Patent Abstract:
An operating surface for home appliances having an operating panel with at least one operating element and/or indicator element thereon arranged. The operating panel, at least one operating element and/or the at least one indicator element can be illuminated, at least in part, by at least one electrically operated light source. The light source includes at least one organic electroluminescent component, for example an organic light-emitting diode (OLED).

Full Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to an operating surface for home appliances having an operating panel with at least one operating element and/or indicator element arranged thereon, wherein the operating panel and/or the at least one operating element and/or the at least one indicator element can be illuminated, at least in part, by at least one electrically operated light source.  
         [0003]     2. Discussion of Related Art  
         [0004]     It is known to employ transparent operating surfaces in electrical household appliances, elevators or similar electrical devices. Transparent plastic materials or glass are used as the panel material. The components essential to the operation of the electrical device are arranged at or on the operating surfaces. These are input elements, such as switches, control and regulating units, which are for example embodied as rotary, sliding and toggle switches, as well as proximity switches. Visual indicator elements, such as seven-segment indicators, light-emitting diodes, graphics-capable displays, glow lamps, for example, as well as backlit structured elements printed on the panel, are also employed. Acoustic indicator elements can also be integrated.  
         [0005]     The indicator elements are primarily used for acknowledging a performed input to the user, or to provide information regarding the operational status, for example when running a program. It is also possible to visually show error reports, as well as warning signals.  
         [0006]     The customary design of the operating panels is determined by the shape of the panel, the arrangement and the type of the input and output elements, as well as by printed material. Also, light sources arranged behind the operating panel can take over design functions.  
         [0007]     The indicators with graphic displays used are elaborate in their implementation and expensive to produce, but allow the representation of various types of information in different ways.  
         [0008]     The light-emitting diodes, glow lamps, incandescent lamps or similar standard light sources customarily employed for illuminating structured elements applied to the operating panel have one disadvantage, that they are not flat and thus do not offer a uniform illumination of larger surfaces in particular. The light propagation of standard light-emitting diodes, for example, is directed, so that the brightness of such a light source is largely a function of the observation angle. Also, the standard light sources have a relatively large structural height, which greatly restricts the design possibilities of the operating surface.  
       SUMMARY OF THE INVENTION  
       [0009]     It is one object of this invention to provide an operating surface, in particular for home appliances, which can be uniformly lit, while having a low structural height. Also, the operating surface in accordance with this invention is intended to be inexpensive, and its illuminating device should save energy and provide a large design range.  
         [0010]     The object is achieved with an operating surface, particularly for home appliances, with the characteristics described in this specification and in the claims.  
         [0011]     Accordingly, the light source contains at least one organic electroluminescent component. Such components have a particularly low current consumption at low voltage and can be produced flat in almost any arbitrary shape.  
         [0012]     In one embodiment, the organic electroluminescent component comprises an organic light-emitting diode (OLED). Along with a particularly good adaptability, the OLED can be advantageously produced. It offers novel design options, for example for a night design, with a flat illumination of the operating panel, wherein the total structure of the operating panel and the OLED can be made very flat. This offers advantages with respect to the structural height, in particular in combination with the use of flat proximity switches. Uniform, flat and bright back-lighting of the operating panel is assured by use of the OLEDs. Furthermore, the brightness of flat OLEDs is independent of the observation angle. Large structured elements can be uniformly backlit, and a multitude of colors can be represented.  
         [0013]     In an advantageous manner, the operating panel and/or the operating element and/or the indicator element are constructed, at least partially, of glass, plastic or similar transparent materials. During this, the at least one organic electroluminescent component shines through the respective transparent elements. For this purpose, the at least one organic electroluminescent component can be arranged on the side of the operating panel and/or the operating element and/or the indicator element facing away from the observer and facing toward the device.  
         [0014]     For example, in order to achieve the flat backlighting of partial areas of the operating panel or, for example, a homogeneous representation of indications by the organic electroluminescent component, in the same color and with the same brightness, at least one structured element embodied as a positive or negative representation can be applied to the side facing the user and/or to the side facing away from the user and facing toward the operating panel and/or the operating element and/or the indicator element. In this case the structured elements can include letters, numbers, any arbitrary two-dimensional shapes or similar symbols. The embodiment of frame shapes or flat borders, for example on the operating panel, can be realized as desired with the structured elements. Special design applications, and moreover comfortable user guidance, can be easily realized with the backlit structured elements.  
         [0015]     For this purpose at least one structured element, which is backlit by at least one organic electroluminescent component, can be imprinted on the side of the operating panel and/or the operating element and/or the indicator element facing toward or away from the user.  
         [0016]     To produce an operating surface which is as smooth as possible and insensitive to soiling, at least one structured element in the form of a mask arrangement, which is backlit by at least one organic electroluminescent component, can be applied between the at least one organic electroluminescent component and the side facing away from the operating panel and/or the operating element and/or the indicator element.  
         [0017]     To achieve a visual emphasis of defined symbolic elements, a plurality of structured elements and organic electroluminescent components can be provided. In this case at least one organic electroluminescent component is assigned to each structured element and backlights the associated structured elements and/or a surrounding area defined at the structured element.  
         [0018]     So that the visually emphasized symbolic elements can also display individual information contents, it is possible to provide a plurality of organic electroluminescent components, of which at least individual organic electroluminescent components can be separately controlled. For realizing this individual control, the individual organic electroluminescent components can be connected with each other via a bus.  
         [0019]     Additional information can be displayed if the organic electroluminescent components radiate light in preset colors. However, alternatively the transparent material of the operating panel and/or of the operating element and/or of the indicator element can be colored in a predetermined color, at least near or in the area of the attached structured elements.  
         [0020]     In a particularly advantageous manner, the organic electroluminescent components can be designed flat, angled or curved in accordance with the shape of at least a portion of the operating panel and/or the operating element and/or the indicator element. The organic electroluminescent components can have round, square or similar predetermined arbitrary shapes. Thus it is possible to realize completely individual design applications. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     This invention is explained in greater detail in view of preferred embodiments and making reference to the drawings, wherein:  
         [0022]      FIG. 1  shows a schematic view from above on an embodiment of an operating surface of a household washing machine with backlit operating panel areas and backlit operating and indicator elements;  
         [0023]      FIG. 2  shows a schematic lateral and sectional view of an operating surface of a household washing machine in accordance with one embodiment; and  
         [0024]      FIG. 3  shows a schematic lateral and sectional view of an operating surface of a household washing machine in accordance with another embodiment. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0025]     One embodiment of an operating surface of a household washing machine with an operating panel  10 , which has a backlit operating panel area  11  and operating elements  12  and  14  and a two-digit seven-segment indicator  16 , is shown in a schematic view from above in  FIG. 1 .  
         [0026]     The operating surface is arranged in the front area of the washing machine and has an operating panel  10  made of glass, plastic or similar transparent material, which is backed by an opaque mask. A frame-shaped area  11  is cut out of the mask, on which a flat organic light-emitting diode (OLED) is arranged on the side facing the washing machine. The light radiated by the OLED passes through the transparent operating panel  10  in the frame-shaped area  11 , so that an illuminated frame is formed. The OLED radiates colored light, so that the frame area  11  has a special design meaning by the “night design” here represented. The frame area  11  is uniformly illuminated and can be viewed at the same brightness from any arbitrary visual angle, because the OLED does not radiate the light in a directed way.  
         [0027]     A rotatory input knob  12  for selecting the washing program is arranged on the operating panel  10  in the left area of the operating surface next to the frame  11 . The rotatory input knob  12  has different rotatory positions, which are identified by the letter sequence “A, B, C, D, E, F, G, H” in accordance with the selectable washing programs. Defined segments are assigned to the individual letters on the rotatory input knob  12 . The areas of the segments of the rotatory input knob  12  are of a transparent plastic material, on whose side facing the operating panel  10  the letters “A, B, C, D, E, F. G. H” are applied in the form of a positive mask made of an opaque material, or are printed. In addition, the segments assigned to the individual letters each have an OLED on the side facing the operating panel  10 . Depending on the switch position of the rotatory input knob  12 , an OLED is triggered, or provided with a voltage, so that it radiates and simultaneously indicates the segment provided with the defined letter. In this way the set washing program can be easily read off by the user with the radiating letter segments “A, B, C, D, E, F, G, or H”. In  FIG. 1 , the segment with the letter “B” is represented to be illuminated, by which it is indicated that the B washing program is activated.  
         [0028]     Six keys  14  are arranged in the center area of the operating panel  10 , which are used for selecting additional washing programs, such as “easy care washing cycle”, “rpm reduction” or the like. In the represented embodiment, the six keys are provided in a simplified way by the numbers “1, 2, 3, 4, 5, and 6”. The individual keys  14  are made of a transparent plastic material facing the user, and an OLED is placed behind each one. If one of the keys  14  is pressed, the associated OLED is activated. In  FIG. 1  the key with the number “3” is depressed, so that the corresponding OLED radiates.  
         [0029]     A two-digit seven-segment indicator  16  is arranged to the right of the keys  14  on the operating panel  10 , which have seven individually controllable OLEDs. All numbers between 0 and 99 can be represented by such a display. The indicator  16  shown in the drawing represents the remaining running time of the washing program, in the represented case the number “19”, which indicates that the washing program will be finished in nineteen minutes. Only the radiating OLEDs of the indicator are visible. For this purpose, at least the area of the indicator  16  is made transparent on the operating panel  10  so that, although the radiating OLEDs are visible, the unilluminated OLEDs remain hidden. In this case the OLEDs of the rotatory knob, of the keys, of the “night light” and of the seven-segment indicator can have different colors, or can be white. It is possible to realize a uniform appearance if the OLEDs are laid out in one color.  
         [0030]      FIG. 2  shows in a schematic lateral view and in section an operating surface of a household washing machine. The operating surface has an operating panel  10 . The user views the lateral face  22  of the operating panel  10 , while the illuminating arrangement, for one, and also the front of the washing machine are arranged on the opposite side  20  of the operating panel  10 . A structured mask layer  24 , for example made of a self-adhesive opaque foil, is applied to the side  20  of the operating panel  10 . In place of the mask layer  24 , a structured layer, or the symbols themselves, can be imprinted in a positive or negative representation.  
         [0031]     In its left portion, the mask layer  24  forms a symbol  24 . 1 , for example a letter or a number. In the center and right portions, however, the mask layer  24  is embodied so that flat areas  24 . 2  and  24 . 3 , for example a frame structure, such as the frame structure  11  represented in  FIG. 1 , is left free. An active layer of OLEDs adjoins the mask layer  24 . An OLED  18 . 1  is arranged at the symbol  24 . 1  and radiates through the symbol  24 . 1  and thereafter through the transparent operating panel  10 . Further OLEDs  18 . 2  and  18 . 3 , which are wired together via a bus system and can be individually controlled, are arranged in the flat areas  24 . 2  and  24 . 3  and radiate through them.  
         [0032]     A similar operating surface of a household washing machine is shown in a schematic lateral view and in section in  FIG. 3 . In contrast to the embodiment explained in view of  FIG. 2 , a structured layer  26  is imprinted on the side  22  of the operating panel facing the user. In its left area the structured layer  26  forms a symbol  26 . 1 , for example a letter or a number. In the center and right areas, however, the structured layer  26  is embodied so that flat areas  26 . 2  and  26 . 3 , for example a frame structure, such as the frame structure  11  shown in  FIG. 1 , is left free. The structured layer  26  is imprinted on the transparent operating panel  10 . A passivating, or protective layer made of a transparent lacquer can be applied to the structured layer  26 .  
         [0033]     An active layer of OLEDs adjoins the side of the operating panel  10  facing the device. An OLED  18 . 1  is arranged below the symbol  26 . 1 , which radiates through the transparent operating panel  10  and thereafter through the symbol  26 . 1 . Further OLEDs  18 . 2  and  18 . 3 , which are wired together via a bus system and can be individually controlled, are arranged underneath the flat areas  26 . 2  and  26 . 3  and radiate through them.  
         [0034]     The OLEDs  18 . 1 ,  18 . 2 ,  18 . 3  radiate light of different colors. For example, the symbol  24 . 1  or  26 . 1  is illuminated in yellow by the OLED  18 . 1 , while the flat area  24 . 2  or  26 . 2  is illuminated in green by the OLED  18 . 2 , and the flat area  24 . 3  or  26 . 3  is illuminated in blue by the OLED  18 . 3 . The operating panel  10  can be colorless and transparent.  
         [0035]     It is possible to embody the operating panel  10  to be colored and transparent, and the OLEDs  18 . 1 ,  18 . 2 ,  18 . 3  can radiate neutral light through the operating panel  10 .  
         [0036]     In accordance with the embodiments shown in  FIGS. 2 and 3 , the operating panel  10 , the mask layer  24 , or the structured layer  26 , as well as the associated OLEDs  18 . 1 ,  18 . 2 , and  18 . 3  are flat. However, the operating panel  10  can also be curved, corrugated or angled. The mask layer  24 , or the structured layer  26 , as well as the associated OLEDs  18 . 1 ,  18 . 2 , and  18 . 3 , can follow this shape. The OLEDs can also be embodied in a large range of arbitrary shapes.  
         [0037]     German Patent Reference 103 36 354.8, the priority document corresponding to this invention, and its teachings are incorporated, by reference, into this specification.

Technology Classification (CPC): 3