FR2838669A1 - Production of a control panel, especially for automobile dashboards, comprises placing a flexible film including an electroluminescent layer into a mold and injecting the material of the control panel into the mold - Google Patents

Abstract

Production of a control panel comprises placing a flexible film including an electroluminescent layer (3) into a mold, closing the mold, and injecting the material of the control panel into the mold so that the material is molded onto the film.

Description

when cutting.

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  Method for manufacturing a control panel intended in particular

  to equip the dashboard of a vehicle.

  The field of invention is that of the design and realization of

  control panels, of the type fitted to the cockpits of vehicles.

  More precisely, the invention relates to a method of manufacturing by molding a control panel integrating various graphic elements or symbols

likely to be illuminated.

  For the lighting of such graphic elements or symbols, a conventional solution consists in providing as many bulbs as there are symbols or graphic elements to be lit, these bulbs being positioned at the rear of the

control panel.

  Such a technique has the drawback of requiring the mounting of a network of electric wires for the supply of the bulbs, which induces

  consequent assembly time as well as the use of a specialized maneuver.

  The bulbs also have the drawback of not providing homogeneous lighting of the control panel, parasitic shadow zones which can

  especially appear and harm the aesthetics of it.

  In addition, these bulbs, which can be present in relatively large numbers, occupy a fairly large space behind the control panel. However, the current trend, in particular in the automotive industry, is rather towards the search for solutions allowing to obtain space savings, even minimal, especially at the level of all parties.

  constituting the passenger compartment of a vehicle.

  Lighting using bulbs on a control panel, integrating the

  dashboard of a vehicle, therefore goes against this trend.

  A technique is also known which consists in making various graphic elements or symbols of a control panel luminous, using an electroluminescent film.

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  According to this technique, the electroluminescent film is assembled by gluing to

control panel.

  This technique has many advantages (saving space, ease of implementation, speed of implementation ...) but also involves certain drawbacks. Thus, the holding of the glue joining the film to the control panel sometimes degrades in the more or less long term, possibly going as far as to cause the separation of the electroluminescent film, which obviously does not

  operation and / or deteriorate the presentation of the control panel.

  In addition, it turns out to be difficult or even impossible to glue the electroluminescent film on a control panel having left shapes in dimensional trots. However, such forms are currently very sought after by

consumers.

  The invention particularly aims to overcome the drawbacks of art

1 5 previous.

  More precisely, the invention aims to propose a manufacturing process which allows an electroluminescent film to be associated with a control panel in a way that is easier and more durable than by the technique of the prior art. The invention also aims to provide such a method which makes it possible to obtain homogeneous lighting of a control panel, including when

  this presents a plurality of light zones.

  The invention also aims to provide such a method which allows the realization of a control panel having complex shapes or

  stylized, such as in particular curves in two dimensions.

  These objectives, as well as others which will appear thereafter, have been achieved thanks to the invention which relates to a method of manufacturing by molding a control panel intended in particular to equip the dashboard of a vehicle comprising the following steps:

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  - depositing in a mold at least one flexible film at least partially integrating an electroluminescent layer; - injecting the material into said control panel into said previously closed mold, so that said material is molded onto said film. It will be noted that it will be possible to use, in the context of such a process, different flexible electroluminescent films, in particular those formed by a support on

  which is screen printed with a conductive ink.

  The method according to the invention provides a technique for assembling an electroluminescent film and a control panel which can be set up.

  works faster than previous techniques.

  We can in this way, we integrate homogeneous lighting means to a control panel, including if it has complex shapes and

  stylized with in particular curves in two dimensions.

  In addition, the assembly by overmolding of the dashboard body on the electroluminescent film is more gable and more durable than the assembly by gluing.

according to the prior art.

  The method according to the invention also has the advantage of avoiding

  long preparation and mounting operations for the control panel.

  Indeed, such a process makes it possible to manufacture a facade of a switchboard

  controls forming a monobloc assembly ready to be mounted in a vehicle.

  The method according to the invention also provides the following advantages compared to the prior art: - space saving: the film has substantially the same thickness as the decor, namely approximately 0.3 mm; - no heat generation; - low consumption;

- wide choice of colors.

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  According to an advantageous solution, said control panel comprises a layer of a hot-melt material forming a support for said electroluminescent layer. This improves the reliability and the resistance of the assembly between the control panel and the film comprising the electroluminescent layer: at the moment when the material of the control panel is injected into the motile, the temperature thereof generates an interface of contact particularly suitable for obtaining a

durable assembly.

  According to a preferred solution, at least one core is positioned in said fac mold, at least one reserve has to be provided in said material at said board.

of orders.

  According to a first approach, said core cooperates with said film and said mold so as to form a "blistering" in said film, that is to say a blister allowing to receive a contactor which can be actuated by

simple touch of the finger on it.

  These "blisters" are actually used more and more on vehicle control panels. Their lighting would be difficult, if not impossible,

  with the techniques of the prior art.

  According to another approach, the method comprises a step of dep80t of a conductive material in at least one of said reserves. In this case, said

  deposition step is preferably reali see by seri graphi e.

  The electrical connections necessary for supplying the electroluminescent layer are thus provided at predetermined locations, further facilitating the mounting on a vehicle of the assembly obtained with the

method according to the invention.

  According to a preferred solution, the method comprises an additional step

  for setting up a printed circuit, at the back of the control panel.

  Preferably, said elastomeric layer carries electrical connections intended to be connected to said conductive material deposited in said one or said reserves. s 2838669 In this case, the method comprises according to a first embodiment a step of mi is in place of an el astomeric web ntermediai re between the lad i te elastomeric web and said hot melt material, said intermediate web comprising at least one button coinciding with a conductive area carried by said intermediate sheet, said button being capable of cooperating with said blister to form an electrical contact, through said area

  conductive, with said main elastomeric sheet.

  The actuators of the control panel can thus also be

directly integrated into the whole.

  Advantageously, said conductive zone comprises at least one patch

of carbon.

  According to another embodiment, said film carries, at the level of said or said shutters, a contactor capable of being brought into contact with said

main tablecloth.

  Other embodiments of bringing the actuator (s) into contact with the

  control panel wind however possible without departing from the scope of the invention. In either embodiment, said hot-melt layer on said film is. according to a first approach completely coated with said electroluminescent layer. According to another approach, said hot-melt layer is coated with said electroluminescent layer only in one or more predetermined sectors. In this case, the said sector (s) preferably coincide with the

  position of one or more push buttons.

  We can in this way, we get a lighting by the back of the buttons,

  producing a particularly aesthetic effect.

  According to this approach, said film has at least one tear-off zone coinciding with said one or more predetermined sectors, said zone being intended

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  to be torn for example when mounting a button on the control panel. The electroluminescent film could however, according to another embodiment, be cut out prior to its placement in the mold in predetermined locations. Still according to this approach, the said predetermined sector or sectors are wind

  preferably bordered by at least one light baffle.

  In this way, it is possible to effectively limit the diffusion of the lighting to a desired area, in this case the rear of the push buttons. This provision is however applicable to other constituent parts of a control panel. Whatever the embodiment and / or the approach of the invention, the

  molding is advantageously carried out under pressure.

  Other characteristics and advantages of the invention will become more apparent

  clearly on reading the following description of two embodiments

  preferentials of the invention, given by way of illustrative and nonlimiting example, and of the drawings among which: FIG. 1 represents in section part of a control panel integrating an actuator in the form of blister, obtained with the process according to the invention; - Figure 2 shows in section part of a control panel incorporating a push button type actuator, obtained with the method

according to the invention.

  According to the embodiment illustrated in FIG. 1, a control panel intended to equip the dashboard of a vehicle comprises an opaque hot-melt plastic material 1 secured to a flexible film comprising

  a screen-printed layer 2 and an electroluminescent layer 3.

  According to the invention, such a control panel is manufactured by injecting the plastic material 1 into a mold in which the flexible film comprising the support 2 and the electroluminescent layer 3, the material has previously been deposited.

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  plastic 1 being overmolded on the film at the end of the presslon molding operation. To form the reserves 4 and 5 as represented in FIG. 1, wind cores positioned in the mold before injection of the plastic material (it is also possible according to another embodiment that the imprint of the

  mold is itself conformed to obtain these reserves).

  In reserve 5, a conductive material (not shown) is deposited by screen printing so as to constitute an electrical contact as will be described

thereafter.

  According to this embodiment, there is reported by overmolding, behind the plastic I of the control panel, a printed circuit 6, carry electrical connections 61 intended to be connected to the conductive material deposited in the reserve 5. These electrical connections 61 wind intended to supply the

electroluminescent layer 3.

  This printed circuit 6 is also intended to conduct the electricity at the level of a button 71 under which is fixed a carbon pellet 711. For this purpose, an intermediate elastomeric sheet 7 is placed during manufacture between the circuit

  print 6 and plastic 1.

  The button 71 and the carbon disc 711 are carried by the tablecloth

elastomer 7.

  Note that the film comprising the support 2 and the electroluminescent layer 3 forms at the level of the reserve 4 a blister 8, that is to say a blister in the front, of the control panel that can be enforced

  slightly and which returns to its initial shape when the pressure is released.

  A pressure on the blister 8 causes a displacement of the button 71 carried by the ply 7 towards the printed circuit 6, until the pad 711 comes to the

  contact of the printed circuit 6 which then transmits the electrical power to it.

  With reference to FIGS. 2 and 3, the control panel obtained with the method according to the invention comprises a push button 9, installed in a

reserve 4a.

  As it clearly appears in FIG. 2, the hot-melt layer 1 of the control panel is coated with the electroluminescent layer 3 only in certain sectors, space by screen-printed segments 10 no

electroluminescent.

  The sector 31 of the electroluminescent layer coincides with the position of the press button 9, producing, when the electroluminescent layer is

  supplied with electricity, lighting by the back of push button 9.

  When producing such a control panel, the electroluminescent film has a tear-off zone which is torn apart by

  enforcement of part 32 of button 9.

  By an opaque molding or a screen printing of the appropriate film, an area obstructing the light will be managed so as to avoid any light leakage

between button 9 and the university, ade.

l

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Claims (13)

  1- Method of manufacturing by molding a control panel intended in particular to equip the dashboard of a vehicle, characterized in that it comprises the following stages: - depositing in a mold at least one flexible film integrating at least partially an electroluminescent layer (3); - injecting the material into said control panel into said previously closed mold, so that said material is overmolded on said film.   2 - Method according to claim l, characterized in that said control panel comprises a layer of a hot-melt material (I) forming   support of said electroluminescent layer (3).   3 - Method according to claims I and 2, characterized in that at least one   core is positioned in the said mold so as to provide at least one reserve   (4), (5) in said material to said control panel, behind said film.   4 - Method according to claim 3, characterized in that said core cooperates   with said film and said mold so as to form a blister (8) in said film.   - Method according to claim 3, characterized in that it comprises a step   depositing a conductive material in at least one of said reserves (4).   6 - Method according to claim 5, characterized in that said deposition step is produced by screen printing.   7 - Method according to any one of claims 1 to 6, characterized in that it   includes an additional step for setting up a printed circuit (6), The back of the control panel.   8 - Method according to claim 7, characterized in that said printed circuit (6) carries electrical connections (61) intended to be connected to said material   conductor deposited in said reserve (s) (5).   9 - Method according to claims 7 and 8, characterized in that it comprises a   step of setting up an intermediate elastomeric sheet (7) between said 2838669   printed circuit (6) and said hot-melt material (1), said intermediate sheet (7) comprising at least one button (71) coinciding with a conductive zone (711) carried by said intermediate sheet (7), said button (71) being capable of cooperating with said blister (8) to form an electrical contact, via said conductive zone (711), with said elastomeric sheet main (6).   - Method according to claim 9, characterized in that said zone   conductive (711) comprises at least one carbon pellet.   11 - Method according to claims 7 and 8, characterized in that said film   carries, at the audit or said blister (8) level, a contactor capable of being   brought into contact with said main sheet.   12 - Method according to any one of claims 1 to 11, characterized in that   that said hot-melt layer (1) is completely coated with said layer electroluminescent (3).   IS 13 - Method according to any one of claims 1 to 11, characterized in that   said hot-melt layer (1) is coated with said electroluminescent layer   (3) only in one or more predetermined sectors (31).   14 - Method according to claim 13, characterized in that the or said sectors (31) coincide with the position of one or more push buttons (9). - Method according to claim 14, characterized in that said film has at least one tear zone coinciding with said one or said sectors predetermines (31).   16 - Method according to any one of claims 13 to 1S, characterized in that   that the said predetermined sector or sectors (31) are bordered by at least one baffle light (11).   17 - Method according to one of claims 1 to 16, characterized in that said