlap region 20 exits, are for example substantially aligned along an injection axis IA. In particular, the injection axis IA is median to these inputs 46 and is parallel or perpendicular to the polarization direction P of the light radiation L intended to cross the injected overlap region 20.

[0070] Furthermore, when the injection unit 40 comprises a plurality of injection inlets 46 forming an injection sheet as shown in [Fig.2], the gap E between the injection openings of at least two adjacent injection sheets is, for example, less than 10mm.

[0071] In particular, according to this embodiment, the entire set of injection layers are flattened and aligned along the same plane forming an IP injection plane.

[0072] In the example of [Fig.2], and in order to obtain a translucent panel 14 in which the principal axes B of the refractive indices of the translucent panel 14 are parallel or perpendicular to the polarization direction P of the light radiation L over the entire overlap region 20, the injection of the thermoplastic material is further carried out sequentially by the plurality of injection inlets 46.

[0073] In this example, at least one of the injection inlets 46 is closed so as not to inject thermoplastic material during the injection of thermoplastic material by at least one of the other inlets 46 during at least a first sequence of the injection of the thermoplastic material to form the translucent panel 14. All the inlets 46 are then, for example, subsequently released for the injection of thermoplastic material during a second sequence of the injection of the thermoplastic material to form the translucent panel 14.

[0074] In the example of [Fig. 2], three injection inlets are configured to inject the material forming the overlap region 20, these three inlets 46 being arranged on the same side of said overlap region 20, one of the inlets, referred to as the central inlet, being arranged between the other two inlets 46, referred to as the edge inlets. Two inlets 46 are further configured to inject material forming the overflow region 24 (see right side of [Fig. 2]).

[0075] During the first injection sequence, the thermoplastic material is injected only through the central inlet, the edge inlets being closed. During the second injection sequence, the edge inlets are opened, and the material forming the overlap region 20 is then injected simultaneously through the three aforementioned inlets.

[0076] In a particular embodiment, the flow rate of injected material is constantly regulated so that the thermoplastic material is injected by defining an injection front 48 as seen above, that is to say substantially parallel or perpendicular to the polarization direction P of the light radiation L, throughout the injection, in the overlap zone 20.

Claims

Demands

1. Vehicle trim element (10), comprising a translucent panel (14), intended to cover a light source (12) configured to generate polarized radiation, in an overlap region (20), the translucent panel (14) comprising a birefringent layer (22) made of an injected thermoplastic material, defining principal axes (B) of refractive indices of the translucent panel (14), the principal axes of the refractive indices being essentially constant over the entire overlap region (20).

2. Filling element (10) according to claim 1, wherein the injected thermoplastic material is polycarbonate.

3. A trim element (10) according to claim 1 or 2, further comprising a light source (12) configured to generate light radiation (L) polarized along a polarization direction (P), the translucent panel (14) covering the light source (12) so that the translucent panel (14) is traversed by the light radiation (L), the principal axes (B) of the translucent panel (14) being parallel or perpendicular to the polarization direction (P) of the light radiation (L) over the entire overlap region (20).

4. Trim element (10) according to claim 3, wherein the light source (12) comprises a display screen.

5. A trim element (10) according to claim 3 or 4, further comprising a support (16) arranged around the light source (12), the translucent panel (14) further covering at least partially the support (16) in an overflow region (24).

6. Method (100) of manufacturing a trim element (10) according to any one of claims 1 to 5, comprising an injection step (120) of a thermoplastic material to form the translucent panel, using at least one injection inlet (46), the thermoplastic material being injected by defining principal axes (B) of the refractive indices and by defining an injection front (48), the injection front keeping a substantially constant orientation throughout the injection, in the overlap region (20).

7. A method (100) for manufacturing a packing element (10) according to claim 6, wherein at least one injection inlet (46) is flared to form an injection layer, a width-to-height ratio of an injection opening of the injection layer being greater than 5.

8. Method (100) of manufacturing a trim element (10) according to claim 6 or 7, wherein the injection of the thermoplastic material to form the translucent panel (14) is carried out using a plurality of injection inlets (46), arranged on the same side of the translucent panel (14) formed.

9. Method (100) of manufacturing a filling element (10) according to claim 8, taken in its dependence on claim 7, wherein the gap (E) between the injection openings of at least two adjacent injection layers is less than 10 mm.

10. Method (100) of manufacturing a trim element (10) according to claim 8 or 9, wherein the injection step (120) of the thermoplastic material is carried out sequentially by the plurality of injection inlets (46), at least one of the injection inlets (46) being closed so as not to inject thermoplastic material during the injection of thermoplastic material by at least one of the other inlets (46) during at least one sequence of the injection of the thermoplastic material to form the translucent panel (14).

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