Abstract:
The invention relates to a user interface device for controlling an electrical consumer, in particular, a light system. Further, it relates to light system using such user interface device. Moreover it relates to a method for controlling such light system using a user interface device. To provide a user interface device, a light system and a method for controlling a consumer load providing feed forward or feed-back information facilitating an easy and intuitive use of the user interface device when controlling a light system, a user interface device for controlling a connected light system ( 44 ) is proposed, comprising: a display unit ( 12 ) including a plurality of LEDs ( 13 ) in a matrix form, wherein each of the LEDs ( 13 ) of the matrix is addressable individually; an input unit ( 11 ) to receive a user input; a control unit ( 40 ) adapted to receive a signal ( 1   a ) based on the user input and to generate an information signal ( 1   b ) provided to the display unit ( 12 ) and to generate a control signal ( 1   c ) for controlling the connected consumer load ( 44 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a user interface device for controlling an electrical consumer, in particular, a light system. Further, it relates to light system using such user interface device. Moreover it relates to a method for controlling such light system using a user interface device. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the fields of controlling electrical consumer loads user interface devices like switches or dimmers are used to adjust an amount of an electrical power provided from an electrical power source to an electrical consumer load. The electrical consumer load might be a lamp in a lighting system including a plurality of different lamps, an electrical motor in a home appliance like a kneading machine or in a vacuum cleaner or an electrical heater. In the easiest case the switch is a hard switch for merely switching on/off the power supply to the electrical consumer load. In an on state, the maximum available electrical power is supplied to the electrical consumer load and in the off state, no electrical power is supplied to the electrical consumer load. User interface devices or soft switches like dimmers can be applied to continuously adjust the electrical power supply to the electrical consumer load. Such dimmers have become popular in controlling light appliances. 
         [0003]    Light systems are one of the most important ambience makers. People use light appliances to create different ambiences for different moods or activities. Research has shown that people also like to use colored light to further enhance those ambiences. Therefore, light appliances include a full color light sources to enable people to create these ambiences. 
         [0004]    Further advanced light appliances are flexible and integrated. Such light systems comprise multiple full color light sources, variable color temperature light sources and ‘normal’ functional light sources. In some cases such light systems further interact with other electrical consumer loads like a HIFI-device, an electrical heater or an air-conditioner to further enhance the ambience generation. In other words, modern light systems do not only comprise a conventional illumination function but also ambience creation functions for influencing the mood in a room. At the beginning, these functions where merely applied in professional environments in offices and shops. However, this kind of ambience creation becomes more and more popular to average users. 
         [0005]    Since these advanced light systems include a plurality of different lamps and in particular multiple full color light sources and/or variable color temperature light sources, the control of such advanced light appliance is very complex. A user interface device for controlling the light system requires a unique switch for each of the ambience creation function. This results not only in a huge space requirement for the overall light controller but makes the user interface device also difficult to use for average users. These discussed disadvantages are also valid for other electrical consumer loads to be controlled by a switch, like a plurality of indoor units of air conditioners in a house. 
         [0006]    WO 2007/072315 proposes to interconnect a user interface and a light source to be electrically controlled by the user interface with an electronic controller. The electronic controller receives an instruction from the user interface and adjusts the electrical power at the light source based on the user instruction. 
         [0007]    However, the application of conventional control devices for controlling an electrical consumer load is getting more complex or unmanageable with an increasing of the complexity of the overall system. This makes it difficult to use conventional control devices especially for the average user. 
         [0008]    With the different possibilities and functions of such light systems, different and new types of controls are required. Next to on/off and dimming, one can envision controls for pre-set selection, color setting, daylight ambience, and so on. However such control functions are quite complex and the user is not aware which setting represents a desired characteristic of the light system. The user can only try several control functions until he arrives at the desired one. However, the feedback via the light system is very inconvenient. 
       OBJECT AND SUMMARY OF THE INVENTION 
       [0009]    It is therefore an object of the present invention to provide a user interface device, a light system and a method for controlling a consumer load providing a feed forward or feedback information facilitating an easy and intuitive use of a user interface device when controlling an electrical consumer load, in particular a light system. 
         [0010]    The object is solved by the features of the independent claims. 
         [0011]    The invention is based on a thought to provide a user interface having a matrix of LEDs and an input unit, wherein when outputting a control signal to the consumer load, in particular a light system, to output in parallel an information signal to the display unit to provide a kind of feed forward or feedback information to the user via the display device. Each LED of the matrix in the display unit is individually addressable. The LEDs are particular full color solid state LEDs, which are capable to display a plurality of brightness values and color values. Further by using the LEDs it is possible to provide symbols or low level text to illustrate control elements for controlling the light system to the user. The user interface device looks similar to a conventional light switch so that the user will easily recognize it as a light controller. It is proposed that the user interface device has various control functions, which are programmable. The input device is preferably realized as a touch sensitive module for receiving a user input to control the setting of the light system. This provides the advantage that the user has the possibility to use a plurality of different control functions by maintaining a good easy-off use of the user interface device. The combination of the user interface device having a display device and an input unit according to the invention gives the possibility to provide the direct relation between the light output by the display device of the user interface device and the light setting in the room. 
         [0012]    The matrix of LEDs is used to provide feed forward or feedback information on the status of the light. First of all, the light of the LEDs can reflect the light provided by the light system, which is controlled. Secondly, the matrix of LEDs is used as low resolution display to render a user interface comparable to a commercial user interface to display control elements like scales, preset area, symbols, text and numbers. This could be achieved since LEDs can be addressed easily and individually, so that the plurality of LEDs within the matrix could be driven differently thereby having the possibility to have a full degree of freedom to amend the colors, the brightness and the illustration of the LEDs on the display device. LEDs are easy to produce and could be driven without much effort. Further they have an acceptable power consumption compared with expensive LCDs. Moreover, they could be controlled to output a light, which could be easily recognized, even if light is incident on the surface of the display unit. Moreover, limitations like viewing angle or refreshing rate are uncritical. 
         [0013]    Preferred embodiments of the invention will be explained based on the dependent claims. 
         [0014]    The LEDs of the display unit output a light having the same characteristic as a characteristic of the light output by the light system. Thus, if the light system is controlled to be maximal in its level also the light output by the display unit is to be controlled to be maximal. The same applies for controlling the level in a dimming function to be minimal. 
         [0015]    Preferably, the user interface device is equipped with a proximity sensor and/or a brightness sensor. Since the providing of feedback or feed forward information on the user interface device is only necessary, if a user is in proximity to the user interface device it is proposed to display the feed forward or feedback information only during controlling the light system or to provide the information only if the user is in a predetermined proximity to the user interface device. Moreover, the intensity of providing the information could be controlled to be dependent on the daylight. Therefore, it is advantageous to have a brightness sensor included in the user interface device to provide a signal as a reference for adjusting the brightness of the provided information. This provides the possibility to increase the recognizability for the user. Moreover, this avoids a waste of energy. 
         [0016]    Preferably, it is proposed to illuminate a small area, which is softly glowing by switching on a group of LEDs of the matrix to indicate that the light system is switched off, wherein the intensity of the light of the glowing area is based on the brightness or depending on a detected person. 
         [0017]    When a user touches the input unit, the small area, which is softly glowing, will be changed in its appearance. It is possible to illuminate the whole area or a larger part of the small area in the same color or in the level, which is output to the light system. Thus, the user may easily recognize that the lights are switched on. This will facilitate the control of the light system if the light system is not directly in proximity of the user interface device, like a hidden place or another room. 
         [0018]    Moreover, by the input unit in front of the display device it is possible to sense a moving direction on the input device to control the setting of the light system continuously. The input unit will detect the moving direction of an object on its surface, wherein depending on the moving direction and on the amount of moving or distance of the movement the control unit will adapt the characteristic of the light system respectively. Thus, when a user moves his finger to the lower edge, the light system will be dimmed to nearly switched off, wherein when moving the finger to the upper edge of the user interface device, the control unit will recognize this movement and will control the connected light system to be dimmed to fully switched on. Moreover, the amount of dimming may be represented by dividing the area of the display unit into parts, wherein the lower parts illuminated for instance in yellow indicates the amount of light outputted by the light system and the upper part is not illuminated and indicates the amount of the remaining amount. 
         [0019]    Moreover, the control unit is equipped with a memory for storing a dimming level output to the light system before switching off the light system. Thus, when switching on the light system, the user interface device is able to use the stored dimming level and to control the connected light system depending on the stored dimming level. 
         [0020]    Preferably the user interface device may output the control signal to the light system in two different ways. One alternative could be to display on the display unit the respective level of the light directly when moving the finger on the touch pad before sending out the respective control signal. The corresponding control signal to control the connected light system based on the user input is output if the finger is released from the input unit. Thus, the user may recognize, what is the effect on its respective user input before setting the respective light system. 
         [0021]    Another alternative is that the control signal output to the light system is sent directly to the light system when touching or moving the finger on the input unit, wherein the display unit in the user interface device may receive in parallel or simultaneously the corresponding information signal to provide the feedback information. 
         [0022]    Preferably, the user interface device may have a cover layer having a certain relief in its surface, so the user interface device may provide feed forward information to the user as to how to use a controller. A flat surface on the cover layer suggests a touch action on preset areas to switch on a preset number of lights of the light system or to switch on or off the light system, while a vertical dent suggests the possibility for up and down movement to dim the level of the light system or to amend the color temperature depending on a colored scale displayed under (i.e. behind) the vertical dent. 
         [0023]    An alternative possibility is to place a printed piece of paper between the input unit and the display device or in front of the display unit and the input device. Thus, the LEDs of the display device may illuminate the printed piece of paper and the printed scale on this piece of paper may be illuminated. Thus, the user can recognize which kind of colors are possible for the setting and the input unit will recognize a movement of a finger of the user for generating the respective control signal to set the light system correspondingly. In this case it is only required to display a light behind the printed scale on the paper. Thus, the amount of control is reduced since the LEDs need not to be displayed in different colors representing the scale of possible values for the setting of the light system. For inserting the piece of paper a slot is provided to place the paper in front of the LEDs. 
         [0024]    Preferably, it is possible to display on the area of the display unit a plurality of preset areas, wherein the user may select a preset area to activate a pre-programmed setting, wherein the preset areas may be represented in a color, which corresponds to the color of the associated light setting. Moreover, it is possible that the color or size of the preset area is changed after selecting a preset area on the display device. Thus, it may be represented more saturated or with a larger size. Thereby, the user may easily recognize which preset area is selected due to its user input. Further, it is possible to use the background area outside the preset areas to display the color of the associated light setting after selecting a certain preset area. 
         [0025]    In a further embodiment it is possible to represent by the LEDs a colored scale, which may be represented as a horizontal or vertical bar or in ring form or in an open ring form, wherein the scale represents adjustable values of a color temperature, brightness, time or saturation of the light system, wherein the surrounding background area may be used to display the characteristic corresponding to values selected on the scale via the user input. Thus, in case of adjusting the color temperature to be cold, the background of the display unit will be displayed in a white or blue color, wherein when moving the finger into direction of the scale for adjusting a more warm color temperature, the background area will be illuminated in a warm yellow or orange color tone. 
         [0026]    Further, it is possible to use the brightness sensor to control the light system and the display device depending on the current daylight including a predetermined number of light sources, a predetermined color or a predetermined brightness. Thus, it is possible to define depending on the time the number, position and color of the light sources of the light system and to change the setting depending on the daylight and time of the day. 
         [0027]    In a further preferred embodiment, it is possible that the control depending on the daylight or time is performed automatically. Thus, the user interface device will represent the feedback information by displaying a feedback indicator on a scale indicating the current setting of the light system, wherein the feedback indicator is automatically moving depending on time or depending on the daylight sensed by the brightness sensor. This automatic control can be interrupted by a user input. Thus, the user may shift the feedback indicator on the scale into a desired direction and will thereby stop the automatic control, wherein by touching a predetermined area outside the scale the automatic control is restarted. 
         [0028]    Moreover, it is possible to use a timer control function in the user interface device, which allows a dynamic light setting, which could be automatic or user controlled. Thus, it is possible to automatically fade out the light over the time. The amount of time may be represented on the display unit by number of dots, which is decreasing during expiration of time, wherein the user may increase the time for fading out by touching a position for increasing the number of dots. Thus, it is possible to recognize by the user how many dots are displayed and the user may recognize how long it will take until the lights are switched off. 
         [0029]    Preferably, the user interface device includes a control unit, which has a central computing unit, a memory, an LED controller and an input interpreter. Further, a light control interface outputs the control signal to the light system for adjusting the power consumption or other parameters of the connected light system. The touch input interpreter detects a touch on the sensitive matrix on the touch pad and provides the position of the user input to the central computing unit, wherein the central computing unit outputs the information signal to the LED controller for providing the respective feedback/feedback information to the LED matrix for illuminating the matrix corresponding to the user input. Moreover, the central computing unit is outputting the control signal to the light control interface for controlling the connected light system. The memory is connected for storing dimming levels, a number of preset settings for predetermined times or preset scenarios. Further, the brightness and proximity sensors are connected to the central control unit. It is possible to arrange the display device and the input device in layered form, which are then covered by a covering layer. Further, it is possible to insert a piece of paper in front of the display device to illuminate for instance a scale on the piece of paper. A further possibility is to arrange the LEDs and touch sensitive elements together in a common layer. Thus, a very flat user interface device could be achieved. The electronics for controlling the display device and the connected light system may be accommodated in the user interface device, but it could also be located remote to the user interface device, wherein the data transmission may be a wired based or wireless link. 
         [0030]    The object is also solved by a light system using a user interface device as described above. 
         [0031]    Moreover, the object is solved by a method for controlling a light system including the steps of: receiving a user input on a touch pad, determining the position of the user input in the touch interpreter, generating a control signal for controlling the connected light system based on the position of the user input and the current control function performed by the user interface device, generating an information signal corresponding to the control signal and outputting the information signal to the display device including a plurality of LEDs. By this the feedback/feedback information is provided to the user simultaneously or before controlling the connected light system. Thus, the user is able to easily recognize the effects and/or status of the light system during or in advance of the control based on the user input. 
         [0032]    The object is also solved by a computer program or a computer program product performing the steps of the method as described above when executed on a computer. Further, it is solved by a data carrier including such computer program for performing the steps of the method as described above when executed on a computer. Finally, it is solved by a computer executing such computer program for performing the steps of the method as described above when executed on a computer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    The invention will be described in greater detail hereinafter, by way of non-limiting examples with reference to the embodiments shown in the drawings. 
           [0034]      FIG. 1  illustrates an exemplary construction of the user interface device according to the present invention. 
           [0035]      FIG. 2  illustrates an alternative embodiment of the user interface device according to the present invention. 
           [0036]      FIG. 3  illustrates a further embodiment for realizing a user interface device according to the present invention. 
           [0037]      FIG. 4  illustrates a construction of a control unit of the user interface device according to the present invention. 
           [0038]      FIG. 5  illustrates a layout of the user interface device indicating the on/off control-function. 
           [0039]      FIG. 6  illustrates the dimming control function. 
           [0040]      FIG. 7  illustrates a user interface device having a relief or a feed forward paper. 
           [0041]      FIG. 8  illustrates a layout representing preset areas. 
           [0042]      FIGS. 9   a  and  9   b  illustrate a layout of the user interface device illustrating a colored scale. 
           [0043]      FIGS. 10   a  and  10   b  illustrate an automatic daylight control function. 
           [0044]      FIG. 11  illustrates a manual day light control. 
           [0045]      FIG. 12  illustrates a color control with feedback/feed forward information. 
           [0046]      FIGS. 13   a  and  13   b  illustrate feedback indicator and a color control. 
           [0047]      FIGS. 14 and 14   b  illustrate a timer control function. 
           [0048]      FIG. 15  illustrates a further embodiment having multiple display units. 
           [0049]      FIG. 16  illustrates a navigation function of the user interface device. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0050]    In  FIG. 1  the mechanical construction of the inventive user interface device  10  is illustrated having three layers. The first layer includes the display device  12  having a plurality of LEDs  13  arranged in matrix form. In front of the display device  12 , there is an input unit  11 , which may be realized as a touch pad having areas for detecting positions of user input. Moreover, a cover layer  14  is arranged in front of the input unit  11  to protect the underlying first and second layers. The cover layer  14  may have a diffusing function to diffuse the light outputted by the LED matrix. 
         [0051]      FIG. 2  illustrates an alternative embodiment of the present invention. To reduce the effort for driving the display device  12 , it is possible to insert a color layer or piece of paper  15  having a printed first and/or second scale. The color layer  15  is semitransparent. The display device  12  is stacked behind the color layer  15  and may display a certain color through the color layer  15 . By arranging the color layer  15  in front of the display device  12 , it is only necessary for the display device to illuminate the scale or a kind of feedback indicator. Thus, the LED controller  47  and the central computing unit  41  have only to illuminate the scale and/or to change the position of the feedback indicator. Moreover, the control device according to  FIG. 2  includes a touch pad  11  and a protection cover  14  for protecting the other layers. 
         [0052]    According to  FIG. 3 , the LED matrix includes a plurality of single full color LEDs  31  and touch sensitive elements  32  integrated into one single common layer  33 . As shown in  FIG. 3 , the touch sensitive elements  32  surround each single LED  31 . However, it is also possible that two or a small group of LEDs  31  is surrounded by one touch sensitive element  32 . Moreover, it is possible to use a kind of grid, wherein the LEDs  31  are arranged in between the crossings of the grid of touch sensitive elements  32 . The LEDs  31  and the touch sensitive elements  32  are accommodated or supported by a rigid surface layer  33  or a flexible surface layer using flex foils. 
         [0053]    With reference to  FIG. 4 , the construction of the control unit  40  in the user interface device according to the present invention will be explained. The user interface device includes a control unit  40  having a central computing unit  41  receiving a user input at the input device  11 , e.g. touch screen, via the user input interpreter  46 . The user input interpreter  46  determines a position of the user input and provides the position to the central computing unit  41 . The central control unit  41  is connected to an LED controller  47  connected to the LED matrix  12 . Moreover, the control unit  41  may be connected to a memory  42  for storing program code, control functions, dimming levels, predetermined colors of a feedback indicator, ect. The central computing unit  41  is connected to a light control interface  43  controlling the connected light system  44 . A brightness sensor  49  and proximity sensor are connected to the central computing unit  41 . 
         [0054]    As described in  FIG. 5 , the user input device is able to switch on/off the connected light system as well as to dim the light system as illustrated in  FIG. 6 . In the left layout of  FIG. 5 , a small soft glow  51  is displayed when the light system is off. Thus, the user can find the user interface device in the dark as well. The light of the small dot  51  is only glowing if the brightness sensor  49  detects that it is somewhat dark or that the daylight is below a predetermined threshold. During normal daylight it is not necessary to indicate the position of the user interface device. Thus, the glowing small dot  51  is not illustrated during daylight. In case of actuating or pressing the surface of the user interface device to switch on the connected light system, the display device of the user interface device will light up to provide the feedback information that the light is switched on. Also in this case, the light up of the display unit is only necessary if the surrounding light is somewhat dark, since during daylight it is neither recognizable nor necessary to indicate on the display device that the light is switched on. If the user presses the input unit  11  at any position again, the light switches off again and the display device again shows a small soft glow. 
         [0055]      FIG. 6  illustrates the use of the user interface device as a dimmer. In a left figure, the situation is illustrated when the light system is switched off. A small dot or area  51  is glowing indicating that the light system is switched off. The user can dim the light by pressing the input unit and moving the finger up and down on the input unit. The position of the finger reflects the light level of the light system, wherein moving the finger completely to the bottom of the input unit completely dims the light system while moving the finger completely to the top of the user interface device sets the light system to the maximum output as shown in the right hand layout of  FIG. 6 . By moving the finger illustrated by the arrow down to the lower edge of the surface of the user interface device, the connected light system is switched off. The display device of the user interface device is then illustrated in white or no color to indicate that no light is switched on. When moving up the finger in vertical direction on the surface of the user interface device as illustrated in the second figure of  FIG. 6 , the lower part of the surface will be illuminated in yellow or other color to indicate that the connected light system is dimmed to 20%, wherein the remaining upper part of the surface is illuminated in white or switched off. Thus, the user is provided with feedback information, that only a small amount of light is output by the light system. When moving the finger to ¾ as shown in the third layout of  FIG. 6 , the light is controlled to be dimmed to 75%, wherein the part illuminated in yellow is increasing and the part on the surface illuminated in white or being switched off is decreasing. Thus, the user may easily recognize that the light is illuminated stronger. The right hand layout in  FIG. 6  illustrates the situation that the connected light system is fully switched on. Then the whole area of the display device is illuminated in yellow. For switching the connected light system in such state, it is necessary to move the finger or object to the upper edge of the surface of the user interface device. When the user switches off the light system by pressing the input unit at a predetermined position the dimming level is stored in the memory  42  of the control unit  40 . If the user presses the input unit  11  again to switch on the light system, this dimming level is used and the light system is set based on the stored dimming level. However, of again moving the finger on the input unit the light system is dimmed, since in this case the position of the finger is determined as the dimming level. 
         [0056]    Note that one can choose an implementation such that when the user presses the user interface device it uses the LED matrix to show what the light level will be, and when the user releases his finger it sends the control signal  1   c  to the light system  44 . In this way the user would look at the display device  12  for feed forward information. This would be useful for dimming or color control as explained later, but it would not be so useful for on/off switching. Therefore, an alternative implementation is that when the user presses the input unit it uses the LED matrix to show what the light level will be and it sends the control signal  1   c  to the light system immediately. In this way the user would look at the lights in the room for feedback information. 
         [0057]      FIG. 7  illustrates examples for providing feed forward information to the user as how to use the user interface device. A left hand layout provides a smooth diffuse cover  71  for diffusing the light of the LEDs  13 , wherein no preferred relief is present. Thus, the user may touch or press at any position of the user input in the left layout. The middle layout of  FIG. 7  illustrates a relief  72  in form of a vertical dent indicating to the user where to move the finger for adjusting an associated value. In the right hand layout of  FIG. 7  the user interface device is equipped with a slot  75  for inserting a paper  74  having a printed scale  73 . The paper  74  is placed in front of the LED matrix  12 . Thus, the LED matrix  12  will illuminate the paper  74  at the area of the scale  73 . Then, the user may move his finger on the scale  73 , thereby controlling the light system  44  depending on the values of the scale. Such realization is easier since the LED matrix  12  needs only to illuminate the scale  73  without being controlled in different colors. 
         [0058]    A further preferred embodiment is illustrated in  FIG. 8  describing a preset selection. The user interface device shows a number of preset areas  81 - 84  that can be pressed by means of multiple dots of glowing light. These preset areas  81 - 84  or dots could be of one color, but alternatively colors could be used which pose some resemblance to the color of the preset. For example a red dot may indicate the cozy, romantic setting of the light system  44 , whereas a blue dot represents a cool, calm, refreshing morning setting. The user can press on a dot  81 - 84  to select the preset. The light color can reflect the (average) light color in the preset. The dot of light of the preset area that is selected is larger than the other dots of light. Again one can choose to provide feed forward information using the lights in the display unit  12 . If the user presses the input unit  11  the preset area  81 - 84  that is not yet lit shows an indication of what the preset will be. As long as the user keeps his finger on the input unit  11  and moves to other preset area, the according light color is shown on the display unit  12 . Only if the user releases his finger the actual preset is selected. Alternatively, a preset is selected and rendered in the room as soon as the user moves his finger onto the preset area  81 - 84  of light representing that preset. The input unit  11  maybe covered by a cover (not illustrated). The cover may have a relief to provide feed forward information to the user as to how to use the user interface device. Multiple small dents suggest multiple preset areas  81 - 84  that can be pressed or selected. This feed forward information can also/additionally be given by using a printed piece of paper. On this piece of paper the preset areas can be indicated with names, numbers or again colors which pose some resemblance to the color of the presets. 
         [0059]    Based on  FIGS. 9   a  and  9   b  a color temperature control is explained. The user interface device illustrates a scale  90  displayed in different colors starting e.g. from yellow at the bottom and blue at the top of the scale. When moving the finger as indicated by the arrows, the background area  91  may be displayed in a color corresponding to the color of the scale. Thus, the user may easily recognize in which color the light system  44  is set. The right hand layout of the  FIG. 9   b  illustrates the situation when the finger is placed on top of the scale  90 . Then, the background area  91  is displayed in blue. 
         [0060]    A third control function, which may be controlled by use of scale  90  as shown in  FIGS. 9   a  and  9   b  is the variable color temperature control for a light system  44  that can render light ranging from cold bluish light to warm reddish light. The display unit  12  shows a scale of light ranging from cold colored light to warm colored light or vice versa. A dot of light within the scale  90  may indicate what light setting is currently selected. The user can press to select a color temperature directly or press and move to change the color temperature. This scale can be vertical or horizontal. Alternatively it can be the whole surface that changes from cold to warm in vertical or horizontal direction. Finally, it can also be a circle. Also for this control function one can choose to provide feed forward information using the LEDs in the user interface device. If the user presses the input unit  11  the area that is not yet lit shows an indication of what the color temperature will be. As long as the user keeps his finger on the input unit  11  and moves for instance left and right, the according light color is shown on the display unit  12 . Only if the user releases his finger the actual preset is selected. Alternatively, the color temperature selected is rendered by the light system immediately. The user interface device may have a relief to provide feed forward information to the user as to how to use it, wherein a linear vertical dent suggests the possibility for up and down movement to vary the color temperature. A linear horizontal dent suggests the possibility for left and right movement to vary the color temperature. A circular dent suggests the possibility to change the color temperature in a circular motion. This feed forward information can also/additionally be given by using a printed piece of paper. 
         [0061]    Based on  FIGS. 10   a  and  10   b  a daylight control function will be explained, the display unit  12  may display an open ring scale  112 , wherein a feedback indicator  113  is displayed within the ring  112  indicating the current preset with the preset value, which is output to the light system  44 . Also here, the background area  91  is used for displaying a light corresponding to the characteristic of the light system  44 . When the feedback indicator  113  is placed in the red values of the scale  112  the background area  91  is illustrated in red (left and right hand layout in  FIG. 10   a ). When the feedback indicator  113  is placed in the blue area of the scale  112 , the background area  91  is illustrated in blue (middle layout in  FIG. 10   a ). 
         [0062]    Daylight control is an essentially variable color control, but it can also comprise the application of different light sources in a system for different settings. For instance, evening light is warm and cozy and hence light near the ground will be used more, while morning light is energizing and bright and hence light near the ceiling will be used. Also, light levels are part of the different settings. For instance evening light is warm and cozy and hence light will be mostly dimmed, while morning light is energizing and bright and hence light will be mostly set to high light levels. Additionally, the user interface device can automatically follow the daylight rhythm by taking into account the time of day. As shown in  FIG. 10   a  and  10   b  the display unit shows a line or partial circle of light showing the various daylight settings. A feedback indicator  113  of light shows what light setting is currently selected. The user can press to select a daylight setting directly or press and move to change the daylight setting. If the user interface device would automatically follow the daylight rhythm, the user would over ride this dynamic. In that case the user would need an option to reset the user interface device to ‘automatic’. For this purpose predetermined area  111  shown as a dot of light at the bottom of the partial circle would offer the option to reset the user interface device to automatic. As already explained for the above-mentioned control functions the background area  91  may be used to provide feed forward information. If the user presses the input unit  11  the background area  91  that is not yet lit shows an indication of what the daylight setting will be. As long as the user keeps his finger on the input unit  11  and moves, the according daylight setting is shown on the display unit  12 . Only if the user releases his finger the actual preset is selected and the control signal  1   c  is output by the control unit  40 . Alternatively, the daylight setting selected is rendered by the light system immediately. A relief may provide feed forward information to the user as to how to use it. A circular dent suggests the possibility to change the daylight setting in a circular motion, and a small dent suggests a button-like action to reset to automatic. Alternatively this feed forward information can also/additionally be given by using a printed piece of paper. 
         [0063]    With reference to  FIG. 11 , a daylight control manual mode with feed forward and feedback information is illustrated. When touching the scale  112  during daylight control, the automatic control is stopped and the light system is switched into a state, which corresponds to the position on the scale, where the finger is pressed as indicated with the arrows. When pressing the finger in the red area of the scale  112  as indicated in the left hand layout the connected light system is switched into a warm color temperature, wherein also the background area  91  is illustrated in a warm red color. Wherein when placing the finger in the blue area of the scale  112  the connected light system and the background area  91  is illustrated in blue as indicated in the middle layout. When pressing the predetermined area  111  at the lower edge of the display unit  12 , the automatic daylight control is activated again. 
         [0064]    With reference to  FIG. 12 , the color control with feedback/feed forward information is explained. When moving the finger as indicated by the arrow on the scale  112  of the display unit the background area  91  is illustrated in the same color as chosen on the scale  112 . Thus, when placing the finger in the blue area of the scale  112  (left hand layout, the background area  91  is illuminated in blue, wherein when placing the finger in the green area  112  (2 nd  left layout) the background area  91  is illustrated in green, wherein when placing the finger in the orange or yellow area of the scale  112  (3 rd  layout) the background area  91  is illuminated in orange, wherein when placing the finger in the red area of the scale  112  (4 th  layout) the background  91  is illuminated in red. 
         [0065]    With reference to  FIGS. 13   a  and  13   b , the color control using a feedback indicator  113  is explained. It is further possible to use a feedback indicator  113 , which is displayed in the scale  112 , wherein the position of the feedback indicator  113  represents the current setting of the light system, wherein the color of the light system is also illustrated via the color of the background area  91 . Thus, when placing the feedback indicator  113  in the blue area, the background area  91  will be illustrated in the white or blue color tone and correspondingly for the other colors as shown in  FIG. 13   b.    
         [0066]    When using full color light sources in a light system color control is an eminent necessity. The users can set the color, but also the color intensity (saturation). It is suggested that the user interface device shows a color circle using the matrix LEDs, as indicated in  FIGS. 10-13 . A dot of light may show what color is currently selected. The user can press to select a color directly or press and move to change the color. Alternatively to a circle a line of colored light can be used to control the light color similar to the dimming and color temperature control. The saturation can be controlled using a line of light ranging from saturated color to white light. This saturated color changes with the color selected. A dot of light shows what saturation level is currently selected. 
         [0067]    Again one can choose to provide feed forward information using the lights in the user interface device. If the user presses the input unit the area that is not lit yet (e.g. background area) shows an indication of what the color and saturation will be. As long as the user keeps his finger on the controller and moves, the according color and saturation is shown on the controller. Only if the user releases his finger the actual setting is realized. Alternatively, the color and saturation selected is rendered by the light system immediately. 
         [0068]    With reference to  FIGS. 14   a  and  14   b  a further control function is explained, wherein the display device illustrates a plurality of small glowing dots  142 - 145  arranged in a circle, wherein the number of dots indicates the amount of time for fading out of the lights of the light system.  FIG. 14   b  illustrates different numbers of dots, wherein the left hand layout indicates maximum number of dots and the right hand layout illustrates the situation shortly before fading out the light. When pressing the finger outside the number of dots as indicated in  FIG. 14   a , the user may increase the number of dots, wherein during expiration of the time the number of dots is decreasing. Thus, the user may easily recognize when the lights will be switched off. Advanced light systems allow for dynamic light settings, either automatic or user controlled. An example of a simple dynamic control is a slow fade out of the light over time, as a more gradual way of switching the lights off. In some cases for instance in a bed room or hotel room the user would want to set the time it takes to switch off the lights so that he can go to sleep. For this it is proposed that the display device shows soft glowing dots  142 -  145  of light in a circle representing 60 minutes for a full circle. If the user presses the input unit of the user interface device at any place, the dots light up brighter. The user can press anywhere on the circle to set the amount of minutes it should take. After this the dots switch off one by one reflecting the time that has passed. The user can always reset the timer to a new time. If the user has set the timer a dot of light in the middle (not illustrated) may provide the option to switch off the timer again. Alternatively a simple clock face with a hand could be displayed and the segments before and after the hand could be of a different color to help reaffirm how much time remains before the lights switch off. By “dragging” the clock&#39;s hand with a finger the user can increase or decrease the amount of time on the timer. Also in this case the cover may be provided with a relief to provide feed forward information to the user as to how to use the timer function of the user interface device. A circular dent suggests the possibility to set the timer and a small dent suggests a button-like action to switch off the timer. This feed forward information can also/additionally be given by using a printed piece of paper. 
         [0069]    Moreover,  FIG. 15  illustrates an embodiment having a plurality of display units with attached input units for controlling connected light system. In this case, it is possible to have one control unit handling the plurality of display and input units, wherein it is also possible to have a control unit per display and input unit. As shown in  FIG. 15 , it is possible to have one user interface device having switch on/switch off function indicated by the small glowing area  151  in the middle, wherein the right hand user interface devices is used for color control, wherein the colored scale  152  is used for changing the color of the light system and the background area  153  is used for providing feedback information to the user, which color is set at the light system. 
         [0070]    As described above with the plurality of different control functions the user interface device can facilitate multiple control functions. In some cases it makes sense to have multiple user interface devices with different control functions ( FIG. 15 ). For instance, an on/off &amp; dimming control and a timer or color control. In other cases it makes more sense to incorporate multiple functions in one user interface device. With multiple functions in one user interface device one could offer these control functions all at the same time, but given the limited surface area of the display unit it is more likely that these functions need to be presented one at a time. This implies the need for navigation from one control function to another. It is proposed to provide a small dot  162 ,  163  of light at the left and right hand side of the display unit to navigate from one control function to another. As illustrated in  FIG. 16 , the navigation from one control function to another control function is explained. Here it is shown on two different control layouts. When offering a plurality of different control functions a navigation indicator  162 ,  163  is displayed. In the left hand layout the normal on/off switching control function having the small glowing area  161  in the middle is illustrated, wherein when pressing the navigation indicator  162  the control function illustrating the colored scale  164  is illustrated on the display device. Pressing the navigation indicator  163  the color control function is switched back to on/off function. By navigating through the different control function, it is possible to control the connected light system in different characteristics, wherein it is easily possible to understand the different control functions by using the illustrated scales and the provided feed forward and feedback information of corresponding to the settings of the connected light system. 
         [0071]    The invention can be applied for any light or light system. It is however especially useful for lights or light systems with extended control possibilities, like color control, timers, daylight control, et cetera. These light systems are becoming available in professional domains like the retail domain, but also in consumer domain, like hotel rooms, homes and gardens.