DE20013019U1 - Electronics control unit - Google Patents

Abstract

The electronic user panel has a main holder (7) that has formed actuator elements (8) positioned near to switches (2). Push button caps (3) fit into a separate key housing (10). The caps are designed to fit into sealing layer (13) that protects against water splashes.

Description

27.07.2000 01889-00 T/hw

Liebherr-Hausgeräte GmbH D-88416 Ochsenhausen

Electronic control unit

The present invention relates to an electronic control unit with an electronic holder for supporting an electronic unit, wherein the electronic holder has at least one actuating element for actuating a switch of the electronic unit, an operating panel for covering the electronic holder, and at least one operating button for operating the at least one actuating element.

Such electronic control units are used in various household appliances, domestic technology or entertainment electronics, in particular they can be used for refrigerators to operate the refrigerator controls. The requirements for such electronic control units are diverse. On the one hand, they are subject to the aesthetic requirements of an attractive device design. On the other hand, various technical functions must be fulfilled. In addition to the clear visual display of the respective stored function of the respective control button, it must be ensured in accordance with the given approval requirements that the control unit as a whole is splash-proof so that the electronic unit is not damaged if a more or less large splash of water is accidentally poured over the control unit during operation. According to the

In addition, the creepage and clearance distances must be complied with in accordance with the approval requirements. Finally, the entire control unit should be cost-effective to manufacture.

Printed soft keyboards are already known that are designed as a switch mat with contact surfaces that bridge corresponding contacts on the electronic board when activated. However, such known soft keyboards are not very appealing in terms of their visual appearance and could be improved in terms of usability. Electronic control units with hard individual keys that are movably mounted between a control panel and the electronic unit are also already known. However, the assembly and cost-effective manufacture of such known control units could be improved. In particular, the required splash-proofness is relatively difficult to achieve.

The present invention is therefore based on the object of creating an improved electronic control unit of the type mentioned, which avoids the disadvantages of the prior art and advantageously develops the latter further. In particular, a visually appealing and yet inexpensively manufactured control unit is to be created, which adequately protects the associated electronic unit from the environment.

According to the invention, this object is achieved by an electronic control unit according to claim 1. Preferred embodiments are the subject of the subclaims.

The at least one control button is therefore attached to the side of the control panel facing the electronics holder and extends through a corresponding button recess in the control panel. A splash-proof seal is connected between the control panel and the at least one control button. The control buttons pass through the control panel from the back to the front, where they are operated. The control panel itself can be adjusted accordingly in the

be essentially flat or with a smooth surface so that an attractive, aesthetic appearance is achieved. From the outside, only the surface of the control panel itself and the operating surface of the respective control buttons are visible. In order to prevent water from penetrating the electronic unit despite the control buttons passing through the control panel, a seal is provided between the control panel and the respective control buttons, which blocks any water accidentally spilled over the control unit right at the control panel.

In a further development of the invention, the seal between the control panel and the at least one control button can have a gap labyrinth that surrounds the at least one or each control button. This catches water that penetrates directly at the control button or buttons, so that it cannot penetrate deeper into the control unit.

In a further development of the invention, a key housing can be provided on which the control keys are movably mounted and which is connected to the control panel in a fluid-tight manner. In a particularly advantageous manner, all control keys can be pre-assembled on the key housing, so that the key housing together with the control keys forms an assembly module. The control keys can in particular be locked onto the key housing. The keyboard pre-assembled in this way can be mounted as a unit on the control panel, which considerably reduces the assembly effort. In addition, the housing protects the sensitive keys during assembly and transport.

A fluid seal is provided between the key housing and the control panel, which surrounds the control keys in a ring or frame shape, in order to prevent water from penetrating through the seam between the key housing and the control panel. In particular, the key housing can be placed on the control panel from behind, i.e. on the side of the control panel facing the electronics holder. The seal between the key housing and the control panel can be achieved, for example, by welding the keyboard housing to the

The control panel can be connected in particular by means of ultrasound or laser. Preferably, the key housing can be glued to the control panel. In particular, the key housing can be glued to the control panel by means of a double-sided adhesive tape which extends in a frame-like manner along the edge of the key housing.

The connection between the key housing and the control panel therefore has a dual function. Firstly, it serves to attach the key housing and thus the control buttons. Secondly, it seals the key housing from the control panel.

The control buttons are preferably sealed from the button housing by means of the aforementioned gap labyrinth.

According to another embodiment of the invention, in which only a single or a few control buttons are provided, the button housing can be dispensed with. The control buttons can be mounted directly in the control panel. The control panel can have corresponding button receptacles on which the control buttons are movably mounted, in particular locked. The seal between the control button(s) and the control panel is achieved by a gap labyrinth directly between the control panel and the control button.

An advantageous embodiment of the invention consists in that all or a group of the control buttons are connected to one another, with elastic connecting elements, in particular spring elements, being provided between the control buttons, so that each control button can be moved relative to its neighboring control buttons and is reset by the respective spring elements. In particular, multi-legged spring angles can be integrally formed between neighboring control buttons, which are in particular U-shaped and are connected by their respective ends to neighboring control buttons. A chain-like connection of the control buttons is therefore provided, with the respective chain links between neighboring control buttons serving as spring and reset elements.

serve. The U-shaped spring pieces are arranged in alternating directions, preferably in such a way that a meandering chain of connections is created between the control buttons. The connection of all control buttons to one another makes assembly much easier, as the control buttons form an assembly. It is impossible to install individual control buttons in the wrong position. In addition, the connection of the control buttons to one another also serves the function of returning the control buttons to their original position after they have been pressed. The spring-like arrangement of the control buttons has particular advantages, particularly in conjunction with the button housing described above. The button housing protects the spring pieces between individual control buttons.

In another advantageous embodiment of the invention, in which only a few control buttons are provided or the control buttons are far apart from each other, the control buttons can be designed as individual buttons. No connections are provided between the control buttons. Each button is attached individually. Preferably, each control button is latched directly onto the control panel so that the button housing can be omitted. In order to avoid confusion between the different control buttons during assembly, the control buttons advantageously each have different codings. The coding preferably consists of a shape coding of a switch plunger of the respective control button.

In an advantageous development of the invention, a lighting device is provided for illuminating the control buttons, which can be arranged in particular on the side of the electronics holder, such that the control button is illuminated. An active optical display is advantageously provided for the operation of the respective stored function of the corresponding control button.

In order to achieve a strong illumination of the respective control button, it is advantageously provided that the lighting device for the respective control button has a lighting means which is located directly on the front side opposite

the control button. In order not to collide with the corresponding switch of the electronic unit, the control button is offset relative to the associated switch of the electronic unit, so that space is created for the respective lighting device. The switch is operated indirectly via the actuating element belonging to the electronic holder. The lighting device can be arranged directly on the electronic unit and form part of it. A light recess can be provided in the electronic holder arranged between the electronic unit and the keyboard, through which the lighting device can extend or shine.

The control button itself or at least a part of it can be designed as a light guide. In particular, a switching plunger of the respective control button forms a transparent light guide. The switching plunger can be made of a suitable plastic for this purpose.

The control buttons are expediently provided with preferably colored symbols that are illuminated by the lighting device and symbolize the corresponding function of the control button to the user of the device. The symbols can be applied in different ways. For example, the buttons can have relief-like depressions. The symbols can also be matte so that the corresponding surface of the control button lights up differently when illuminated. Preferably, however, the symbols are printed on the respective control button, in particular applied using the pad printing process.

In a further development of the invention, the control buttons are made of plastic. In particular, they can be injection-molded.

According to another advantageous embodiment of the invention, the control buttons are formed by a film that has one or more embossings, each of which forms a control button. The non-embossed areas of the film connect the control buttons that are designed as embossings. The film is expediently designed to be elastic so that the control buttons can be pressed individually.

In a further development of the invention, the film with its non-debossed areas is attached to the back of the control panel, i.e. on the side of the control panel facing the electronics holder. The film is preferably attached to the control panel in a fluid-tight manner. In particular, the film can be glued to the control panel. Although the film is arranged on the back of the control panel, easy operation is achieved by the debossed control buttons, which extend through corresponding recesses in the control panel. The debossing is dimensioned in such a way that a sufficient stroke of the respective control button is guaranteed.

If necessary, a separate key cap can be applied to the film as an alternative to or in addition to the embossing of the film. The key cap applied in this way is preferably made of transparent material and is molded onto the film on the user side.

In a further development of the invention, the film is printed in color on its back, i.e. on the side facing away from the user interface, in order to form corresponding function symbols. The back printing on the back prevents the print from wearing off. Areas that are to be translucent later can be left free of printing or printed in a different color. The arrangement of such a control button film is characterized by the symbols being completely abrasion-resistant and, on the other hand, has no continuous openings or gaps from the touch surface to the electronics, which ensures absolute splash-proofness.

In a further development of the invention, an operating plunger is provided between the foil and the electronics holder, which protrudes from the respective actuating element of the electronics holder towards the foil in a dome-like manner and preferably adapts to the contour of the respective embossing in the foil. With the help of such a plunger, the impression of a hard operating keyboard can be avoided despite the use of a membrane keyboard.

ste, while at the same time utilising all the advantages of film technology in terms of surface, colours, translucency and abrasion resistance.

Particularly in conjunction with a backlit button, the actuating plunger can be made of transparent material and designed as a light guide. For this purpose, it can be located in a corresponding recess in the electronics holder, behind which the corresponding lighting means is arranged.

The invention is explained in more detail below using preferred embodiments and associated drawings. In the drawings:

Fig. 1 is a section through an electronic control unit according to a preferred embodiment of the invention, showing several control buttons arranged next to one another, one of which is backlit,

Fig. 2 is a perspective exploded view of the electronic control unit from Fig. 1, wherein a control panel through which the control buttons extend has been omitted,

Fig. 3 is a partial sectional view similar to Fig. 1 of a single button which is mounted directly in the control panel,

Fig. 4 is a rear view of the control button from Fig. 3, showing its coding and arrangement in the control panel,

Fig. 5 is a partial sectional view similar to Fig. 3 of a single key which is backlit,

Fig. 6 Sectional views of various individual control buttons with different codings,

Fig. 7 is a partial sectional view similar to Fig. 1 of an electronic control unit according to a further embodiment of the invention, in which a deeply embossed foil is provided as the control button, and

Fig. 8 is a partial sectional view similar to Fig. 7 of an electronic control unit according to a further preferred embodiment of the invention, in which a deeply embossed foil with a control dome placed thereon is provided as the control button.

Fig. 1 shows the control unit for an electronics system 1, which can be designed as an electronic circuit board and has a plurality of switches 2 arranged next to one another in series. The switches 2 can in particular be known buttons.

According to the number of switches 2, the control unit comprises a plurality of control buttons 3, which can actuate the switch 2 assigned to them when pressed down. The control buttons 3 are part of a keyboard 4, which is arranged in front of the electronic unit 1 and is covered by a control panel 5. As Fig. 1 shows, the control panel 5 completely covers the keyboard 4 on the outside. Only the control buttons 3 protrude through the control panel 5 through corresponding button recesses 6.

The electronic unit 1 is locked onto an electronic holder 7, which is designed as a plastic injection-molded part and is arranged between the circuit board of the electronic unit 1 and the keyboard 4. To actuate the switches 2, the electronic holder 7 has actuating elements 8, which are designed as spring-loaded switching tabs and are integrally formed on the body of the electronic holder 7. As shown in Fig. 2

shows, the switching tabs 8 in the electronics holder 7 are delimited by U-shaped cutouts in the latter, so that the switching tabs 8 each form a self-supporting arm, the base of which is opposite the free end and is connected to the body of the electronics holder 7. The control buttons 3 actuate the switches 2 indirectly via the respective associated switching tabs 8 of the electronics holder 7. This indirect actuation makes it possible to achieve individual tolerance compensation between the control buttons 3 and the switches 2 of the electronics unit 1, which can be designed as short-stroke switches. If the keyboard 4 is used in a curved front housing, the different height from the straight electronics board to the curved front can be compensated for by the switching tabs 8. In the design shown in Fig. 1, the control panel 5 can be curved. The position of the operating side of the control buttons 3 follows the curvature radius of the control panel, the plunger height of the switching tabs 8 is different in each case.

As shown in particular in Fig. 2, the control buttons 3 are connected to one another. Between each adjacent control button, U-shaped spring angles 9 are provided, which are integrally connected to the control buttons 3. The control buttons 3 can be injection-molded together with the spring angles 9 from a suitable plastic. The essentially U-shaped spring elements 9 open transversely to the connecting line of two adjacent control buttons 3, i.e. the two parallel legs of the spring elements 9 extend approximately tangentially to the two associated adjacent control buttons 3. The control buttons 3 form a chain together with the spring elements 9, with the spring elements 9 being arranged alternately with their open side, so that a meandering arrangement of the spring elements 9 results (see Fig. 2).

The control buttons 3 are inserted into a separate button housing 10, which has a corresponding number of button receptacles 11. The control buttons 3 are seated in the button receptacles 11 of the button housing 10 so that they can be pressed down. However, the connection between the control buttons 3 and the button housing 11 is designed to be rotationally and tilt-proof, so that

ti .;

that the operating buttons 3 cannot twist or tilt. The operating buttons 3 pass through the button housing 10 with a central actuating plunger 12 in order to be able to actuate the switching tabs 8 with it.

Between the operating buttons 3 and the button housing 10, a gap labyrinth 13 is provided, which forms a seal between the button housing 10 and the respective operating button 3. As Fig. 1 shows, each operating button 3 has a web 14 arranged coaxially to the central actuating plunger 12 at a radial distance therefrom, which is cylindrical in shape just like the actuating plunger 12. An annular gap is thus formed between the annular web 14 and the central actuating plunger 12, into which the button housing 10 engages with a complementarily shaped projection 15, so that overall a gap labyrinth is formed between the button housing 10 and the operating button 3 (see Fig. 1).

The key housing 10 with the pre-mounted control buttons 3 is placed as a unit from behind on the control panel 5, i.e. the key housing 10 sits on the side of the control panel 5 facing the electronics unit 1. A seal 16 is provided between the control panel 5 and the key housing 10, which seals the seam between the key housing 10 and the control panel 5. In particular, the key housing 10 is glued to the control panel 5 with a double-sided adhesive tape 16. As Fig. 2 shows, the double-sided adhesive tape t6 extends in a frame shape along the edge of the key housing 10 and surrounds the key receptacles 11. The adhesive tape 16 also serves to attach the key housing 10 to the control panel 3 and vice versa.

Due to the connected structure of the control keys 3, they do not need to be specially attached to the key housing 10. The spring elements 9, which are locked between the key housing 10 and the control panel 5, prevent the control keys 3 from slipping out. However, in order to prevent damage to the spring elements 9 and to create a pre-assembled keyboard unit, a spring can be installed between the control keys and the key housing 10.

A locking connection can be provided. For this purpose, the operating buttons 3 can preferably have positive locking projections 17 on their actuating tappets 12 and/or the button receptacles 11 of the button housing 10 (see Fig. 2).

In a further development of the invention, the control buttons or one of the control buttons is backlit. They are illuminated from their rear side, i.e. the side facing the electronics unit 1, so that the surface of the control buttons 3 facing the user is illuminated. A lighting means 19 can be arranged on the electronics unit 1 as the lighting device 18. The electronics holder 7 has a lighting recess 20 at the corresponding point, through which the lighting means 19 can illuminate the respective control button 3. As Fig. 1 shows, the lighting means 19 is advantageously arranged directly opposite the front side of the control button 3, so that the control button 3 can be directly illuminated with light that is just incident on it, whereby a high luminosity can be achieved. For this purpose, the control button 3 is arranged offset relative to the switch 2 assigned to it, which is made possible in particular by the indirect actuation of the switch 2 with the aid of the switch tab 8.

The respective operating button 3 is provided with a function symbol that is applied using the tampoprint process. The actuating plunger 12 of the backlit operating button 3 is manufactured as a transparent light guide using a two-component process. The symbol 21 is shown flush with the touch surface made of transparent plastic. The light guide could alternatively be designed as a separate assembly part that can be snapped on, glued, welded or attached in any other suitable way.

The arrangement shown creates a control keyboard that can be backlit with great luminosity and that also achieves the required splash-proofness. The labyrinth seal between the key housing 10 and the control key 3 creates a

·· ·♦·♦

-13-

sufficiently long sealing section in the button housing. On the other hand, the button housing is tightly connected to the control panel 5.

If only a few control buttons 3 are required or if the control buttons are arranged far apart from one another, the structure of the control unit can be simplified. As the design according to Figs. 3 to 6 shows, the button housing 10 can be omitted and the respective control button 3 can be mounted directly in the control panel 5. The control buttons 3 are designed as individual buttons, i.e. they are not connected to one another via spring elements or the like. The control buttons 3 are, as shown in Figs. 3 and 5, locked into the control panel 5 from the front by means of locking hooks on the actuating plunger 12. The control panel 5 has corresponding button receptacles 22 which guide the respective control button 3 so that it can be pressed down. However, as in the previously described embodiment, the mounting is designed to be non-rotatable and non-tilting. The torsion resistance is achieved here by a non-circular cross section of the actuating plunger 12 and the associated recess in the control panel 5. In particular, the shape of the cross section of the actuating plunger 12 and the associated recess in the control panel 5 can be used to code the control buttons 3 in order to avoid confusion between the different buttons during assembly. The cross sections of the control buttons and the respective associated recesses in the control panel 5 are coordinated with one another in such a way that only one correct control button 3 fits into the associated recess. Various codings are shown in Figs. 4 and 6.

In order to prevent the ingress of splash water, a gap labyrinth 24 is provided between the control panel 5 and the respective control button 3 as a seal 23, which surrounds the control button 3. As in the previously described embodiment, the control button 3 has a cylindrical web 14 that protrudes from the edge of the button coaxially to the central actuating plunger 12 and engages in a complementary annular groove in the control panel 5. In the gap formed between the web 14 and the actuating plunger 12 in the control button 3

-14-

a complementarily shaped projection 25 of the control panel 5 engages (see Fig. 3).

Even when a single button is mounted directly in the control panel 5, if illumination of the control button is desired, it can be arranged offset from the switch 2 of the electronic unit 1, so that the lighting means 19 is located directly opposite the front side of the corresponding control button 3 (see Fig. 5). The switch 2 is indirectly actuated by the switching tab 8, which bridges the offset between the control button 3 and the switch 2.

In order to provide the necessary restoring force when storing individual keys, the switching tabs 8 of the electronics holder 7 can be designed with a pre-tensioning force so that they push the operating keys 3 into their starting position.

As an alternative to the described design of the keyboard with injection-molded control keys made of hard plastic, the keyboard can be implemented using a film 26, as shown in the designs according to Figs. 7 and 8. The control key 3 is formed by a film 26. The dome-shaped or cup-shaped design of the control keys 3 is achieved by embossing the film 26, which is designed in such a way that sufficient travel of the key is guaranteed (see Fig. 7).

Alternatively and/or additionally, a separate dome can be applied to the film 26 by the user (see Fig. 8).

Both the film 26 and the optionally provided separate dome 27 are preferably made of transparent material so that the keyboard can be illuminated. Symbols are expediently printed on the transparent film 26, whereby areas that are to be illuminated later can be left free from printing. The symbols are advantageously printed on the back of the film 26, i.e. on the side facing the electronic unit 1, so that absolute abrasion resistance is achieved.

·&egr;·» »-4 ti

The embossed and optionally printed film is placed on the back of the control panel 5, i.e. on the side facing the electronic unit 1, and secured there. The attachment can basically be carried out in various ways. Preferably, the film 26 is introduced into the control panel 5 from the inside using double-sided adhesive tape, so that the key caps protrude through the corresponding recesses in the control panel (see Fig. 7 and 8).

In order to give the membrane keyboard the subjective impression of a hard keyboard, actuating plungers 28 made of hard material can be provided under the membrane 26, which are spherical and fit into the contour of the foil embossing (see Fig. 7 and 8). The actuating plungers 28 can be used to actuate the switching tabs 8 of the electronics holder 7 and thus the switches 2 of the electronics unit 1 by pressing down the embossed tips of the membrane 26. The actuating plungers 28 are advantageously attached to the switching tabs 8 and protrude from them in the shape of domes towards the membrane 26. In order to be able to backlight the operating keys 3, i.e. the corresponding embossings of the membrane 26, an illumination recess 29 can be provided in the corresponding switching tab 8. The actuating plunger 28 is located therein and is designed as a transparent light guide to guide the corresponding light from the lighting device located behind the electronics holder 7 onto the film 26.

The main advantages of the membrane keyboard are the absolute abrasion resistance of the symbols printed on the back and the complete absence of openings or gaps from the key surface to the electronics. This ensures absolute splash-proofness. In addition, the actuating plungers 28 located under the membrane 26 give the impression of a hard key.

Claims (16)

1. Electronic operating unit with an electronic holder ( 7 ) for supporting an electronic unit ( 1 ), wherein the electronic holder ( 7 ) has at least one actuating element ( 8 ) for actuating a switch ( 2 ) of the electronic unit ( 1 ), a control panel ( 5 ) for covering the electronic holder ( 7 ), at least one control button ( 3 ) for operating the at least one actuating element ( 8 ), wherein the control panel ( 5 ) has at least one button recess ( 6 ), the control button ( 3 ) extends through the button recess ( 6 ) and is fastened on the side of the control panel ( 5 ) facing the electronic holder ( 7 ), and with a splash-proof seal ( 13 , 16 ; 24 , 16 ) which is connected between the control panel ( 5 ) and the control button ( 3 ). is. 2. Electronic control unit according to the preceding claim, wherein a lighting device ( 18 ) for illuminating the control button ( 3 ) is provided, in particular arranged on the side of the electronics holder ( 7 ) in such a way that the control button is illuminated. 3. Electronic control unit according to the preceding claim, wherein the control button ( 3 ) is arranged offset relative to the associated switch ( 2 ) of the electronic unit ( 1 ) and the lighting device ( 18 ) has a lighting means ( 19 ) arranged opposite the front side of the control button. 4. Electronic operating unit according to one of the preceding claims, wherein the operating button ( 3 ) is designed as a light guide, in particular a switching plunger ( 12 ) of the operating button is designed as a transparent light guide made of plastic, wherein preferably an operating-side end of the transparent light guide is designed in the form of a symbol for the stored function. 5. Electronic control unit according to one of the preceding claims, wherein the control button ( 3 ) is provided with a symbol, which is preferably printed thereon. 6. Electronic control unit according to one of the preceding claims, wherein a plurality of actuating buttons ( 3 ) are provided which are connected to one another, wherein elastic connecting elements ( 9 ), in particular spring elements, are provided between the actuating buttons, preferably integrally formed on the actuating buttons ( 3 ). 7. Electronic control unit according to one of the preceding claims, wherein a plurality of control buttons ( 3 ) are provided, each having different codings. 8. Electronic control unit according to one of the preceding claims, wherein the seal has a gap labyrinth ( 13 ; 24 ) which surrounds the at least one or each control button ( 3 ). 9. Electronic control unit according to one of the preceding claims, wherein a key housing ( 10 ) is provided, on which preferably all control keys ( 3 ) are movably mounted, in particular latched, the key housing ( 10 ) is connected to the control panel and a fluid seal ( 16 ) is provided between the key housing and the control panel, enclosing the at least one key recess in the form of a frame. 10. Electronic control unit according to the preceding claim, wherein the button housing ( 10 ) is placed on the side of the control panel ( 5 ) facing the electronics holder ( 7 ) and is preferably glued to the control panel ( 5 ) by means of a double-sided adhesive tape ( 16 ). 11. Electronic control unit according to one of the preceding claims, wherein the control panel ( 5 ) has button recesses ( 22 ) on which the control buttons ( 3 ) are mounted, in particular latched. 12. Electronic control unit according to one of the preceding claims, wherein the at least one or each control button ( 3 ) consists of plastic, in particular is injection-molded. 13. Electronic control unit according to one of the preceding claims, wherein the control buttons ( 3 ) are formed by a film ( 26 ) which has an embossing extending through the button recess ( 6 ), wherein the film is preferably fastened, in particular glued, to the side of the control panel ( 5 ) facing the electronics holder ( 7 ). 14. Electronic operating unit according to the preceding claim, wherein a preferably transparent actuating plunger ( 29 ) is arranged between the film ( 26 ) and the electronics holder ( 7 ), in particular is fastened to the actuating element ( 8 ) of the electronics holder ( 7 ). 15. Electronic control unit according to one of the two preceding claims, wherein the film ( 26 ) is printed in the region of its embossing on its side facing the electronic unit ( 1 ), wherein the printing is preferably partially recessed to allow illumination of the control button. 16. Electronic control unit according to one of the preceding claims, wherein an operating button ( 3 ) is provided which is formed by a film ( 26 ) which has an embossing extending towards the control panel and a preferably transparent dome placed on the embossing.