DE10234125A1 - Illuminatable plastic injection molding, comprises a display function with a visible surface region, an electroluminescent film, and a second surface region - Google Patents

Abstract

An Illuminatable plastic injection molding (6) comprises a display function with a visible surface region (12), a film and a second surface region. The first region has an electroluminescence film (2). Conductors (3) are applied directly onto the second surface region, in order to provide the electroluminescence film with a voltage. The second surface is not visible. The first surface has a lacquer coating. The electroluminescence film has connection points (5). The molding is produced by molding the rear of the film with a metallizable thermoplastic in an injection mold, and applying a metal layer to form the conductors.

Description

The invention relates to an illuminable plastic injection molded part with a display function that has a first, visible surface area having a film and a second surface area, and a method for producing a plastic injection molded part an electroluminescent film.

From the DE 199 34 951 Such a multi-component plastic injection molding with a display function is known, which is designed in particular for use in a motor vehicle, for example as a display panel or push button. An illumination of the plastic injection molded part can be achieved by means of an additional light source. Such pushbuttons can be produced automatically by back-molding a film.

From the DE 100 01 796 C2 a circuit structure is known which is equipped with switches, for example push buttons of a silicone switch mat. To illuminate the switches, an electroluminescent layer is integrated in the circuit structure. The electroluminescent layer serves to illuminate a switch mat internally. The respective conductor tracks are also arranged in two different layers of the circuit structure. With such an arrangement, the light source is thus integrated into a printed circuit board.

From the EP 1 014 329 A1 is a self-luminous information symbol for installation in buildings, in which the lighting is carried out by means of an electroluminescent film. The electroluminescent film is inserted or glued between two plates. The electroluminescent film is supplied with voltage via a cable feed.

From application information ATI 1131 issued by Bayer AG " Spatial, injection-molded circuit carriers "it is known to manufacture plastic components according to the so-called 3-D MID technology. With the 3-D MID technology, surfaces of injection molded parts made of thermoplastic materials of almost any shape can simultaneously be used as carriers for electrical circuits and components The two-component injection molding process with subsequent selective metallization and the hot stamping of metal foils on injection-molded substrate surfaces are mentioned as processes for the production of 3-D MID components. Another process is the back-injection molding of foils structured with conductor tracks The film thus produced is then back-injected, in particular with a decorative print on one side and the circuit diagram on the other side of the film.

The object of the invention is a illuminated plastic injection molded part with a display function, in particular one designed as an operating part for a switching device Specify plastic injection molded part in which the lamp in the plastic injection molded part is firmly integrated and the inexpensive in high volume can be produced. Another object of the invention is a method for producing such a plastic injection molded part specify.

The first task is at an illuminable plastic injection molded part with a display function solved by that the first, visible surface area of the plastic injection molded part form-fitting electroluminescent film connected to the plastic injection molding has and directly on the second surface area of the plastic injection molded part Conductor tracks for the voltage supply of the electroluminescent film are upset. The plastic injection molded part is special as a control unit for a switching device or designed as a display panel. The plastic injection molded part according to the invention has the advantage that the lighting device directly into the Plastic injection molded part is firmly integrated. An assembly of the plastic injection molded part with a lighting device therefore. To ensure the voltage supply of the electroluminescent film, are still directly on a second surface area of the plastic injection molded part Conductor tracks for the voltage supply of the electroluminescent film applied. This eliminates the need about cable feeds to have to ensure a power supply. Made in a single molded part a control panel can thus be realized in a plastic material, that contains both the lighting unit and the ones necessary for the voltage supply Interconnects. The plastic injection molded part can be automated can be produced, which simplifies the assembly considerably.

In a special embodiment it is provided that the second surface area on which the conductor tracks are arranged as an invisible surface of the display panel or the control panel is designed. This configuration has the advantage that the visual appearance of the visible area of the Plastic injection molded part is not disturbed by conductor tracks.

In a further embodiment it is provided that the visible surface area of the plastic injection molded part is at least partially coated. This configuration allows the plastic injection molded part to be adapted to its installation environment on painted surfaces. If the plastic injection molded part is, for example, the control panel of a motor vehicle component, the surface of the control panel can les can be adapted to the surface condition of the corresponding control unit by the paint.

In another embodiment it is provided that the visible surface area of the plastic injection molded part at least partially has a galvanic metal coating. The galvanic metal coating is in particular a decorative coating designed so that in turn an adjustment of the visible surface of the plastic injection molded part to its installation environment.

In another embodiment it is provided that the plastic injection molded part has a symbol, by a light-tight partial coating of the electroluminescent film is limited. The symbol can be used to indicate to an operator which function is triggered with a corresponding control panel. For applications in the motor vehicle, it is particularly important that the The driver controls the individual controls correctly even in the dark can assign. By such a symbol that is illuminated by the electroluminescent film is reliable recognition and assignment even in night mode of the individual controls possible. Furthermore, about Appropriate lighting of the symbol also gives the driver a switching status be signaled.

In further configurations, it is provided that the conductor tracks connecting contacts of the electroluminescent film Connect the connection points of the plastic injection molded part at which the plastic injection molded part can be electrically connected to a printed circuit board is. The connection of the connection points of the plastic injection molded part with the circuit board can be done in particular by means of spring elements. This is a simple way of realizing an operating element possible. In particular, there is no need for additional lighting elements or Lichtleitelemente with the control panel and / or the circuit board connect.

• – Hinterspritzen der Elektrolumineszenzfolie mit einem metallisierbaren, thermoplastischen Kunststoffmaterial in einem Spritzgießwerkzeug,
• – Aufbringen einer Metallschicht auf linienförmige Bereiche des Kunststoffspritzgussteiles zur Herstellung von Leiterbahnen zu Anschlusskontakten der Elektrolumineszenzfolie.

A method according to the invention for producing a plastic injection molded part with an electroluminescent film has the following method steps:

• Back injection of the electroluminescent film with a metallizable, thermoplastic material in an injection mold,
• - Application of a metal layer on line-shaped areas of the plastic injection molded part for the production of conductor tracks to connection contacts of the electroluminescent film.

In a first step is by injecting the electroluminescent film a metallizable, thermoplastic material in an injection mold a molded plastic part is produced in which the electroluminescent film is intimately connected to the plastic material. Then be Applied directly to the plastic injection molded conductor tracks. The molded plastic part can thus be produced in an automated process with the electroluminescent film as the light source and also the conductor tracks getting produced. An otherwise common one labor-intensive assembly of a plastic injection molded part with a lighting device and the production of electrical contacts the lighting device over Cable or the like can thus be omitted. The procedure is therefore for Suitable for mass production of illuminable plastic injection molded parts.

In particular, in the process step injection of the electroluminescent film first Precast are made, after building up the metal layer the pre-molded part in a further injection mold with a further plastic material is encapsulated. Here you can in the two injection molding steps different plastic materials are used, but only such areas of the plastic injection molded part from a metallizable, thermoplastic material must be made with Conductor tracks are provided while other areas from a cheaper plastic material can be produced. This procedure is particularly important for large-volume plastic injection molded parts advantageous in which the electroluminescent film and the conductor tracks affect only a small area of the molded plastic part. In particular it is further provided that at least one of the conductor tracks is applied so that it over at least two surfaces inclined to each other. This gives great freedom in terms of the shape of the plastic injection molded part and the arrangement the connection contacts guaranteed.

In particular, it is also provided that that the electroluminescent film is three-dimensional before back injection is deformed. The electroluminescent film can be connected to a almost any three-dimensional design of the surface of the Plastic injection molded part to be adjusted.

In a further particular embodiment it is provided that the metallizable, thermoplastic material can be activated by laser and that the linear areas of the plastic injection molded part are first activated by means of a laser before the metal layer is applied. Laser-activatable, metallizable, thermoplastic plastic materials have metal particles in the plastic mass. Using a laser, the metal particles are exposed in the areas that are to be metallized by removing a small amount of the plastic material. Chemical electroplating (metal deposition, currentless) can then be used to apply a metal layer to the laser-activated areas for producing the conductor tracks. A metal layer applied in this way can subsequently be galvanically reinforced in particular. In this respect it is about that Application of metallic conductor tracks according to the well-known 3-D MID process.

To produce a light symbol the electroluminescent film or the injection molded part can be painted be, the coating of the electroluminescent film partially is removed again, in particular by means of a laser. By the Removal of the paint on the electroluminescent film can thus a light symbol can be made.

Analogous to painting, a PVD coating can also be used (Sputtering) in the visible surface area be provided. A metal coating produced in this way is then by means of of a laser partially exempted, so that the EL foil underneath as a symbol comes to light.

In a modified procedure to produce the conductor tracks can be used to build up the metal layer first a mask and then a metal coating on the unmasked areas be applied. If the conductor tracks are applied in this way, so can in particular by applying the metal coating in addition the production of the conductor track also a partially decorative coating of the Plastic injection molded part. In a single step can thus both the conductor tracks and the decorative coating be applied, which results in the saving of manufacturing steps Cost advantages result.

The invention is described below of embodiments and closer to the drawing explained. Show it:

1 2 shows a flow diagram of a first method variant,

2 different views of a button produced according to the first method variant,

3 2 shows a flow diagram of a second method variant,

4 different views of a key cap manufactured according to the second method variant.

The method for producing a plastic injection molded part in the form of a button for an operating element of a motor vehicle is described with reference to 1 explained. In method step S1, the electroluminescent film is first three-dimensionally deformed. The deformation of the electroluminescent (EL) film takes place in such a way that its surface design corresponds to the surface of the corresponding area of the key to be manufactured. In step S2, the EL film is placed in an injection mold. In step S3, the EL film is back-injected in the injection mold, with a form and material-fluid connection between the EL film and the plastic material. The plastic material used for the extrusion coating is a laser-activatable MID material such as, for example, "PBT MID" or "PA6.6T MID". On the film side, an adhesion promoter is applied as the last layer, which ensures good adhesion between the EL film and the MID material. By back-molding the EL film, a pre-molded part is produced which is designed in such a way that the surface areas for the conductor tracks to be applied later can be activated by an inscription laser or mask pulse laser between contact points of the EL film and contact points of the button to an outer circuit board. The contact point to the EL film is realized by exemptions in the film tool (slide).

2a shows the preform thus produced 1 with the EL film 2 , The pre-molded part is removed from the injection mold in step S4. Then, in step S5, the laser activation of those areas of the pre-molded part which are later to have the conductor track and the connection contacts takes place. Laser activation removes a small amount of plastic material so that metal particles that are mixed with the plastic material are exposed. For this it is necessary to design the pre-molded part so that the areas to be activated can be reached by the laser.

Finally, in step S6, the metal layer is applied to the laser-activated areas. This is done by chemical galvankik. 2 B shows a second view of the preform 1 with the applied conductor tracks 3 , Contact points 4 to the EL film and contact points 5 , via which the button can be connected to an external voltage source. The arrangement of the conductor tracks 3 is how out 2 B is not limited to a single level, rather the conductor track runs 3 over two planes of the preform arranged perpendicular to one another 1 ,

The one with the 3-D MID process with conductor tracks 3 and connection contacts 4 . 5 provided pre-molded part is inserted into a second injection mold in step S7 and overmolded in step S8 to achieve the final key shape.

In step S9, the key is removed from the injection mold. Finally, in step S10, a decorative coating is applied to at least one partial surface (first, visible surface area), which later faces an operator and also includes the electroluminescent film. Finally, in step S11, the coating applied to the electroluminescent film is partially removed again, in particular by means of a laser. The coating is partially removed in such a way that the exposed area is a symbol 13 represents. Since the exposed area is arranged directly on the electroluminescent film, it is illuminated when the electroluminescent film is activated, while the light emitted by the EL film is blocked by the coating in the surrounding areas.

2c shows the finished key 6 with the on the first visible surface area 12 applied electroluminescent film 2 , of which only the free area of the symbol 13 is visible. 2d shows a 180 ° rotated view of the button 6 , with the outer contacts 5 are recognizable in the key base. The conductor tracks 3 run in an interior of the button 6 and are not visible to a user.

A predetermined haptic of the key To produce, a subsequent painting of the button and a previous coating of the EL film material possible with soft clear lacquer. A previous coating before the deep drawing and back injection process with soft clear varnish also has the advantage that small tool defects (e.g. marks) on the top of the key.

In 3 a flow diagram of a second method variant is shown. In method steps S101 to S104, a preform is produced by means of film back injection technology analogously to the method steps S1 to S4 described above. However, a readily galvanizable material, such as Bayblend T45, is used as the plastic material. Then, in step S105, by applying a photoresist, all areas of the pre-molded part where no galvanic layer is to be deposited are masked. All non-masked areas, in particular the intended contact points and conductor tracks, are coated with an electroplating layer in step S106. Advantageously, the surface of the button or the pre-molded part facing the user is also kept free of the masking, so that this visible surface area is also galvanized in the same operation, so that the user has a metallic appearance. In this case, however, a sub-area that represents a symbol is masked on the EL film.

In step S107, the partial galvanized pre-molded part inserted in a second injection mold and in step S108 with a plastic material for manufacturing molded the finished button. This second encapsulation can in particular with a different type of plastic material it is in particular an inexpensive material, however, towards the adhesion to the first plastic material pay attention.

4a shows a preform produced by the second method 101 with an EL foil 102 , 4b shows a second view of the preform 101 with the applied conductor tracks 103 and contact points 104 . 105 , 4c shows a 180 ° rotated view of the preform 101 after electroplating, leaving the visible surface area 112 also has a decorative metal layer created by the plating step. The surface area 112 However, it also has an area that is not covered with a metal layer and the symbol 113 represents. The symbol 113 is arranged directly on the EL film so that it can be illuminated. 4d and 4e show the finished key in two different representations, in particular the symbol 113 representing area on a surface area facing the user 112 the button and the contact points 105 are recognizable in the key base. The electrical contact points and the conductor tracks are thus arranged on a surface area which is not visible to the user.

The electrical connection of the button to a printed circuit board takes place during the assembly of an operating device with the aid of spring contacts that are between the contact points 5 . 105 and corresponding contact points of a printed circuit board are arranged.

With the keys according to the invention extremely flat device structures or control panel structures. This is particularly due to the fact that additional Lighting devices, such as light-emitting diodes and light guides, for illumination are not necessary, because the lighting through the thin EL film is realized.

Claims (21)

Illuminated plastic injection molding ( 6 . 106 ) with a display function that shows a first, visible surface area ( 12 . 112 ) with a film and a second surface area, characterized in that the first, visible surface area ( 12 . 112 ) of the plastic injection molded part ( 6 . 106 ) form-fitting with the plastic injection molded part ( 6 . 106 ) connected electroluminescent film ( 2 . 102 ) and directly on the second surface area of the plastic injection molded part ( 6 . 106 ) Conductor tracks ( 3 . 103 ) for the voltage supply of the electroluminescent film ( 2 . 102 ) are applied. Illuminated plastic injection molding according to claim 1, characterized characterized in that it is used as a control unit for a switching device or is designed as a display panel. Illuminated plastic injection molding according to claim 2, characterized characterized in that the second surface area on which the conductor tracks are arranged as an invisible surface of the display panel or Control panel is formed. Illuminated plastic injection molding according to one of the preceding claims, characterized in that the first, visible surface area ( 12 . 112 ) of the plastic injection molded part ( 6 . 106 ) at least partially has a paint job. Illuminated plastic injection molding according to one of the preceding claims, characterized ge indicates that the first visible surface area ( 12 . 112 ) of the plastic injection molded part ( 6 . 106 ) has at least partially a galvanic metal coating. Illuminated plastic injection molded part according to one of the preceding claims, characterized in that the plastic injection molded part ( 6 . 106 ) a symbol ( 13 . 113 ) which, due to a light-tight partial coating of the electroluminescent film ( 2 . 102 ) is limited. Illuminated plastic injection molding according to one of the preceding claims, characterized in that the conductor tracks ( 3 . 103 ) Connection contacts of the electroluminescent film with connection points ( 5 . 105 ) of the plastic injection molded part ( 6 . 106 ) on which the plastic injection molded part ( 6 . 106 ) is electrically connected to a circuit board. Illuminated plastic injection molding according to claim 7, characterized in that the connection of the connection points ( 5 . 105 ) of the plastic injection molded part ( 6 . 106 ) with the circuit board by means of spring elements. Illuminated plastic injection molded part according to one of the preceding Expectations, characterized in that it is a control panel of a switch or Button for Motor vehicles is trained. Process for the production of a plastic injection molded part ( 6 . 106 ) with an electroluminescent film by - injection molding the electroluminescent film ( 2 . 102 ) with a metallizable, thermoplastic material in an injection mold, - applying a metal layer to linear areas of the plastic injection molded part to produce conductor tracks ( 3 . 103 ) to the contacts of the electroluminescent film. A method for producing a plastic injection molded part according to claim 9, characterized in that in the step of back-molding the electroluminescent film ( 2 . 102 ) one with pre-molded part ( 1 . 101 ) is produced and after the build-up of the metal layer, the pre-molded part is extrusion-coated with a further plastic material in a further injection molding tool Method according to one of the preceding claims, characterized in that at least one of the conductor tracks ( 3 . 103 ) is applied so that it runs over at least two inclined surfaces. Method for producing a plastic injection molded part according to one of the preceding claims, characterized in that the electroluminescent film ( 2 . 102 ) is three-dimensionally deformed before the back injection. Process for producing a plastic injection molded part according to any of the preceding claims, characterized in that the metallizable, thermoplastic Plastic material can be laser activated and before the application of the Metal layer first the line-shaped Areas of the plastic injection molded part activated by means of a laser become. Method according to one of the preceding claims, characterized characterized that the metal layer by chemical electroplating is applied. A method according to claim 14 or 15, characterized in that that the applied metal layer is galvanically reinforced. Method according to one of the preceding claims, characterized in that the plastic injection molded part ( 6 . 106 ) is at least partially painted or provided with a PVD coating. A method according to claim 17, characterized in that the electroluminescent film ( 2 . 102 ) is painted and the painting of the electroluminescent film ( 2 . 102 ) to produce a light symbol ( 13 . 113 ) is partially removed again, in particular by means of a laser. Process for producing a plastic injection molded part according to any of the preceding claims 10 to 13, characterized in that to build up the metal layer first a mask and then a metal coating on the non-masked areas is applied. A method according to claim 19, characterized in that by applying the metal coating, both a metallic coating of the linear areas for producing conductor tracks ( 3 . 103 ) and partly a decorative coating of the plastic injection molded part ( 6 . 106 ) he follows. Method according to one of the preceding claims, characterized in that the plastic injection molded part ( 6 . 106 ) is produced as a key cap for a motor vehicle switch or push button.