Window blind

FIELD OF THE INVENTION

The present invention relates to a window blind facing an interior space, and in particular to a window blind adapted to automatically regulate the amount of light provided to an interior space.

BACKGROUND OF THE INVENTION

Comfortable working and leisure environments in e.g. buildings, automobiles, or any other interior applications, require adequate interior lighting. Interior lighting may be provided by light entering through a window, such as light emitted from the sun, or by artificial lighting, such as any kind of lamps. During sunny days of a year, e.g. during summers, window blinds are often used at windows for shielding interior spaces from sunlight. A conventional window blind allows flexible adjustment of the light coming through a window by tilting slats or lamellas of the window blind. However, it is difficult to continuously provide adequate lighting conditions in an interior space using a conventional window blind. In addition, the light provided by a conventional window blind may be insufficient for achieving an adequate and comfortable interior lighting.

Thus, there is a need for providing new devices and systems that would overcome these problems.

SUMMARY OF THE INVENTION

An object of the present invention is to wholly or partly overcome the above disadvantages and drawbacks of the prior art and to provide a more efficient alternative to the above techniques and prior art. More specifically, it is an object of the present invention to provide a window blind enabling a continuously appropriate interior lighting. The present invention is based on an insight that a photo detecting means may be arranged at one of the slats of a window blind, which window blind and photo detecting means face an interior space, in order to detect light intensity in the interior space.

Hence, according to a first aspect of the present invention, a window blind facing an interior space is provided. The window blind comprises a support member and a

plurality of slats connected to the support member by means of at least one hanging system. The hanging system is adapted to, when the window blind is in a deployed state, suspendly support the slats. At least one of the slats comprises at least one photo detecting means for detecting a level of light intensity in the interior space, and an amount of light provided by the window blind is regulated in response to the detected light intensity.

According to a second aspect of the present invention, a method as defined by appended claim 12 is provided.

The inventive window blind and method are advantageous in that the light intensity in the interior space continuously can be detected, thereby enabling a continuous control of the light provided by the window blind. Such window blind can then provide an adequate level of illumination, which is adapted to e.g. a particular situation in the interior space.

In an embodiment, a tilt angle of the slats to the support member is regulated in response to the detected light intensity. In particular, the tilt angle formed between each of the slats and the support member may vary from 0°, which corresponds to an opened position in which the slats are parallel to the support member, to 90°, which corresponds to a closed position in which the slats are perpendicular to the support member.

The window blind may then be provided with a regulator for controlling the tilt angle of each of the slats in response to the detected light intensity and a predetermined light intensity. The predetermined light intensity may be set by an user, which, depending on his activity in the interior space, would prefer more or less light intensity or illumination. The regulator would then control the rotation of the slats such that the window blind provides an amount of light equivalent to the predetermined light intensity.

In another embodiment, at least one of the slats may comprise at least one lighting means, which is advantageous in the case where the light provided by the window blind, using e.g. sunlight, is not sufficient. This solution is also advantageous as it provides a device which both can shield and illuminate an interior space, without requiring any additional space.

A control signal may then be provided to the lighting means from the regulator in response to the detected light intensity, thereby controlling the amount of light provided to the interior space.

According to one embodiment, the lighting means and the photo detecting means are combined in a single component, which is advantageous since this reduces the total weight of the window blind.

The lighting means may preferably be an organic light emitting diode (OLED), which is advantageous as OLEDs are very efficient light sources.

In a further embodiment, at least one of the slats may comprise semiconductor material, which is advantageous since the photo detecting means and the lighting means may directly be manufactured and incorporated in the slat. In this embodiment, the semiconductor material or substrate in which the lighting means and the photo detecting means are fabricated is equivalent to the material of the slat.

In a first alternative, a predetermined light intensity may be set at the regulator, which, in response to the detected light intensity, controls the amount of light provided to the interior space. Normally, a user would then select a value corresponding to a light intensity. However, this value may for instance be expressed as a percentage. The amount of light provided in the interior space is then maintained constant by the regulator until an user varies the predetermined value. In another alternative, the regulator may be operated by a remote controller, which is advantageous since a person located in the interior space may adjust the interior lighting from her own position at any time, without having to go to the regulator.

Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims. Those skilled in the art realize that different features of the present invention can be combined to create embodiments other than those described in the following.

In the present application, a slat is defined as a thin rectangular panel where the short side of the rectangular panel corresponds to its width, and the long side of the rectangular panel corresponds to its length, the thickness of the slat typically being much less than the width and the length of the slat. A slat may be flat or curved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non- limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, in which:

Figure 1 shows a cross-sectional view of a window blind according to an embodiment of the present invention, and

Figure 2 shows a cross-sectional view of a window blind according to another embodiment of the present invention.

All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested.

DETAILED DESCRIPTION OF EMBODIMENTS

With reference to figure 1, a first embodiment of the present invention will be described below. Figure 1 shows a cross-sectional view of a window blind 1 comprising a support member 15 and a plurality of slats or lamellas 1 Ia-I Id connected to the support member 15 by means of a hanging system 12. The window blind may be arranged at a window facing an interior space. As examples, such a window may separate an exterior space from an interior space, such as an office room, or may separate two interior spaces, such as two adjacent office rooms. At least one of the slats 1 Ia-I Id, such as slat 1 Ic for example, comprises a photo detecting means 14 for detecting a level of light intensity in the interior space. Although each of the slats of the window blind 1 shown in Figure 1 comprises a photo detecting means, it is sufficient if at least one of the slats of the window blind comprises a photo detecting means. It is therefore not necessary that each of the slats comprises a photo detecting means. The light provided by the window blind 1 may then be regulated in response to the detected light intensity. If more than one photo detecting means is employed, the light provided by the window blind 1 is regulated in response to a computation of the light intensities detected by the photo detecting means.

The window blind 1 shown in Figure 1 is in its deployed state, i.e. the slats 1 Ia-I Id are suspended at the hanging system 12. In the deployed state, if the slats 1 Ia-I Id are in an opened position, i.e. in a position parallel to the support member 15 with a tilt angle of 0°, the distance between two neighboring slats along the support lines of the hanging system 12 is approximately equal to the width of a slat. The state of the window blind 1 may, however, vary from a totally deployed state, in which the window blind would normally, but not necessarily, cover a whole window, to an undeployed state, in which the slats of the window blind all are compressed together, thereby allowing light to freely enter the interior space and forming a single block either at the top, the bottom or a side of the window. The photo detecting means 14 may be a solid state device, preferably a photodiode, and more preferably a photodiode comprising inorganic material.

Figure 2 shows a cross-sectional view of a window blind 2 according to another embodiment of the present invention. In Figures 2a and 2b, the position of the slats 1 Ia-I Id are defined by a tilt angle CC, which is the angle formed between the support member 15 and the slats 1 Ia-I Id. The slats 1 Ia-I Id shown in Figure 2a are not completely opened but are in a more opened position than the slats shown in Figure 2b. A completely opened position would correspond to a tilt angle equal to 0° while a closed position would correspond to a tilt angle equal to 90° or approximately 90°. Note that the so-called "opened" position does not necessarily correspond to a position at which a maximum amount of light passes through the window blind. The variation of the tilt angle enables to control the amount of light provided by the window blind since, at a given time of the day, the amount of light passing through the window blind depends on the tilt angle.

In response to the light intensity detected by the photo detecting means 14 arranged at the slats 1 Ia-I Id, the orientation of the slats, i.e. the tilt angle of the slats, is regulated. Although the regulation may be made manually, it is preferable to implement an automatic regulation of the tilt angle of the slats 1 Ia-I Id of the window blind 1. For this purpose, a regulator 16, at which a predetermined level of light intensity in the interior space may be set, is arranged at the window blind. In a preferred embodiment, the regulator 16 is arranged at the support member 15. The regulator 16 is then adapted to receive the detected level of light intensity from the photo detecting means 14 and to control the tilt angle of the slats 1 Ia-I Id in response to the detected level of light intensity and the predetermined level of light intensity. As a result, the slats 1 Ia-I Id are tilted such that an amount of light equivalent to the predetermined level of light intensity is provided to the interior space by the window blind 1. If the amount of light provided by the window blind still is not sufficient by regulation of the tilt angle of the slats 1 Ia-I Id, the regulator 16 may control the slats 1 Ia-I Id such that the window blind is in an undeployed state, thus allowing all light to freely enter through the window at which the window blind may be arranged.

According to one embodiment, the regulator 16 may be adapted to output a control signal to regulate the tilt angle of the slats 1 Ia-I Id. The control signal may be provided to the slats 1 Ia-I Id by means of the suspension lines of the hanging system 12, which suspension lines comprises connection lines or power lines. Alternatively, a wireless connection may be established between the regulator 16 and the slats 1 Ia-I Id to provide the control signal to the slats 1 Ia-I Id.

In an embodiment, a remote controller 17 may be used to operate the regulator 16.

Referring to Figures 1 and 2, a lighting means 13 may be arranged at the slats 1 Ia-I Id of the window blind 1 and may be controlled in response to the detected light intensity. This is particularly advantageous if the maximum amount of light provided by the window blind 1, using an optimal tilt angle of the slats, or the maximum amount of light provided through the window when the window blind is undeployed, is not sufficient.

The lighting means 13 may also be controlled by the regulator 16. The control of the lighting means 13 may be performed in three different manners. In a first alternative, the lighting means arranged at the slats 1 Ia-I Id may be controlled individually, thereby enabling the display of any geometrical figures or pattern at the window blind 1. In a second alternative, the lighting means of a particular slat may be controlled all together and not necessarily in the same manner as the lighting means of another slat. In a third alternative, all the lighting means are controlled in the same manner, thereby providing an homogeneous monochromatic display.

In an embodiment, the energy required at the slats to control the lighting means 13 or the tilt angle of the slats is provided by means of the support lines of the hanging system 12.

It will be appreciated by a person skilled in the art that any type of lighting means may be used. In preferred embodiments, however, solid state devices and in particular light emitting diodes are used. These types of light sources are advantageous since they are small and therefore easily incorporated at the slats of the window blind. In particular, organic light emitting diodes (OLEDs) may be employed. As OLEDs can be made very thin, with a thickness of e.g. 10 μm, the size of the window blind is not so much increased. Further, OLEDs are very efficient light sources, with an efficiency comparable to the efficiency of fluorescent lamps.

In yet a further embodiment, the lighting means 13 may be a combination of red, green and blue diodes for emitting white light from the window blind. It will be appreciated by a person skilled in the art that the lighting means at the slats of the window blind may have any geometrical arrangement in order to achieve any preferential illuminating arrangement or pattern. Depending on the application, the density of light emitting diodes (number of diodes per unit area) may vary.

In yet a further embodiment, the regulator 16 may be employed to control the amount of light provided by the lighting means 13 arranged at the slats 1 Ia-I Id. in particular,

the regulator 16 may be employed to achieve smooth transitions from daylight to light only provided by the lighting means 13 of the window blind 1. In particular, the regulator 16 may control the lighting means 13 to compensate for light fading when daylight becomes insufficient. The use of light emitting diodes as light emitting means 13 in combination with the regulator 16 enables seamless transitions from daylight to artificial lighting since light emitting diodes are dimmable.

It is, for instance, common that constant light levels are used in working environments and that a smooth transition between varying daylight conditions may be difficult to achieve. Using a window blind in accordance with embodiments of the present invention in e.g. an office building provides comfortable interior lighting conditions to people working in the building. When daylight is fading, people can switch on the light from the window blind. The lighting means integrated in the window blind, through which natural daylight also enters the building, compensate for variations of the exterior light conditions. Smooth transitions can be obtained by means of the dimmable property of light emitting diodes controlled by the regulator 16.

In a further embodiment, at least one of the slats may comprise semiconductor material in which the photo detecting means 14 and the lighting means 13 may be manufactured. In this embodiment, the semiconductor material or substrate in which the lighting means 13 and the photo detecting means 14 are fabricated is equivalent to the material of the slat 1 Ia-I Id. It is preferable that the substrate is reflective to ensure that the slats 1 Ia-I Id may be used to shield the interior space from external light sources, such as the sun. The substrate may be selected such that it reflects infrared light, thereby limiting the amount of infrared light entering the interior space. Further, the substrate may be selected such that it keeps a high level of light intensity in the interior space. Although the window blind 1 shown in Figure 1 operates vertically, the window blind according to the present invention may also operate horizontally or in any other orientations.

The present invention is applicable in any lighting applications such as office buildings, individual homes, greenhouses, ambient lighting for special interior effects, automobile lighting for e.g. windows in cars, busses, trains, and/or for compensation of the fading of the daylight.

Although the invention above has been described in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several

modifications are conceivable without departing from the scope of the invention as defined by the following claims.