A sunshade system comprising a control system, a control system for an awning, and a method for controlling an awning operator.

DESCRIPTION The present invention, according to a first aspect thereof, relates to a sunshade system comprising an awning which, when mounted to a building, can be moved by means of an operator between at least one operative position, in which it screens at least a part of the building at least partially from exterior light entering through a light passage, and a non-operative position, in which it does not, at least substantially, screen the building from exterior light entering through a light passage, a control system comprising a control unit for controlling the operator and a sensor for measuring a light value and sending a signal representative of the sensor's measurement to the control unit.

Awnings comprising an operator which is controlled by means of a light-sensitive sensor are generally known. DE 29 924 615 U1 discloses such a device comprising a solar sensor in the form of a light-sensitive resistor, photocell or solar cell, which may be provided directly on the printed circuit board of the system inside the sensor housing or in the form of a light-sensitive element on the outer side of the housing. The setting of the awning is adjusted in dependence on input values as determined, such as the intensity of the sunlight.

A drawback of such a device is that the setting of the awning can be adjusted by means of the control unit and the operator in dependence on the intensity of the light measured by the sensor, but not in dependence on the discomfort caused by incident light in the building. Comparatively horizontal incident light having a relatively low intensity, for example, may cause much more discomfort at a workplace, for example a visual display workplace, than relatively vertical incident light having a relatively high intensity.

Consequently it is an object of the present invention to provide a sunshade system as referred to in the introduction in which the awning operator is controlled in dependence on the degree of discomfort that incident light causes at a workplace provided with a visual display unit, or which in any case takes the degree of discomfort to a user of the visual display unit caused by incident light more into account than does the known sunshade system. This object is accomplished by the present invention in that the sensor is a reflection sensor for measuring reflection on

and/or by a visual display unit. Reflection is very objectionable to a user of a visual display unit, such as a computer screen, a television screen or any other type of display screen. After all, reflection makes it difficult or even altogether impossible for a user to discern an image being displayed on the screen. By measuring the reflection of light that enters the building on or near the visual display unit and adjust the awning in dependence thereon, the setting of the awning is adjusted in dependence on the actual degree of discomfort a user of the visual display screen experiences from said reflection. The object of the present invention is thus accomplished. A reflection sensor measures the intensity of direct light and, in doing so, takes the ambient light into account. Within this context, the term "direct light" does not necessarily mean direct incident sunlight, but light whose rays are more or less directed. That is, a user of the visual display unit will also regard sunlight which is mirrored in a particular direction by a mirroring surface (the term "reflection" as used herein concerns the reflection of light on a visual display unit, the term "mirroring" as used herein is understood to mean the mirroring of light before said light is incident on a visual display unit) and is incident upon a visual display unit as direct light which may cause reflection. Said mirroring may take place outside a workroom, for example by a mirroring facade of another building, but it may also take place inside the workroom, for example by a desktop. Sensors can measure reflection in various manners. According to a known manner, a combination of light-sensitive sensors is used, which sensors each measure the intensity of light from a different angle of incidence. On the basis of the measured values, the intensity of (diffuse) ambient light and, if present, the intensity and angle of incidence of direct light can be calculated.

Measuring reflection on and/όr by a visual display unit has the advantage that the control system of the sunshade system responds to the situation at the workplace, or the actual degree of discomfort a user experiences while operating the visual display unit. Known systems, a few of which will be discussed hereinafter, which aim at reducing the degree of discomfort caused by sunlight at a workplace, are based either on measuring the amount of light in a workroom and/or on measuring the angle of incidence of sunlight at a position spaced from the work and indirectly determining whether the incident sunlight may cause any discomfort at a workplace. In this way the influence of other variables that may affect the degree

of discomfort caused by incident sunlight is excluded. When the room in which a workplace is arranged is rearranged, for example, the control system needs to be reprogrammed to adapt the control system of the sunshade system to the altered conditions. This is necessary, for example, when the visual display unit is placed at a different location (even a minor shift of the position of the visual display unit by a user may make it necessary to change the setting) or turned, but also when another workplace is installed or a relatively large piece of furniture, such as a cabinet, is installed, or moved, as a result of which sunlight coming in at a specific angle of incidence through a light passage leads to a different degree of discomfort being experienced at the workplace. Another influencing factor may be the placement of mirroring objects in a room. The known systems will not take this factor into account, because it is not a variable that is included in the programming of the control system. The invention even makes it possible to have the control system respond to reflection on a laptop computer or other mobile visual display unit, whose position is not fixed, therefore. Furthermore, the control system can be programmed so that it will only take into account visual display units which are "on" or "standby", or the sensor of a visual display unit can be deactivated when a visual display unit is "off" or "standby". When combined with a location sensor, it can be determined in that case which one of a number of awnings is to be driven in case incident sunlight is found to be objectionable. In all these cases the known systems exhibit shortcomings.

An advantage of the invention is furthermore the fact that an awning will not take up the operative position when relatively much light enters the building whilst this is not objectionable to users, not even if said incident light is direct light. The fact is that an awning in the operative position not only keeps out the light but, as a consequence thereof, also heat. An awning which is maintained in the operative position unnecessarily can thus lead to a needlessly high energy consumption for heating the building in question. The present invention in addition has an additional energy-saving effect, therefore. From US 5,663,621 A an autonomously operating automatic system for blocking daylight is known. The system is capable of regulating the amount of light being admitted through a window without requiring an illuminance sensor, a sensor for detecting sunlight or a sensor for measuring the angle of incidence of sunlight. More than that, US 5,663,621 teaches the reader that the use of interior

illuminance sensors and/or sensors for measuring the angle of incidence of light should be avoided, because they require the use of complex control systems. According to the embodiment described in US 5,663,621 , the lighting level outside a building is measured, and the value in question is combined with variables stored in a memory of a control unit for the purpose of controlling sunshade means. This system is also described in publication XP 002463544 entitled "Developing integrated envelope and lighting systems for commercial buildings" by Lawrence Berkeley Labatory, California.

In US 5,237,169 a system is described in which the lighting level inside a building is measured, on the basis of which measurement a determination is made if, and if so, how much artificial light is to be added to obtain a sufficient lighting level. Reflection on a visual display unit as such is not discussed in said document, either.

From WO 02/066763 A1 there is known a system for suppressing solar radiation incident on a building. The system comprises a sunshade element comprising at least one solar energy converter and a control element which controls the position of the sunshade element on the basis of the direction of incident sunrays for the purpose of achieving a maximum conversion of solar energy into a form of energy which can be consumed and/or stored. In a preferred embodiment of the present invention, the reflection sensor comprises light-emitting diodes (LEDs) which respond to incident light. A typical feature of light-emitting diodes is that they generate electricity in deactivated state when a specific amount of light is incident thereon. An LED can thus be used as a light sensor. By positioning a number of LEDs at different angles relative to each other, for example on a visual display unit, the angle of incidence of the light can be determined from the differences in the measured amounts of incident light for each LED. An advantage of this type of sensor, for example an LED3X LED Sensor Electronic Tracker with H-Bridge Drive, is that is can be of comparatively compact design. This makes it possible to fit a visual display unit with such a sensor in a simple, non-objectionable manner.

In an alternative preferred embodiment according to the present invention, the reflection sensor comprises a number of light dependent resistors. Analogously to LEDs, a light-sensitive resistor can be used as a light sensor, and the angle of incidence of the light can be determined by using a number of light-

sensitive resistors arranged at different angles relative to each other. Such sensors, too, can be of comparatively compact design.

In yet another embodiment of the present invention, the reflection sensor comprises photovoltaic elements, also called solar cells. Said elements, too, can be used, in the manner as discussed above with regard to the LEDs, as light sensors and as sensors for determining the angle of incidence of the light. Said sensors are available as film-based sensors, so that they can be very flat.

It would be beyond the scope of the present patent application to give an exhaustive enumeration of suitable sensors. Thus it would be possible to use the so-called Digital Solar Altitude Detector, which is currently being used in space travel, but which is very expensive (so far).

The sunshade system preferably comprises a timer, for example in the control unit. Using the timer, an interval can be set for the reflection measurement or for the response time to a sensor measurement. In this way frequent switching between the operative position and the non-operative position of the awning is prevented, because the degree of reflection on or by the visual display unit will decrease in said at least one operative position of the awning, of course, possibly resulting in the awning being returned to the non-operative position, in which the degree of reflection would require the awning being moved to the operative position again. This can also be effected by setting a relatively high threshold value for the reflection, which, upon being exceeded, causes the drive unit to move the awning from the non-operative position to the at least one operative position, and a relatively low threshold value for the reflection, below which value the drive unit will move the awning from the at least one operative position to the non- operative position. The timer can also be set to move the awnings jointly to the same position during specific periods, for example outside working hours, possibly in dependence on the reflection measured by a sensor.

In a preferred embodiment of the present invention, the sensor is a physical sensor which is or can be positioned on or near a visual display unit. An advantage of this is that if the sensor is positioned near the visual display unit, it can remain in use when the visual display unit is exchanged for another visual display unit. When the sensor is detachably provided on a visual display unit, the sensor can be placed on the new visual display unit when the visual display unit is being replaced.

In a preferred embodiment of the present invention, the sensor is integrated in a visual display unit so as to make it possible to carry out a measurement on the display portion of a visual display unit. Integrated sensors, or at least integratable sensors capable of measuring the reflection at different positions on the visual display unit, are commercially available.

It is preferable in that regard if the sensor is integrated in the visual display unit as software. Integrated sensors, for example in the form of software, which are capable of measuring the reflection at different positions on the visual display unit, are available in the market. In order to be able to adjust the awnings of a building in dependence on the requirements, it is advantageous if the sunshade system comprises two or more awnings which can be operated independently of each other in response to measurements by different sensors.

The present invention, according to a second aspect thereof, relates to a control system for an operator of an awning on a building, comprising a control unit and a sensor for measuring a light value and sending a signal representative of the sensor measurement to the control unit for controlling the operator in dependence on the signal from the sensor, wherein said sensor is a reflection sensor arranged for measuring reflection on and/or by a visual display unit. The problem underlying the invention, the object, an advantage and preferred embodiments of the invention have already been discussed in the foregoing in relation to the sunshade system according to the first aspect of the invention.

The present invention, according to a third aspect thereof, relates to a method for controlling an operator to move at least one awning on a building between an operative position and a non-operative position, comprising the steps of measuring a light value in the building, sending a signal representative of the measured light value to a control unit, and controlling the operator of said at least one awning in dependence on said signal, wherein the step of measuring the light value comprises measuring the reflection on or by a visual display unit. Also in this case the problem underlying the invention, the object, an advantage and preferred embodiments of the invention have already been discussed in the foregoing in relation to the sunshade system according to the first aspect of the invention.

The present invention will be explained hereinafter on the basis of a description of (the operation of) an example of a sunshade system according to the

present invention.

A control system for an operator of a number of awnings mounted to an office building is prepared for receiving signals from reflection sensors provided on visual display units inside the building. The control system is furthermore prepared for receiving information about the state ("on", "off" or "standby") of a number of visual display units inside the office building and about the position of mobile visual display units (for selecting the awning to be controlled in dependence on said position). Possibly, the control system comprises diary/clock information for determining working hours. In this example, the awnings can be controlled independently of each other by the control unit. The visual display units in a room which can be protected by an awning are all fitted with a reflection sensor, which sends a signal, whether or not wirelessly, to the control unit. The control unit is set so that the signals from the sensors are processed in dependence on the position relative to the various awnings. This need not be a static position, but the image can be adjusted as the position of the sun shifts.

When an awning is in the non-operative position and at least one of the sensors in a particular room measures a reflection value higher than a preset maximum value, this will result in the control unit driving the awning or the awnings associated with the room in question to an operative position. When the awning is in an operative position, and all the sensors in a particular room measure a reflection value lower than a preset minimum value, this will result in the control unit driving the awning or the awnings associated with the room in question to a non-operative position. The control unit is provided with a timer, which prevents the operator of the awning from being driven within a preset period, for example a quarter of an hour or an hour after the awning has moved to the operative position. This is done in order to prevent the system from responding (too) nervously to minor changes in the prevailing conditions.

In the preceding paragraph one embodiment of a sunshade system according to the present invention has been discussed by way of example. However, this example by no means has a limitative effect on the scope of the present invention, which is determined by the appended claims. Various variants which are obvious to the skilled person are possible. Thus it is conceivable to use more than one control system - such as 1 : 1 , 1 : n, or m : 1 control systems - in the case of a sunshade system comprising a large number of awnings and a large number of

visual display units fitted with sensors, which are distributed over the several rooms. Furthermore, the control of the awnings, in addition to being dependent on the signals from the reflection sensors, may also depend in part on signals from other sensors, for example wind sensors, which help limit the risk of damage to awnings, or from sensors that measure the amount of incident light. Moreover, one or more further operative positions between said at least one operative position and said non-operative position of the awning are possible, and the awning may also be driven between a further operative position and said at least one operative position and/or said non-operative position by the control unit, for example in dependence on the signal from the sensor. Besides awnings, also other types of sunshade means, such as louvres or Venetian blinds may be used, which sunshade means may be disposed either inside the building or outside the building.