DIJKSTRA, Jacob (AE Eindhoven, NL-5656, NL)
BRON, Andries (AE Eindhoven, NL-5656, NL)
DEKKER, Martijn, J. (AE Eindhoven, NL-5656, NL)
WERKMAN, Pieter, J. (AE Eindhoven, NL-5656, NL)
HOEXUM, Everhardus, J. (AE Eindhoven, NL-5656, NL)
DIJKSTRA, Jacob (AE Eindhoven, NL-5656, NL)
BRON, Andries (AE Eindhoven, NL-5656, NL)
DEKKER, Martijn, J. (AE Eindhoven, NL-5656, NL)
WERKMAN, Pieter, J. (AE Eindhoven, NL-5656, NL)
CLAIMS:
1. A wake-up system for awaking a person by increasing the light intensity, comprising a main light source (4) and control means for gradually increasing the light intensity of the main light source (4) to its maximum light intensity of at least 400 lumen, characterized in that the main light source comprises a gas discharge lamp (4), and in that an auxiliary light source is present comprising a lamp (5) having a lower maximum light intensity than the main light source (4), which lamp (5) can be dimmed to a minimum light intensity at which no light radiation is emitted, and the control means can control the light intensity of the main light source (4) as well as the light intensity of the auxiliary light source (5).
2. A wake-up system as claimed in claim 1, characterized in that the gas discharge lamp (4) of the main light source is a compact fluorescent lamp (4).
3. A wake-up system as claimed in claim 1, characterized in that the main light source comprises only one lamp (4).
4. A wake-up system as claimed in claim 1, characterized in that the gas discharge lamp (4) of the main light source has a maximum light intensity of at least 600 lumen.
5. A wake-up system as claimed in claim 1, characterized in that the lamp (5) of the auxiliary light source has a maximum light intensity of less than 400 lumen, preferably less than 200 lumen, more preferably less than 100 lumen.
6. A wake-up system as claimed in claim 1, characterized in that the lamp (5) of the auxiliary light source is an incandescent lamp (5).
7. A wake-up system as claimed in claim 1, characterized in that the lamp (5) of the auxiliary light source is a LED (Light Emitting Diode), and, preferably, the auxiliary light source comprises a number of LEDs.
8. A wake-up system as claimed in claim 1, characterized in that the control means are programmed in such a manner that the main light source (4) is switched on with a light intensity of less than 15%, and preferably less than 10%, of the actual light intensity of the auxiliary light source (5).
9. A wake-up system as claimed in claim 1, characterized in that the light color of the auxiliary light source (5) differs from the light color of the main light source (4).
10. A method of awaking a person, in which the light intensity of a main light source (4) is gradually increased from a minimum light intensity to a maximum light intensity, characterized in that an auxiliary light source (5) is switched on when the wake-up cycle is started, wherein the light intensity of the auxiliary light source (5) is gradually increased from 0 lumen to at least 2 lumen, and wherein the main light source comprises a gas discharge lamp (4), which lamp (4) is switched on after the auxiliary light source (5) has reached a predetermined light intensity. |
A wake-up system and a method of awaking a person by means of light
FIELD OF THE INVENTION
The invention is related to a wake-up system for awaking a person by increasing the light intensity, comprising a main light source and control means for gradually increasing the light intensity of the main light source to its maximum light intensity of at least 400 lumen. In general, the system will also produce a sound signal at the end of the wake-up cycle. The light intensity of a light source is defined in lumen (Im), being the SI unit of luminous flux.
BACKGROUND OF THE INVENTION In general, the system for awaking a person who is asleep includes an alarm clock coupled to control means for controlling the electric power supplied to the light source. After the wake-up cycle is started, the light intensity emitted by the light source is slowly, smoothly and gradually increased. The time interval over which the light intensity increases is a predetermined period of time, or can be selectable by the user of the system. It will usually be in the range of thirty minutes to some hours. The final light intensity of the wake- up system is selectable by the user, or has a predetermined value. The control means for increasing the light intensity are designed to ensure that the light intensity increases smoothly, especially at the beginning of the wake-up cycle. The increase of the light intensity is slower when the light is very dim than when the light intensity is bright, because the human eye is more sensitive to light intensity variations when the background light level is low than when it is high. At the end of the wake-up cycle the system produces a sound signal to make sure that the person to be awaked knows that the wake-up cycle is over, or to awake that person in case he is still sleeping.
The sensitivity of the human eyes to light and to variations in light intensity depends upon the state of the eyes, the background light, and other factors such as the wavelength of the light. When the eyes have become adjusted to the dark during a person's sleep, the eye is at least 10,000 times more sensitive to light than during the day, when the eyes are not adapted to the dark. The dark-adapted eyes can sense even minute changes in
light intensity when the background light levels are very low, even when the person in question is in a subconscious state of mind.
When the eyelids are closed and the person is asleep, a very faint light can be sensed by the dark-adapted eyes. As the light level increases, very small changes in intensity are sensed by the eye, because it is still dark-adapted, and the rate of change in the body's chemistry and internal wake-up clock of the person can adjust to the gradually increasing intensity of the light. Therefore, it is most important that the increase in light intensity is very smooth, and preferably slow, in particular at the very beginning of the wake-up cycle. The light intensity preferably increases from zero lumen at the start. It is known to make use of one or more incandescent lamps as main light source. An incandescent lamp has the advantage that its light intensity is very accurately controllable, also when the light intensity is very low. So, the increasing light intensity of an incandescent lamp can be easily controlled, starting from zero lumen.
A disadvantage of the use of an incandescent lamp as the main light source in the wake-up system is the relatively low efficiency of the lamp, whereby a relatively large portion of the power supplied to the lamp is converted into heat. Because an incandescent lamp of at least 7OW, or even more than 10OW, is applied as the light source in the wake-up system, measures have to be taken for cooling the system, and cooling is preferably performed by means of free convection of ambient air, in order to avoid noise. Therefore, the dimensions of such a wake-up system are relatively large.
SUMMARY OF THE INVENTION
An object of the invention is to provide a wake-up system and a method of awaking a person by increasing the light intensity, comprising a main light source and control means for gradually increasing the light intensity, wherein the dimensions of the system are relatively small.
Another object of the invention is to provide a wake-up system and a method of awaking a person by increasing the light intensity, comprising a main light source and control means for gradually increasing the light intensity, wherein the electric power supplied to the system is relatively low.
Another object of the invention is a wake-up system and a method of awaking a person by increasing the light intensity, comprising a main light source and control means for gradually increasing the light intensity, wherein the color of the light radiation of the system can change during the wake-up cycle.
To accomplish one or more of these objects, the main light source comprises a gas discharge lamp, and an auxiliary light source is present comprising a lamp having a lower maximum light intensity than the main light source, which lamp can be dimmed to a minimum light intensity, at which no light radiation is emitted, and the control means can control the light intensity of the main light source as well as the light intensity of the auxiliary light source. Preferably, the gas discharge lamp of the main light source is a compact fluorescent lamp. In general, a compact fluorescent lamp has a curved tubular burner, so that its dimensions are relatively small. Often, the lamp is designed in such a manner that it can replace a standard incandescent lamp. A gas discharge lamp has a high efficiency, about five times higher than an incandescent lamp, so that the heat production of the lamp is relatively low. Therefore, no special cooling measures for cooling the wake-up system are required. Furthermore, if a compact fluorescent lamp is used as the main light source, the dimensions of the wake-up system can be relatively small. However, a usual gas discharge lamp cannot be dimmed to a level where no light radiation is emitted. When the lamp is switched on, there will always be a certain minimum amount of light emission of the lamp, which light emission has a light intensity much higher than an acceptable minimum light intensity of a wake-up system. To overcome that problem, an auxiliary light source is present, which auxiliary light source comprises a lamp that is able to start at a level where no light radiation is emitted, and that can be controlled by the control means in such a manner that its light intensity increases gradually from that level (zero lumen) to its maximum light intensity.
So, according to the invention, the wake-up cycle starts by switching on the auxiliary light source and subsequently increasing the light intensity of the auxiliary light source from zero lumen to its maximum light intensity. Then, the main light source is switched on and starts emitting its minimum light intensity. If the minimum light intensity of the main light source is low compared to the maximum light intensity of the auxiliary light source, for example about 10% or less, then the step in the increase of the light intensity of the wake-up system will not disturb the wake-up process of the person to be awaked. After the main light source is started, its light intensity is increased gradually by the control means, and the light intensity of the auxiliary light source can be gradually decreased to zero lumen. Of course, the total light emission of the wake-up system has to be gradually increased. It is also possible to maintain the maximum light intensity of the auxiliary light source during the further part of the wake-up cycle. In another embodiment, the auxiliary light source is
switched off at the moment that the main light source is switched on. Such simultaneous switching can be controlled by adequate control means.
The main light source as well as the auxiliary light source of the wake-up system may comprise more than one lamp. In particular, if the auxiliary light source comprises LEDs, a plurality of LEDs is preferred. In a preferred embodiment, the main light source comprises only one lamp, in order to limit the dimensions of the wake-up system. And preferably, also the auxiliary light source comprises one lamp.
In a preferred embodiment, the gas discharge lamp of the main light source has a maximum light intensity of more than 600 lumen. Such a high maximum light intensity can be used without a need for special cooling measures, because of the high efficiency of the gas discharge lamp.
Preferably, the lamp of the auxiliary light source has a maximum light intensity of less than 400 lumen, preferably less than 200 lumen, and more preferably less than 100 lumen. When using a low-power lamp as the auxiliary light source, it may be a relatively inefficient lamp such as an incandescent lamp, without a need for special cooling measures. However, the maximum light intensity of the auxiliary light source is preferably not too low, in order to make it possible that the main light source can be switched on without disturbing the wake-up cycle.
Any kind of lamp can be used as an auxiliary light source, provided that its minimum light intensity is low enough to start the wake-up cycle. Even a small fluorescent lamp can be used. But, in a preferred embodiment, the lamp of the auxiliary light source is an incandescent lamp, and in another preferred embodiment, the lamp of the auxiliary light source is a LED (Light Emitting Diode), and preferably, the auxiliary light source comprises a number of LEDs. The light intensity of these lamps can be easily controlled, starting from zero lumen.
In a preferred embodiment, the control means are programmed in such a manner that the main light source is switched on with a light intensity of less than 15%, preferably less than 10%, of the actual light intensity of the auxiliary light source, i.e. the light intensity at the moment that the main light source is switched on. As said before, such a relatively small step in the increase of the light intensity of the wake-up system should not disturb the wake-up cycle.
In a preferred embodiment, the light color of the auxiliary light source differs from the light color of the main light source. The auxiliary light source may emit a more amber and/or red and/or orange light radiation than the main light source, so that the light
color emitted by the wake-up system changes during the wake-up cycle. This color change imitates more or less the color change of the rising sun.
Furthermore, the invention is related to a method of awaking a person, in which method the light intensity of a main light source is gradually increased from a minimum light intensity to a maximum light intensity, an auxiliary light source is switched on when the wake-up cycle is started, and the light intensity of the auxiliary light source is gradually increased from substantially zero lumen to at least 2 lumen, wherein the main light source comprises a gas discharge lamp, which lamp is switched on after the auxiliary light source has reached a predetermined light intensity, preferably its maximum light intensity.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be further elucidated by means of a description of an embodiment of the wake-up system comprising a main light source and an auxiliary light source and control means for gradually increasing the light intensity, said description making reference to the drawing wherein:
Figure 1 is a diagrammatic perspective view of an embodiment of a wake-up system according to the invention.
DETAILED DESCRIPTION OF THE INVENTION The embodiment of the wake-up system according to the invention shown in
Figure 1 comprises a base part 1 that can be placed on a table or the like. The base part 1 comprises control means (inside the base part 1) and a display 2 surrounded by buttons 3 to set and adjust the control means. The clock time and the wake-up time, and other data, are shown on the display 2. The clock time, the wake-up time, the maximum light intensity, and other settings of the control means can be adjusted by means of the buttons 3.
On top of the base part 1, a compact fluorescent lamp 4 and an incandescent lamp 5 are mounted. Both lamps are surrounded by a translucent cover 6, which cover 6 is represented in the drawing in a sectional view, so that the two lamps 4, 5 are visible. The compact fluorescent lamp 4 is the main light source of the wake-up lamp and the incandescent lamp 5 is the auxiliary light source. In the shown embodiment, the lamp 4 is a 17 Watt compact fluorescent lamp having a maximum light intensity of about 1,000 lumen. The lamp 5 is a 40 Watt incandescent lamp having a maximum light intensity of about 400 lumen.
When the wake-up cycle starts, the incandescent lamp 5 is switched on and the light intensity is gradually increased by the control means from zero lumen to the maximum light intensity of 200 lumen. Then the compact fluorescent lamp is switched on at its minimum light intensity, being in this embodiment about 20 lumen. As a result, the light intensity emitted by the wake-up system is increased by a relatively small step of about 10% of the actual light intensity of the wake-up system, which step is too small to disturb the wake-up cycle.
In the shown embodiment of the wake-up system, the light intensity of the incandescent lamp 5 of the auxiliary light source will be gradually decreased by the control means after the compact fluorescent lamp 4 of the main light source is switched on. The light intensity of compact fluorescent lamp 4 is gradually increased more than the decrease of the light intensity of the incandescent lamp 5, so that the total light emission of the wake-up system increases gradually according to the programmed wake-up cycle.
In the shown embodiment, the incandescent lamp 5 of the auxiliary light source has a more amber light color than the compact fluorescent lamp 4 of the main light source. Therefore, the color of the light radiation of the wake-up system changes during the wake-up cycle, approximately similarly to the change of the light radiation of the sun during sunrise.
The wake-up system can be placed on a table near the bed of the person to be awaked. Means for supplying electric power to the system are present, but not shown in the figure. The described embodiment of the wake-up system is only an example of a system according to the invention; many other embodiments are possible.