EP0981144A1 - Control key with integrated illumination and method of making of said key - Google Patents

Abstract

The illuminated button push (1) has an electroluminsecent layer (10) inside the upper push button surface. When the push button is pressed down, a circuit (31,41) is closed lighting the button.

Description

The invention relates to a control key as found therein. especially in keyboards, such as mobile phones, and more particularly a control button with integrated lighting comprising a support and control part in relief, supporting at least one indication character, and means for lighting the indication character. In the case of a keyboard, it is of course necessary to consider a plurality of keys and not just one of them.

For the production of a key, the support part can be molded translucent, apply a layer of semi-transparent paint and a opaque layer of paint and finally reveal the indication character for example by laser engraving.

You can also mold the support part by bi-injection of a material intended to constitute the body of the fingerboard and another material intended for bring up the indication character.

It is also possible to stamp a transparent thermoplastic film on which, at using opaque ink and semi-transparent ink, we screen-print the indication character.

To illuminate the indication character, diodes are most often used electroluminescent (LED) which have the disadvantage of consuming a lot of electrical energy and, therefore, decrease the autonomy of the mobile phone battery, to use this example again.

To solve this problem, we can use a lighting layer electrolumiscent. By EP 847 066, there is a control key, the type defined above, comprising an electrolumiscent lighting layer. However, this electroluminescent layer, supported by a substrate away from the support and control part, provides insufficient lighting.

By DE 26 13 902, there is also known a switch comprising a button and, inside of it, a lighting layer light emitting whose two electrodes are connected to a circuit power supply via a spring and a lug connection. Thanks to the arrangement of the layer, the lighting is more efficient, but the electrical connectors supplying the layer are bulky.

The present invention proposes to provide lighting for a touch of controls, using an electroluminescent layer, efficiently and space-saving.

To this end, the invention relates to a control button with integrated lighting. comprising a support and control part in relief, supporting the less an indication character, and means for illuminating the character indication comprising an electroluminescent lighting layer, characterized by the fact that the lighting layer extends into the bottom of the support and control part and is extended laterally either by electrical contacts, either by electrical connection tracks.

The lighting layer, because it extends into the bottom of the part support, is arranged in the immediate vicinity of the indication character which severely limits lighting losses. In addition, the side extensions of the lighting layer, by electrical contacts or by tracks conductive, provide electrical power to the lighting layer, without increasing the size of the button.

The invention also relates to a method for manufacturing a key such than the one defined above, in which we take a film on which we serigraphy at least one indication character and the said film is stamped to form the support and control part in relief, characterized by the fact we have inside the stamped part a layer of lighting electroluminescent.

In a particular embodiment, before stamping, the lighting layer on an area of said film, intended to form the bottom of the stamped part, and the lighting layer is extended laterally by electrical conductors.

In another embodiment, we take another film on which we deposits the lighting layer which is extended laterally by electrical conductors, a portion of film is cut from said other film supporting the lighting layer with an extension supporting the electrical conductors, and said portion of film is brought back inside the pressed part.

Thanks to this, there is no risk of damaging the lighting layer during stamping.

• la figure 1 représente une vue en coupe latérale de la touche selon une première forme de réalisation;
• la figure 2 représente une vue en coupe latérale d'une couche d'éclairage de la touche de la figure 1;
• la figure 3 représente une vue en coupe et en perpective éclatée d'une partie d'appui et de commande de la touche de la figure 1;
• la figure 4 représente une vue en coupe et en perspective éclatée d'une partie d'appui et de commande de la touche, selon une deuxième forme de réalisation;
• la figure 5 représente une vue en coupe latérale de la partie d'appui et de commande de la touche de la figure 4;
• la figure 6 représente une vue en coupe et en perspective éclatée d'une partie d'appui et de commande de la touche selon une troisième forme de réalisation et
• la figure 7 représente une vue en coupe latérale de la partie d'appui et de commande de la touche de la figure 6.

The invention will be better understood with the aid of the following description of different embodiments of the key of the invention and of various corresponding embodiments of the method of manufacturing this key, with reference to the appended drawing in which:

• Figure 1 shows a side sectional view of the key according to a first embodiment;
• 2 shows a side sectional view of an illumination layer of the key of Figure 1;
• Figure 3 shows an exploded sectional and perspective view of a support and control part of the button of Figure 1;
• FIG. 4 represents an exploded sectional and perspective view of a support and control part of the button, according to a second embodiment;
• 5 shows a side sectional view of the support and control part of the button of Figure 4;
• FIG. 6 represents an exploded sectional and perspective view of a support and control part of the button according to a third embodiment, and
• FIG. 7 represents a side sectional view of the support and control part of the key in FIG. 6.

The control key 50, shown in FIG. 1, belongs to a mobile telephone keypad having a plurality of other keys analogues. For the sake of clarity, only the key 50 will now be described.

The key 50 comprises a support and control part 1, in relief, separated from a substrate 30.

The support and control part 1 consists of a part stamped in a transparent thermoplastic film 20, extending on one side 33 of the substrate 30, in a plane generally parallel to the substrate 30, at a determined distance of it. The control support part 1 has an open recess 3 on the side of the substrate 30 and a bottom 2. An indicative character, in this case a number, is screen printed on the bottom 2, inside the recess 3, in ink semi-transparent, here white, with an opaque ink background, here black.

The recess 3 contains an actuating element 4, integral with the part support and control 1, provided with a support finger 5 projecting out of the recess 3 and intended to cooperate with a contact dome 41, or actuation, elastically deformable.

The support and control part 1 is generally mobile perpendicular to the plane in which the substrate 30 extends, between a rest position and a control position, explained below.

The substrate 30 is a thermoplastic film supporting tracks conductive, not shown, and, on side 33, another thermoplastic film 40 in which the contact dome 41 is stamped.

Two electrical contacts 42, 31, facing each other, are supported by the inner face of the dome 41 and by the substrate 30, respectively. The contact 41 consists of a conductive contact pad and contact 31 includes two portions of conductive contact track connected to tracks conductive of the substrate 30 but not interconnected.

In the rest position, the support finger 5 is in contact with the top of the dome 41 and the two electrical contacts 42, 31 are spaced from one another. In order to dial the screen-printed number on key 50, a user of the mobile phone must press on the support and control part 1, using a finger, moving it from its rest position to its position of ordered. In the control position, the support finger 5 pushes in and deforms the dome 41, by its free end, and the two electrical contacts 42, 31 come into contact with each other. The contact pad 42 then connects between them the two track portions of contact 31, which generates a signal electric control to dial the number printed on the key 40. After removal of the user's finger, the support part 1 and the dome of contact 41 return to the rest position, by elastic return.

• une couche inférieure 6 d'encre conductrice transparente, en l'espèce en ITO (Indium Tin Oxyde), s'étendant sur le film 20,
• une couche diélectrique 7,
• une couche phosphorescente 8 d'encre au phosphore et
• une couche supérieure conductrice 9, ici en carbone.

The bottom 2 supports an electroluminescent lighting layer 10, disposed inside the support and control part 1. This lighting layer 10 successively comprises:

• a lower layer 6 of transparent conductive ink, in this case ITO (Indium Tin Oxide), extending over the film 20,
• a dielectric layer 7,
• a phosphorescent layer 8 of phosphorus ink and
• an upper conductive layer 9, here made of carbon.

The thicknesses of the successive layers 6, 7, 8, 9 are here substantially equal to ten, twenty, thirty and twenty micrometers, respectively. A diaper sealing 11, in transparent varnish, covers the lighting layer 10.

The lighting layer 10 therefore comprises two conductive layers 6, 9 in look at each other and separated from each other by the dielectric layer 7 and the phosphorescent layer 8. These two conductive layers 6, 9 make capacitor armature and each extend laterally by a conductive track 13, 12 for connection to an electrical supply, not shown, extending from the bottom 2 on the inner side walls of the support and control part 1 and, outside this part 1, at back of the film 20. The “back” of the film 20 designates the side of this film which is not visible at the user, disposed on the side of the substrate 30.

In operation, when armatures 6 and 9 are supplied electrically, they create an electric field between them, as in a capacitor. Under the action of this field, the phosphorescent layer 8 emits light that illuminates the screen-printed indication character on the button 50.

After the structural description of the control key 50, its method of manufacture will now be described.

We take a transparent thermoplastic film 20. On the back of the film 20, we imprint the indication character in semi-transparent ink white, on an area intended to constitute the background 2, and a background, in ink opaque black.

On the back of the film 20, on the area intended to constitute the inner face of the background 2, an ink deposition is carried out successively, by screen printing transparent conductive, a deposit of a dielectric substance, a deposit phosphorus ink, carbon deposit and varnish deposit sealing, in order to deposit the electroluminescent lighting layer 10 with its waterproof coating 11. When depositing the lighting layer 10, the frames 6 and 9 are made to extend laterally (the ink deposit conductive and carbon deposition), beyond the area intended to form the bottom 2, - in order to extend the lighting layer 10 laterally by means of electrical conductors, the conductive tracks 13 and 12, which are connected electrically to the power supply.

The film 20 is then stamped to give it the shape of the support part. and control 1, so that the lighting layer 10 extends over the bottom 2 of the stamped part 1. It will be emphasized that, during stamping, we folds the conductive tracks 12, 13, but not the lighting layer 10.

After the forming of the support part 1, a material is injected into it translucent thermoplastic to form the actuating element 4.

We take a film 40, in polycarbonate, on which we place a pellet conductive ink constituting the electrical contact 42. Then the film 40 to form the contact dome 41.

We take a film 30, in polycarbonate, on which we screen-print tracks conductive and the electrical contact 31, using a conductive ink.

Film 40 is stretched against film 30 and these two films are joined together by bonding, by positioning the electrical contacts 31, 42 facing one of the other.

Finally, the film 20 is fixed to the assembly of the two films 30, 40, by positioning the stamped part 1 in line with the dome 41 and interposing between the film 20 and the set of two films 30, 40 of sticky pads, not shown, forming spacers, intended to hold the support and control part 1 away from substrate 30.

A second embodiment of the control key, shown in Figures 4 and 5, differs from the above description only by what will now be described. For the sake of clarity, the elements of this second embodiment bear the references of the corresponding elements of the first embodiment described above, incremented by one hundred.

The control key comprises a support and control part 101, in relief, separated from a substrate.

The support and control part 101, stamped in a film transparent thermoplastic 120, supports an indicative character and contains an actuator 104.

A portion of thermoplastic film 114, of substantially equal dimensions to those of the bottom 102 of the support and control part 101, and supporting, on one side, an electroluminescent lighting layer 110, is added to inside the support and control part 101, in the immediate vicinity of the bottom 102. The lighting layer 110 is turned towards the bottom 102. A film strip 115 laterally extends the portion of film 114 and supports conductive tracks 112, 113 for connection to an electrical supply, themselves laterally extending the lighting layer 110. This film strip 115 extends from the bottom 102 against the side walls inside of the support part 101 and, outside this part 101, against the back of the film 120.

The method of manufacturing the key described above will now be explicit. For the sake of clarity, only the steps in this second mode of realization of the manufacturing process different from those of the first mode of described embodiment will now be explained.

We take a transparent thermoplastic film 120 on which we print, by silkscreen, the indication character in semi-transparent ink and a background in opaque ink.

We take another thermoplastic film on which we deposit the layer 110, on one side, by screen printing. We do laterally extend the reinforcements of the lighting layer 110, in order to extend laterally by electrical conductors, the connecting tracks 112, 113, which are connected to the power supply.

In this other film, the portion of film 114 supporting the layer is cut out. lighting 110, substantially to the dimensions of the bottom 102 of the part support 101, with an extension, the film strip 115, supporting the conductive tracks 112, 113.

After cutting, the portion of film 114 is placed, with its extension 115, against the back of the film 120, placing the lighting layer 110 against an area intended to form the inner face of the bottom 102. Then we stamp simultaneously the film 120 and the portion of film 114 with its extension 115 in order to form the support and control part 101. When stamping, the conductive tracks 112, 113 are folded (but not the layer 110) and the lighting layer 110 is reported inside the stamped part 101, against bottom 102.

A third embodiment of the key does not differ from the first embodiment described only by what will now be described. Through for the sake of clarity, the elements of this third embodiment bear the references of the corresponding elements of the first formed of achievement, incremented by two hundred.

The control key comprises a support and control part 201, in relief, separated from a substrate.

The support and control part 201, stamped in a film transparent thermoplastic 220, supports an indicative character and contains an actuator 204.

An electroluminescent lighting layer 210 is disposed inside of the support and control part 201, on the bottom 202 thereof.

Two electrical contacts 212, 213 extend the layer laterally 210. These two electrical contacts 212, 213 consist respectively in a deposit of conductive ink and in a deposit of carbon. Each contact 212, 213 laterally extends one of the reinforcements of the lighting layer 210, and extends over an area of the interior side wall of the support and control part 201.

A contact recovery film 214, for connection to an electrical supply, is attached to the back of the film 220 (on the substrate side). This film 214 includes strips of film 217, supporting conductive tracks 215, 216 of contact recovery, with two contact recovery tabs 218, 219 each supporting the terminal part of a conductive track 215, 216. The tabs 218, 219 are folded and extend, partly free end, against the inner side wall of the support and control part 201, the end portions of the contact recovery tracks 215, 216 being in electrical contact with electrical contacts 212, 213, respectively.

Instead of connecting the two contacts to the power supply, we could also consider connecting only one of the two contacts to the power supply and put the other contact to ground.

The method of manufacturing the control key described above will now be described. For clarity, only the steps in this third embodiment of the manufacturing process which differ from the first mode of embodiment described will now be explained.

We take a transparent thermoplastic support film 220 on which we prints, by screen printing, the indication character in semi-transparent ink and a background in opaque ink.

On the back of the film 220, on an area intended to form the inside face of the bottom 202 of the support and control part 201, the layer is deposited 210 lighting by screen printing. We reinforce the reinforcements laterally of this lighting layer 210 in order to extend it laterally by electrical conductors, electrical contacts 212, 213.

We take another thermoplastic film on which we print the tracks contact recovery conductors 215, 216. In this other film, we cut the bands 217 supporting the conductive tracks 215, 216 and the two tabs 218, 219 supporting the end portions of the conductive tracks 215, 216, in order to manufacture the contact recovery film 214.

The contact recovery film 214 is placed against the back of the film 220, in turning the conductive tracks 215, 216 towards the film 220 and putting in contact the free end parts of the contact recovery tabs 218, 219 with the electrical contacts 212, 213. Then we stamp simultaneously the contact recovery film 214 and the film 220 in order to form the part support 201, by folding the tabs 218, 219, but not the lighting layer 210. Finally, the contact recovery tracks 215, 216 are connected to the power supply. electric.

To make the lighting layer, instead of depositing the layer first dielectric and then the phosphorescent layer, we could first deposit the phosphorescent layer then the dielectric layer, in order to reverse the order of these two layers.

Claims (11)

Control button with integrated lighting comprising a support part and control (1; 101; 201; 301) in relief, supporting at least one character of indication, and means of lighting the character of indication comprising an electroluminescent lighting layer (10; 110; 210; 310), characterized by the fact that the lighting layer (10; 110; 210; 310) extends in the bottom of the support and control part (1; 101; 201; 301) and is extended laterally either by electrical contacts (212, 213), or by tracks electrical connection (12, 13; 112,113; 312,313). The button of claim 1, wherein the lighting layer electroluminescent (10) comprises two conductive layers (6, 9) forming reinforcements, facing each other and separated from each other by a dielectric layer (7) and a phosphorescent layer (8). Key according to either of Claims 1 and 2, in which the bottom (2; 102) of the support and control part (1; 101) supports the layer lighting (10; 110). Key according to one of claims 1 to 3, in which a portion of film (114), attached to the inside of the support and control part (101), supports the lighting layer (110). A method of manufacturing a key according to claim 1, wherein we take a film (20; 120; 220) on which we screen print at least one indicative character and the said film (20; 120; 220) is stamped to form the support and control part (1; 101; 201) in relief, characterized by the fact that one has inside the stamped part (1; 101; 201) a layer electroluminescent lighting (10; 110; 210). The method of claim 5, wherein, before stamping, depositing the lighting layer (10; 210) on an area of said film (20; 220), intended to form the bottom (2; 202) of the stamped part (1; 201), and laterally extends the lighting layer (10; 210) with conductors electrical (12, 13; 212, 213). Method according to claim 5, in which another film is taken on which the lighting layer (110) is deposited which is extended laterally by electrical conductors (112, 113), said other film is cut a portion of film (114) supporting the lighting layer with a extension (115) supporting the electrical conductors (112, 113), and relates said portion of film (114) to the interior of the stamped part (101). The method of claim 7, wherein said portion of film (114), supporting the lighting layer (110), against an area of said film (120), intended to form the bottom of the support and control part (101), and stamping said film (120) and said film portion (114) to form the support and control part (101). Method according to one of claims 5 to 8, in which it is extended laterally the lighting layer (210) by electrical contacts (212, 213) and a contact repnse film (214) is fabricated supporting tracks contact recovery conductors (215, 216) which are brought into contact with the electrical contacts (212, 213). Method according to one of claims 5 to 8, in which it is extended laterally the lighting layer (10; 110) by connecting tracks electric (12,13; 112, 113). Method according to one of Claims 5 to 9, in which, to form the lighting layer (10), two conductive layers (6, 9) are deposited and, between these two layers (6, 9), a dielectric layer (7) and a layer electroluminescent (8), causing the layers to extend laterally conductive (6,9) to form electrical conductors (12.13).

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