WO2008053425A2

WO2008053425A2 - Interactive luminous drawing board system

Info

Publication number: WO2008053425A2
Application number: PCT/IB2007/054391
Authority: WO
Inventors: Peter T. S. K. Tsang
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2006-11-03
Filing date: 2007-10-30
Publication date: 2008-05-08
Also published as: WO2008053425A3

Abstract

An interactive light-emitting board (2) comprising a plurality of individually controllable light sources (4a-c, 5a-c) arranged on the board, and a control unit (21) for controlling said light sources (4a-c, 5a-c), wherein each light source (4a-c, 5a-c) is switchable between a sensing state (S) and a light-emitting state (LE). The control unit (21) is configured to control at least one of the light sources (4a-c, 5a-c) to the sensing state (S) so as to receive control signals from the at least one light source (4a-c, 5a-c) corresponding to light emitted by a user-controllable light-emitting device (3) and sensed by the at least one light source (4a-c, 5a-c), the light being indicative of requested emission property data, and switch the at least one light source (4a-c, 5a-c) to the light-emitting state (LE) and control the at least one light source (4a-c, 5a-c) to emit light in response to the control signals, thereby forming a luminous pattern on the board (2) corresponding to a position of the user-controllable light- emitting device (3) and to the requested emission property data.

Description

Interactive luminous drawing board system

FIELD OF THE INVENTION

The present invention relates to an interactive light-emitting board, a user- controllable light-emitting device for enabling a user to produce a pattern on such a board, and an interactive luminous drawing board system comprising such a board and user- controllable light-emitting device.

BACKGROUND OF THE INVENTION

Conventional interactive light-emitting boards for, for example, writing or drawing typically include a phosphorous layer which lights up for a while after having been illuminated. Such a board can be locally activated by a light pen, and an area of the board corresponding to the pattern drawn by the light pen emits light until the phosphorous layer has been de-energized. Consequently, the user is substantially unable to control the duration of the drawn pattern.

JP 2004-86488 discloses another interactive light-emitting board and accompanying light pen which allow emission of a drawn pattern in a selected color. The board is formed by a matrix of light-emitting device/photo-detector pairs which are connected to a control unit, and the pen has a color sensor for selecting a pen color and an LED-laser for transmitting signals to the board. When a pattern is drawn, a color is first selected by holding the color sensor adjacent to a model object or color chart. Subsequently, the color information obtained through the color sensor is converted to a digital 30-bit code representing RGB-values. This 30-bit code is then transmitted while drawing the desired pattern on the board. Following the detection of a 30-bit code representing a certain color by a detector, the control unit controls the corresponding light source to emit light of the requested color. The permitted drawing speed is limited by the signaling frequency of the light pen, the processing speed of the board control unit and the resolution of the board (the detector/light source spacing).

The luminous drawing board system disclosed in JP 2004-86488 has the drawback that the construction employing one detector for each light source is not cost- efficient, especially not for a large board or a board having a high resolution. Furthermore, the signaling scheme may lead to either an unacceptably low drawing speed or an undesirably high power consumption of the pen in particular, which is typically battery-powered.

In order to alleviate these and other drawbacks, there is thus a need for an improved and/or more cost-efficient interactive luminous drawing board system.

OBJECTS OF THE INVENTION

In view of the above-mentioned and other drawbacks of the prior art, a general object of the present invention is to provide an improved interactive luminous drawing board system. A further object of the present invention is to achieve a more cost-efficient luminous drawing board system.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, these and other objects are achieved by an interactive light-emitting board comprising a plurality of individually controllable light sources arranged on the board, and a control unit for controlling the light sources. Each light source is switchable between a sensing state and a light-emitting state, and the control unit is configured to control at least one of the light sources to the sensing state so as to receive control signals from the at least one light source, the control signals corresponding to light emitted by a user-controllable light-emitting device and sensed by the at least one light source, the light being indicative of requested emission property data, and to switch the at least one light source to the light-emitting state and control the at least one light source to emit light in response to the control signals, thereby forming a luminous pattern on the board corresponding to a position of the user-controllable light-emitting device and to the requested emission property data.

In its sensing state, the light source is capable of sensing light incident on the light source, and in its light-emitting state, the light source is capable of emitting light. It should be noted that the light source may or may not emit light when it is in its light-emitting state, as controlled by the control unit. In the context of the present application, "emission property data" are understood to be data which are indicative of properties, such as intensity, color, frequency, etc. of light to be emitted by the interactive light-emitting board in response to signals received from a user-controllable light-emitting device, such as a light pen or a light eraser used to draw on or wipe the board. The present invention is based on the recognition that an interactive light- emitting board can be equipped with light sources which are switchable between a sensing state and a light-emitting state, and that these light sources can be controlled so as to first receive control signals from a user-controllable device, such as a light pen, and subsequently be controlled selectively so as to emit light corresponding to the received control signals. The interactive light-emitting board according to the present invention can thus be made with a higher resolution and/or at less cost than prior-art boards having a photo detector arranged together with each light source.

Furthermore, the precision is improved, since the particular device which receives the control signals/light from the light pen used to draw on the board is also capable of emitting light.

The control unit may further be configured to switch the at least one light source back from the light-emitting state to the sensing state so as to allow sensing of light which is indicative of new requested emission property data. This switching back to the sensing state allows control of the light source to emit light corresponding to new control signals, in the form of light from a user-controlled light-emitting device, such as a light pen, which are indicative of new emission property data requested by the user.

Furthermore, erasing of the board is enabled. Upon erasing, a "light eraser" may be swept over the interactive light-emitting board in a manner similar to erasing a conventional whiteboard or blackboard. This "light eraser" may continuously emit light which is indicative of constant emission property data. This emitted light, which may be provided, for example, in the form of a pulse train or a constant DC-type signal, is sensed by the light sources which are being swept over by the light eraser while they are in their sensing state, and subsequently all of these light sources are controlled to emit light (or not to emit light) in accordance with the emission property data. Typically, this emission property data may indicate that all light sources which have been swept over should be dark or that they should be controlled in such a way that the board appears uniformly white (or in any other color). Advantageously, the at least one light source may be kept in its sensing state for a sufficiently short time so as to enable the luminous pattern emitted by the interactive light-emitting board to appear constant to a user when no light indicative of new requested emission property data has been sensed by the at least one light source. In order for the interactive light-emitting board to be responsive to a user, all of the light sources may preferably be switched back and forth between their sensing and light-emitting states. This means that light sources which are emitting light in accordance with previously received emission property data will be switched from time to time to their sensing state, in which they do not emit light but appear dark. In order to prevent the board from flickering, the sensing periods should be made sufficiently short so that the human eye is not able to react to the switching, but perceives the light sources as sources which constantly emit light of the desired properties.

Alternatively, the same effect may be obtained by switching between the sensing and light-emitting states so that a minimum switching frequency is above the perception threshold of the human eye, i.e. about 50 Hz (such as is the case for an ordinary, AC-powered light bulb).

Moreover, the light from the user-controllable light-emitting device may be pulsed, and the requested emission property data may be represented by a frequency of pulses received from the user-controlled light-emitting device.

The control signals may be received from the user-controllable light-emitting device as analog light signals or as digital pulses, the latter being favorable from a noise sensitivity point of view.

In one embodiment of the interactive light-emitting board according to the present invention, the light sources may be grouped in light-source clusters, each cluster comprising at least two differently colored mono-color light sources, whereby a color emitted by each cluster is controllable by controlling the differently colored mono-color light sources.

Although light of a variety of colors, including white, is obtainable from light- source clusters comprising two mono-color light sources, such light-source clusters advantageously comprise three or more differently colored mono-color light sources in order to define a reasonably sized color gamut. Typically, a light-source cluster will include red, blue and green mono-color light sources. However, additional colors, such as amber or cyan may be added to improve the color-rendering capability of the light-source cluster.

The requested emission property data may include at least one of color settings and intensity settings.

Furthermore, recently received emission property data may be superimposed on previously received emission property data, such that a resulting color emitted by a particular light source/light-source cluster corresponds to a mixture of previously and recently requested colors. For example, the crossing point between two differently colored crossed lines drawn on the interactive light-emitting board can be made to emit light having a color corresponding to the addition of the two drawn colors. Alternatively, the color of the first or the second line may be allowed to dominate, in order to, for example, illustrate different layers in a sketch or drawing.

The light sources comprised in the interactive light-emitting board may advantageously be light-emitting diodes, such as semiconductor-based LEDs or OLEDs.

According to a second aspect of the present invention, the above-mentioned and other objects are achieved by a user-controllable light-emitting device for providing light indicative of requested emission property data to an interactive light-emitting board, the user- controllable light-emitting device comprising user input means, a controllable light source, and a control unit for controlling the light source so as to emit the light indicative of requested emission property data in response to signals from the user input means, wherein the user input means comprise a color selector enabling a user to select one of a predetermined set of colors to be drawn on the interactive light-emitting board.

The color selector may be implemented in the form of an actuator, such as, for example, a selector button or a selector wheel. When the color selector is maneuvered by the user, different predetermined color candidates are suitably displayed to the user, such that he may select a desired color among the limited number of available colors. By limiting the available colors to a relatively small number, such as 32 or less, the user is given plenty of choice while the amount of information which has to be transmitted to the interactive light-emitting board is very much limited as compared to the prior-art full-color scheme. Since a considerably smaller amount of data needs to be transferred for each pixel of the board (for example, 5 instead of 30 bits), the drawing speed and/or resolution can be increased correspondingly at a given transmission speed.

Alternatively, the transmission speed can be reduced, leading to a prolonged battery life of the user-controllable light-emitting device. Furthermore, simpler circuitry may be employed to realize the control unit in the user-controllable light-emitting device, which leads to a lower cost. Additionally, the light source comprised in the user-controllable light-emitting device may be controllable to emit pulses of light, and the requested emission property data may be represented by a frequency of the pulses. Moreover, the user input means comprised in the user-controllable light- emitting device may further comprise an intensity input device for enabling the user to set an intensity of a pattern to be drawn on the interactive light-emitting board.

The requested intensity of the light to be emitted by selected light sources in the interactive light-emitting board is transmitted to the selected light sources comprised in the emission property data together with the requested color. In order to additionally transmit the intensity information, a number of additional bits may be used, or the number of selectable colors may be reduced while the number of bits available for transmission of information is being kept constant. The intensity input device may be a pressure-sensitive device configured to output signals which are indicative of a pressure exerted by the user.

In this manner, the user can easily select the intensity of the drawn pattern while drawing the pattern, simply by adjusting the pressure exerted on the pressure-sensitive intensity input device. Furthermore, the controllable light source may be a multi-color light source, and, additionally, the control unit may be configured to control the light source to emit control pulses in a color corresponding to the user-selected color.

It will be readily and intuitively apparent to the user which color is currently selected. Furthermore, since light sources, such as LEDs are typically considerably more sensitive to radiation of the same wavelength than the light source is designed to emit, tuning the color of the light emitted by the user-controllable light-emitting device to the color to be drawn often results in an improved transmission of at least the primary color in the color mix to be emitted by the interactive light-emitting board.

Optionally, the user-controllable light-emitting device according to the present invention may further comprise a beam-spreading device which is arrangeable to spatially spread the light emitted by the controllable light source so as to enable the user-controllable light-emitting device to address a larger portion of the light-emitting board.

Such a beam-spreading device may be present in the user-controllable light- emitting device, and be positioned and adapted so that it can be arranged to spread the light emitted by the controllable light source due to, for example, user actuation of an actuator, such as a button or lever on the pen. The beam-spreading device is then preferably positioned in front of the controllable light source following user actuation. Alternatively, the beam- spreading device may be provided as a snap-on device which can be attached in front of the controllable light source. The provision of such a beam-spreading device enables the user to activate a kind of "brush" function so that a wider line can be drawn on the interactive light-emitting board. The beam- spreading device may allow step-wise or continuous adjustment of the drawn line width. Moreover, the interactive light-emitting board and the user-controllable light- emitting device according to the present invention may advantageously be comprised in an interactive luminous drawing board system.

Additionally, the above-mentioned and other objects of the present invention are achieved by a computer program module adapted to run on a control unit in an interactive light-emitting board according to the present invention so as to cause the control unit to control at least one of the light sources to the sensing state so as to receive control signals from the at least one light source, the control signals corresponding to light emitted by a user- controllable light-emitting device and sensed by the at least one light source, the light being indicative of requested emission property data; and switch the at least one light source to the light-emitting state and control the at least one light source to emit light in response to the control signals, thereby forming a luminous pattern on the board corresponding to a position of the user-controllable light-emitting device and to the requested emission property data.

BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects of the invention will now be described in more detail, with reference to the appended drawings showing a currently preferred embodiment of the invention, wherein:

Fig. 1 schematically shows a preferred embodiment of an interactive luminous drawing board system according to the present invention, comprising an interactive light- emitting drawing board and a user-controllable light-emitting device;

Fig. 2a is a schematic exterior view of the user-controllable light-emitting device shown in Fig. 1;

Fig. 2b is a block diagram schematically illustrating the functional parts of the user-controllable light-emitting device shown in Fig. 2a; and Fig. 3 is a block diagram schematically illustrating the functional parts of the interactive light-emitting drawing board shown in Fig. 1 ;

Fig. 4 is a timing diagram schematically illustrating the operation of the interactive luminous drawing board system shown in Fig. 1. DESCRIPTION OF EMBODIMENTS

The invention will be described with reference to an interactive luminous drawing board system comprising an interactive light-emitting board having a plurality of light-source clusters, each comprising a red (R) LED, a green (G) LED, and a blue (B) LED. It should be noted that this by no means limits the scope of the invention, which is equally applicable to interactive light-emitting boards that are able to display a single color as well as to such boards comprising a plurality of singular multi-color light sources, such as multicolor LED modules.

Fig. 1 shows an interactive luminous drawing board system 1 according to a preferred embodiment of the invention, the drawing board system 1 comprising an interactive light-emitting board 2 and a user-controllable light-emitting device, here in the form of a light pen 3. The interactive light-emitting board 2 is formed by a plurality of light sources 4, 5 (for the sake of clarity, only two of these light sources have been assigned reference numerals) which are mounted on a supporting backboard 6. When drawing with the light pen 3 on the board 2, signals emitted by the light pen 3 are sensed by the light sources 4, 5, which are subsequently controlled to emit light corresponding to signals from the light pen 3, as will be described in more detail below.

Fig. 2a is a schematic exterior view of the light pen 3 shown in Fig. 1, which comprises a color selector 10, a window 11 for display of the selected color, a pressure- sensitive intensity- setting device in the form of a button 12 and a transparent tip 13 for enabling light from an internal light source to exit from the light pen 3.

The function of the light pen 3 illustrated in Fig. 2a will now be described with reference to the schematic block diagram shown in Fig. 2b.

As illustrated in Fig. 2b, a controllable light source 14 is controlled by a control unit 15, which is configured to receive input signals from user input means, here provided in the form of the color selector 10 and the pressure-sensitive intensity- setting device 12.

In Fig. 3, the function of the interactive light-emitting board 2 is illustrated by means of a schematic block diagram, in which the selected light-source clusters 4, 5, comprising mono-color light sources 4a-c and 5a-c, respectively, are connected to a light- source interface 20. The light-source interface 20, which may include well-known components such as shift registers, multiplexers, demultiplexers, sample-and-hold amplifiers, A/D converters and D/A converters, is in turn connected to a control unit in the form of a microprocessor 21, which is also connected to a storage device 22 such as a RAM. When the user draws on the board 2 with the light pen 3, light emitted by the light source 14 comprised in the light pen 3 will exit this light pen 3 through the transparent tip 13 and will be incident on the light sources 4a-c which are included in the drawn pattern as is schematically illustrated in Fig. 3. The emitted light carries requested emission property data in accordance with user settings which have been input to the light pen 3 through control unit 15, color selector 10 and intensity-setting device 12.

When the light sources 4a-c on which the light from the light pen 3 is incident have been switched to their sensing state by the control unit 21 of the light-emitting board 2, the light emitted from the light pen 3 is sensed by the light sources 4a-c and the signals emitted by the light sources 4a-c in response to the sensed light are received via the light- source interface 20 by the control unit 21, which stores the requested emission parameter data for the respective light sources 4a-c in the memory 22. After subsequently switching the light sources 4a-c to their light-emitting state, the control unit 21 controls the light sources 4a-c so as to emit light corresponding to the received requested emission property data stored in the memory 22.

A control sequence for controlling the light sources 4a-c to sense signals from the light pen 3 indicative of requested emission parameter data and to emit light in response to this emission parameter data will now be described with reference to the schematic timing diagrams A-D shown in Fig. 4.

In Fig. 4, diagram A shows the output over time of the light source 14 in the light pen 3, and diagrams B to D show the outputs over time of light sources 4a-c comprised in a selected light-source cluster in response to the control signals received from the light pen 3. As indicated by the letters LE and S, all light sources 4a-c are concurrently switched by the control unit 21 between their light-emitting state and their sensing state, respectively.

Referring to diagram A, the light pen 3 emits a pulse train which is indicative of the color "Red" when passing over the light-source cluster 4. The time when the signal emitted by the light pen 3 can first be received by the light-source cluster 4 is indicated by ti in diagram A. At the time t_ls the light sources 4a-c comprised in the light-source cluster 4 are in their sensing state S and can sense the pulses emitted by the light pen 3. The signals emitted by the light sources 4a-c in response to these pulses are received by the control unit 21 via the light-source interface 20. The signal is decoded in the control unit, for example, by determining the time between consecutive pulses, and the corresponding requested emission property data is stored in the memory 22. After the predetermined sensing period of time ts has elapsed, the control unit 21 switches the light sources 4a-c to their light-emitting state and controls them to emit light in accordance with the requested emission property data stored in the memory 22. Since the requested emission property is the color "Red" in the present case, the red light source 4a is controlled to emit light during the subsequent light-emitting period of time tLE, as illustrated in diagram B, while the green and blue light sources 4b-c are controlled not to emit light, as illustrated in diagrams C and D.

As time passes without any new requested emission property data being received from the light pen 3, the red light source 4a continues to emit light while in its light- emitting state, whereas the green and blue light sources 4b-c remain dark. However, all of the light sources 4a-c are periodically switched to their sensing state so as to allow reception of signals which are indicative of new requested emission parameters from the light pen 3.

At the time t₂, the light pen 3 again passes over the light-source cluster 4, this time emitting light which is indicative of the color "Green". As is evident from Figs. 4a-d, the drawing speed is limited because the light sources 4a-c must be in a sensing state while signals from the light pen 3 can be sensed by the light sources 4a-c. As can be seen in Fig. 4, the light sources 4a-c are switched to their sensing state shortly after t₂. When they are in their sensing state S, the light sources 4a-c sense the pulses from the light pen 3, and the signals emitted by the light sources 4a-c in response to these pulses are received by the control unit 21 via the light-source interface 20 as described above.

In the present example, the board 2 is set to a color mixing mode, in which the color of a crossing point between two differently colored lines is the sum of the two colors. This is illustrated in diagrams B and C of Fig. 4 by the red and green light sources 4a and b, respectively, emitting light at the same time. The blue light source 4c remains dark.

At the time t3, the board 2 is wiped and the light sources 4a-c sense and are subsequently controlled in accordance with a wiping signal.

It will be evident to a person skilled in the art that the present invention is by no means limited to the preferred embodiments. For example, the pressure-sensitive intensity-setting device can be implemented in various other ways, for example, in the form of a pressure-sensitive tip of the light pen. Moreover, the light sources comprised in the light- emitting board may continuously be in their sensing state until the first time they sense control signals, and as a response to these signals are switched to their light-emitting state. Additionally, the light from the user-controllable light-emitting device does not need to be provided in the form of a pulse train having a frequency which is indicative of requested emission property data, but may be provided, for example, in the form of digital signals preferably having a start-of-message indicator preceding the part of the signal which carries the requested emission property data. Furthermore, the light from the user-controllable light- emitting device may be an analog signal.

Claims

CLAIMS:

1. An interactive light-emitting board (2) comprising: a plurality of individually controllable light sources (4a-c, 5a-c) arranged on said board; and a control unit (21) for controlling said light sources (4a-c, 5a-c), characterized in that each light source (4a-c, 5a-c) is switchable between a sensing state (S) and a light-emitting state (LE), and said control unit (21) is configured to control at least one of said light sources (4a-c, 5a-c) to said sensing state (S) so as to receive control signals from said at least one light source (4a-c, 5a-c), said control signals corresponding to light emitted by a user-controllable light-emitting device (3) and sensed by said at least one light source (4a-c, 5a-c), said light being indicative of requested emission property data; and switch said at least one light source (4a-c, 5a-c) to said light-emitting state (LE) and control said at least one light source (4a-c, 5a-c) to emit light in response to said control signals, thereby forming a luminous pattern on said board (2) corresponding to a position of said user-controllable light-emitting device (3) and to said requested emission property data.

2. An interactive light-emitting board (2) according to claim 1, wherein said control unit (21) is further configured to switch said at least one light source (4a-c, 5a-c) back from said light-emitting state (LE) to said sensing state (S) so as to allow sensing of light which is indicative of new requested emission property data.

3. An interactive light-emitting board (2) according to claim 2, wherein said at least one light source (4a-c, 5a-c) is kept in said sensing state (S) for a sufficiently short time (ts) so as to enable said luminous pattern to appear constant to a user when no light indicative of new requested emission property data has been sensed by said at least one light source (4a-c, 5a-c).

4. An interactive light-emitting board (2) according to any one of the preceding claims, wherein said light from the user-controllable light-emitting device (3) is pulsed, and said requested emission property data is represented by a frequency of pulses received from the user-controlled light-emitting device (3).

5. An interactive light-emitting board (2) according to any one of the preceding claims, wherein said light sources (4a-c, 5a-c) are grouped in light-source clusters (4, 5), each cluster comprising at least two differently colored mono-color light sources, whereby a color emitted by each cluster is controllable by controlling said differently colored mono-color light sources (4a-c, 5a-c).

6. An interactive light-emitting board (2) according to any one of the preceding claims, wherein said requested emission property data includes at least one of color settings and intensity settings.

7. An interactive light-emitting board (2) according to claim 6, wherein recently received emission property data is superimposed on previously received emission property data, such that a resulting color emitted by a particular light source/light-source cluster corresponds to a mixture of previously and recently requested colors.

8. An interactive light-emitting board (2) according to any one of the preceding claims, wherein said light sources (4a-c, 5a-c) are light-emitting diodes.

9. A user-controllable light-emitting device (3) for providing light indicative of requested emission property data to an interactive light-emitting board (2), said user- controllable light-emitting device (3) comprising: user input means (10, 12); a controllable light source (14); and a control unit (15) for controlling said light source (14) so as to emit said light indicative of requested emission property data in response to signals from said user input means (10, 12), characterized in that said user input means (10, 12) comprise a color selector (10) enabling a user to select one of a predetermined set of colors to be drawn on said interactive light-emitting board (2).

10. A user-controllable light-emitting device (3) according to claim 9, wherein said light source (14) is controllable to emit pulses of light, and said requested emission property data is represented by a frequency of said pulses.

11. A user-controllable light-emitting device (3) according to claim 9 or 10, wherein said user input means (10, 12) further comprise an intensity input device (12) for enabling the user to set an intensity of a pattern to be drawn on said interactive light-emitting board (2).

12. A user-controllable light-emitting device (3) according to claim 11, wherein said intensity input device (12) is a pressure-sensitive device configured to output signals which are indicative of a pressure exerted by the user.

13. A user-controllable light-emitting device (3) according to any one of claims 9 to 12, wherein said controllable light source (14) is a multi-color light source.

14. A user-controllable light-emitting device (3) according to claim 13, wherein said control unit (15) is configured to control said light source (14) to emit control pulses in a color corresponding to said user-selected color.

15. A user-controllable light-emitting device (3) according to any one of claims 9 to 14, further comprising a beam-spreading device which is arrangeable to spatially spread the light emitted by said controllable light source (14) so as to enable the user-controllable light-emitting device (3) to address a larger portion of said light-emitting board (2).

16. An interactive luminous drawing board system (1) comprising: an interactive light-emitting board (2) according to claim 1 ; and a user-controllable light-emitting device (3) according to claim 9.

17. A computer program module adapted to run on a control unit (21) in an interactive light-emitting board (2) according to claim 1 so as to cause the control unit (21) to control at least one of said light sources (4a-c, 5a-c) to said sensing state (S) so as to receive control signals from said at least one light source (4a-c, 5a-c), said control signals corresponding to light emitted by a user-controllable light-emitting device (3) and sensed by said at least one light source (4a-c, 5a-c), said light being indicative of requested emission property data; and switch said at least one light source (4a-c, 5a-c) to said light-emitting state (LE) and control said at least one light source (4a-c, 5a-c) to emit light in response to said control signals, thereby forming a luminous pattern on said board (2) corresponding to a position of said user-controllable light-emitting device (3) and to said requested emission property data.