Patent Publication Number: US-2023145323-A1

Title: Virtual window device

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to lighting devices in the form of virtual window devices, or so called artificial windows, which are capable of providing a realistic appearance of authentic windows. 
     BACKGROUND OF THE INVENTION 
     It is often undesired that rooms or areas of office spaces, homes, stores, etc., lack a source of outside light. For example, it may be preferred to provide a source of outside light in basements for an increased attractiveness of the space and/or for an increased sense of well-being. Furthermore, offices spaces may be rendered more attractive, appealing and/or may affect the people working there positively if e.g. conference rooms, office rooms and/or cubicles have windows for letting in outside light and/or for providing a view to the outside environment. 
     In case it is not possible nor desirable to provide one or more real windows to e.g. an office space, home, or store, an installation of a virtual window device, or so called artificial window, may constitute an interesting alternative. Devices of this kind are configured to mimic an outdoor view, daylight, sunshine, or the like, in order to provide a realistic appearance of authentic windows. Typical examples of artificial daylight windows are artificial skylights. These skylights may have an optical architecture that is based on a focused beam of light that shines on a light-transmissive window that contains nanoparticles to scatter part of the blue light in the light beam. This creates a blue sky effect, and at the same time, a direct beam of artificial sunlight from the window. 
     In order to create a realistic skylight impression, a specific depth of the virtual window devices is required, since observers need to believe that there is a flat roof between the ceiling and the (simulated) sky view. Moreover, further development of virtual window devices is required to give the observer the impression of an authentic window. Hence, it is of interest to improve the properties of virtual window devices in order to augment the observer&#39;s impression of the authenticity of the window. 
     SUMMARY OF THE INVENTION 
     Hence, it is of interest to improve the properties of lighting devices in the form of artificial windows, and in particular lighting devices of these kinds which are intended for providing an outdoor view, sky light(s), or the like. 
     This and other objects are achieved by providing a virtual window device having the features in the independent claim. Preferred embodiments are defined in the dependent claims. 
     Hence, according to a first aspect of the present invention, there is provided a virtual window device, comprising a display arranged in a first plane, A. The display is arranged to provide a first output for rendering a first image of a view through a window onto a virtual planar surface that is oriented parallel to the display along an axis, C, perpendicular to the first plane, A. The virtual window device further comprises a frame, wherein the frame projects from the display, and wherein an edge of the frame, oppositely arranged the display, spans a second plane, B, parallel to the first plane, A. The virtual window device further comprises a lighting element configured to emit a second output onto the virtual planar surface, wherein the lighting element is arranged within the virtual window device at a distance, D, from the second plane, B, along the axis, C. The virtual window device further comprises a unit configured to control a directionality of the second output as a function of at least one content property of the first image. The term “content property of the first image” refers to a property of the visual content of the first image, and it may therefore also be referred to as a “visual content property”. 
     Thus, the present invention is based on the idea of providing a virtual window device for arrangement on (in) a wall or in a ceiling. The virtual window device is configured to provide a first output for rendering an impression to an observer of a first image of a view through a window, such as an outdoor view, a view of nature or an urban environment, a view of a sky, etc. The virtual window device is further configured to control a directionality of a second output, via a lighting element arranged within the virtual window device, as a function of one or more properties of the first image. Hence, the virtual window device is configured to render a dynamic light effect, by controlling the directionality of the second output, which matches the content property(ies) of the first image. 
     The present invention is advantageous in that the virtual window device may realistically achieve the effect of a view through a window, wherein the authenticity of the window view by the first image to an observer may be even further augmented by the directionality of the second output which is arranged to match the content(s) of the first image. Consequently, the virtual window device may render an authentic and/or realistic impression to an observer of being a ‘real’ window. 
     The present invention is further advantageous in that the lighting element, which provides the second output, may be arranged within the virtual window device such that it may not be visible for an observer, which may even further increase the authenticity of the virtual window device. More specifically, the lighting element may be ‘hidden’ from an observer positioned at an angle with respect to the virtual window device. The described arrangement of the lighting element within the virtual window device is particularly beneficial in case the virtual window device is configured to create an artificial daylight effect. 
     The present invention is further advantageous in that the versatility of the virtual window device, due to the various settings, configuration and/or design thereof, is able to achieve a realistic and/or authentic impression of a ‘real’ window. 
     The present invention is further advantageous in that the virtual window device may be provided with one or more display and lighting technologies such as LCD, OLED, QLED, microLED, etc. It will be appreciated that the numerous advantages of using LED technology may be provided in case LEDs are used as light source in the virtual window device. Compared to incandescent lamps, fluorescent lamps, neon tube lamps, etc., LEDs provide numerous advantages such as a longer operational life, a reduced power consumption, and an increased efficiency related to the ratio between light energy and heat energy. 
     The virtual window device of the present invention comprises a display arranged in a first plane. The first display part is arranged to provide a first output for rendering a first image of a view through a window. The first image of a view through a window may be an outdoor view, daylight, sunshine, or the like. The display is arranged to provide the first output onto a virtual planar surface that is oriented parallel to the display along an axis, perpendicular to the first plane. By “virtual planar surface”, it is here meant an imaginary surface or area in front of the virtual window device onto which the first output is projected. The virtual window device of the present invention further comprises a frame which projects from the display. An edge of the frame, oppositely arranged the display, spans a second plane, parallel to the first plane. The virtual window device further comprises a lighting element configured to emit a second output onto the virtual planar surface. By “lighting element”, it is here meant one or more lighting elements or light sources configured to emit light during operation. The lighting element is arranged within the virtual window device at a distance from the second plane along the axis. Hence, the lighting element is arranged within the virtual window device at a distance from the plane spanned by the edge of the frame, wherein the frame projects from the display. The virtual window device further comprises a unit configured to control a directionality of the second output as a function of at least one content property of the first image. By the term “directionality”, it is here meant one or more of (spatial) direction, beam angle, beam width, light output distribution, diffusivity, etc., of the second output. Hence, the unit is configured to control the directionality of the second output as a function of (dependently on) one or more properties of the first image. 
     According to an embodiment of the present invention, the lighting element may comprise at least a first light source arranged to emit light with a first directionality and a second light source arranged to emit light with a second directionality, different from the first directionality, wherein the unit is coupled to the lighting element and is configured to operate at least one of the first light source and the second light source in order to control the directionality of the second output. Hence, the virtual window device may comprise at least two different (sets of) light sources, wherein the unit is configured to operate one or more of these (sets of) light sources for controlling the directionality of the second output. The present embodiment is advantageous in that the authenticity of the window view by the first image to an observer may be even further augmented by the directionality of the second output via the individual control of the two or more light sources by the unit. For example, the first light source may be provided as a linear light array at one or more sides of the virtual window device. The first light source may provide a light output with a relatively high brightness. Furthermore, the virtual window device may comprise a second light source, wherein the second light source may constitute the backlight of the display. The second light source may be arranged to emit diffuse light with a relatively low brightness. 
     According to an embodiment of the present invention, the unit is configured to control the directionality of the second output so that the second output is provided onto a virtual cylindrical surface that is oriented perpendicular to the virtual planar surface. By “virtual cylindrical surface”, it is here meant an imaginary cylindrical surface or area in front of the virtual window device, onto which surface or area the second output is projected. Furthermore, by “cylindrical surface”, it should be noted that its base or cross section may take on substantially any form, such as a rectangular, square, circular form, or the like. 
     According to an embodiment of the present invention, the unit may be configured to control the directionality of the second output as a function of time. Hence, the unit of the virtual window device may be configured to control the directionality (e.g. spatial direction, beam angle, beam width, light output distribution, diffusivity, etc.) of the second output as a function of time. For example, the unit may be configured to control the directionality of the second output as a function of time according to a predetermined schedule or setting, e.g. in case the first image of a view through the window is a sunrise, daylight, sunset, or the like. Alternatively, the unit may be configured to control the directionality of the second output as a function of time according to the current first image of a view through the window, e.g. via sensors and/or analysis of the first image. The present embodiment is advantageous in that the authenticity of the virtual window device may be increased even further. 
     According to an embodiment of the present invention, the lighting element may be arranged in the first plane, adjacent the display. The lighting element may be arranged to emit the second output into an adjacent space or room of the virtual window device at angles which correspond to realistic angles of a sun beam. The present embodiment is advantageous in that the authenticity of the virtual window device may be increased even further whilst at the same time providing the lighting element in a position of the virtual window device in which it may be at least partially hidden from the view of an observer. 
     According to an embodiment of the present invention, the display may have a polygon shape, and the lighting element may be arranged at a corner of the display. For example, the display may be rectangular, and the lighting element may be arranged at a corner between the display and the frame. The present embodiment is advantageous in that the lighting element hereby may be provided relatively far away from the second plane, B, i.e. in a position of the virtual window device in which it may be at least partially hidden from the view of an observer. 
     According to an embodiment of the present invention, the lighting element may comprise a linear lighting element array arranged along an edge of the display. By “linear lighting element array”, it is here meant an array, arrangement or segment of lighting element(s) arranged linearly, such as linear arrays of LEDs, OLEDs, or the like. For example, in case the virtual window device comprises a rectangular display, each of the four sides of the display may be provided with a linear lighting element array. Each of these linear lighting element arrays may be controllable by the unit in order to control the directionality of the second output emitted by the lighting element as a function of at least one content property of the first image. Alternatively, or additionally, the linear lighting element array may comprise light sources which are individually controllable by the unit in their respective directionality. The present embodiment is advantageous in that the linear lighting element array may be conveniently controlled by the unit in order to provide a relatively high degree of authenticity of the virtual window device during operation. The present embodiment is further advantageous in that the linear lighting element array may be configured to illuminate one or more sides of the frame, which may render an aesthetically appealing effect. 
     According to an embodiment of the present invention, the lighting element may be arranged within the frame. Hence, the lighting element may be arranged inside the frame of the virtual window device. The present embodiment is advantageous in that the lighting element may emit the second output onto the virtual planar surface whilst at the same time being ‘hidden’ from an observer positioned at an angle with respect to the virtual window device. 
     According to an embodiment of the present invention, the lighting element may be arranged within a cavity of the display. For example, the display may comprise one or more holes in which the lighting element(s) may be arranged. The present embodiment is advantageous in that the first image may be rendered even more authentic to an observer. For example, in case of a first image of a view through a window of a sun in the sky, the unit of the virtual window device may be configured to control the directionality of the second output such that the virtual sun may always be present at a predefined position. 
     According to an embodiment of the present invention, the unit may be configured to register a content property of the first image and to control the second output as a function of the registered content property of the first image. Hence, the virtual window device may be configured to adapt the second output dependent on one or more content properties of the first image, e.g. by registering the content property(ies) via one or more sensors. The present embodiment is advantageous in that the virtual window device hereby may conveniently and efficiently adapt or control the second output with respect to the property(ies) of the image content of the first image in order to augment the authenticity of the virtual window device. 
     According to an embodiment of the present invention, the unit may be configured to register a property of the light in an environment of the virtual window device and to control the second output as a function of the registered property of the light. Hence, the virtual window device may be configured to adapt the second output dependent on one or more properties of the light in an environment or surrounding of the virtual window device. The present embodiment is advantageous in that the virtual window device may conveniently and efficiently adapt or control the second output in order to provide an even higher degree of authenticity of the virtual window device. 
     According to an embodiment of the present invention, the frame may comprise a light-emitting element, wherein the unit is coupled to the light-emitting element and is configured to control the light emitted from the light-emitting element as a function of at least one of the at least one content property of the first image, and the directionality of the second output. Hence, the unit is configured to control the light-emitting element as a function of the content property(ies) of the first image and/or the directionality of the second output. The present embodiment is advantageous in that the authenticity of the first image of the virtual window device may be even further increased if light emitted from the light-emitting element in and/or on the frame matches the content properties and/or conditions of the first output for rendering the first image of a view through a window. Therefore, in addition to the lighting element configured to emit the second output for creating the desired directional light effects during operation of the virtual window device, the frame may comprise light-emitting elements which are controlled by the unit as a function of the content property(ies) of the first image and/or the directionality of the second output. 
     According to an embodiment of the present invention, the unit may be configured to register a property of the light in an environment of the virtual window device and to control the light emitted from the light-emitting element as a function of the registered property of the light. Hence, the unit of the virtual window device may be configured to control and/or adapt the light emitted from the light-emitting element dependent on one or more properties of the light in an environment or surrounding of the virtual window device. The present embodiment is advantageous in that the virtual window device may conveniently and efficiently adapt or control the light emitted from the light-emitting element in order to provide an even higher degree of authenticity of the virtual window device. 
     According to an embodiment of the present invention, the frame may be rectangular and comprise four side portions, wherein the light-emitting element is arranged within the four side portions, and the unit is configured to control the light emitted from the light-emitting element in each side portion. 
     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 will realize that different features of the present invention can be combined to create embodiments other than those described in the following. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention. 
         FIGS.  1 - 2    schematically show perspective views of a virtual window device according to an exemplifying embodiment of the present invention, 
         FIGS.  3 ,  4     a - c  and  5  schematically show cross-sectional views of a virtual window device according to examples of the present invention, and 
         FIGS.  6   a,b    schematically show virtual window devices according to exemplifying embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    schematically shows a perspective view of a virtual window device  100  according to an exemplifying embodiment of the present invention. The virtual window device  100  comprises a display  110  arranged in a first plane, A. Here, the display  110  is exemplified as being rectangular. However, it should be noted that other shapes of the display  110  may be feasible. The virtual window device  100  further comprises a frame  150  which projects from the display  110 . In  FIG.  1   , the frame  150  projects perpendicular from the orientation of the display  110 , but it should be noted that the frame  150  alternatively may project obliquely from the orientation of the display  110 . An edge  160  of the frame  150 , which edge  160  is oppositely arranged the display  110 , spans a second plane, B, parallel to the first plane, A. 
       FIG.  2    schematically shows a perspective view of the virtual window device  100  according to  FIG.  1   . The display  110  is arranged to provide a first output  120  for rendering a first image of a view through a window  130 . The first image of a view through a window  130  may be an outdoor view, daylight, sunshine, or the like. The first image may comprise a nature setting or environment (e.g. clouds moving in the wind, trees, fields, etc.), an urban setting or environment (e.g. cars passing by), etc. For example, in case it is desired that the first image renders a skylight, the first output  120  may be configured to emit light within a wavelength range of 400-490 nm, representing blue or blue-like colors. The first image of a view through a window  130  may vary as a function of time, i.e. it may be (time) dynamic. For example, the first image of a view through a window  130  such as an outdoor view, daylight, skylight, sunshine, or the like, may vary as a function of time with respect to one or more properties, such as light intensity, light direction, color of the light, etc. The display  110  is arranged to provide the first output  120  onto a virtual planar surface  140  that is oriented parallel to the display  110 . The virtual planar surface  140  constitutes an imaginary surface or area in front of the virtual window device  100  along an axis, C, which is perpendicular to the first plane. 
       FIG.  3    schematically shows a cross-sectional view of the virtual window device  100  according to  FIG.  1    and/or  FIG.  2   . The virtual window device  100  is fitted into an aperture or cavity of a ceiling  125 . The display  110  of the virtual window device  100  is arranged in the first plane, A. The edge  160  of the frame  150 , oppositely arranged the display  110 , is arranged in the second plane, B, parallel to the first plane, A. Here, the second plane, B, is flush with the plane of the ceiling  125 . The virtual window device  100  further comprises a lighting element  170  configured to emit a second output  180  onto the virtual planar surface  140 . Here, the lighting element  170  is exemplified as two light sources, but it should be noted that the lighting elements  170  may alternatively comprise substantially any number of light sources, one or more (linear) arrays of lighting elements, etc. According to the example in  FIG.  3   , the lighting element  170  is arranged in the first plane, A, at a corner of the display  110  and the frame  150 . The lighting element  170  is arranged within the virtual window device  100  at a distance, D, from the second plane, B, along the axis, C. The distance, D, may be relatively large, such that the lighting element  170  which provides the second output  180  may not be visible for an observer. More specifically, the lighting element  170  may be ‘hidden’ from an observer positioned at an angle with respect to the virtual window device  100 . According to this example, D=|B−A| along the axis, C. 
     The virtual window device  100  as exemplified in  FIG.  3    further comprises a unit  190 . It should be noted that the unit  190  may be arranged within the virtual window device  100  or be (remotely) connected to the virtual window device  100 . The unit  190  may be connected to the lighting element  170  and may be configured to control a directionality of the second output  180  emitted from the lighting element  170  as a function of at least one content property of the first image rendered by the display  110  via the first output  120  on the virtual planar surface  140 . The directionality of the second output  180  may encompass one or more of (spatial) direction, beam angle, beam width, light output distribution, diffusivity, etc., of the second output  180 . The unit  190  is configured to control the directionality of the second output  180  as a function of (dependently on) one or more properties of the first image. For example, the unit  190  may be configured to control the direction of the second output  180  as a function of the direction of the first image as rendered by the first output  120 . More specifically, and according to an example, in case the display  110  is arranged to render a first image of a view through a window  130  mimicking a path of the sun in the sky, a sunrise and/or a sunset, the unit  190  may be configured to control the direction of the second output  180  as a function of the direction of this first image. For example, the unit  190  may be configured to control the shape, width and/or angle of the light of the second output  180  as a function of the properties of the beam of the light of the first output  120 . Via the control unit  190  of the virtual window device  100 , the lighting element  170  may render a beam shape of the second output  180  which matches the shape of the first output  120  of the display  110  for rendering the first image of a view through a window  130 . For example, the virtual window device  100  may comprise one or more optical elements (not shown) which may be arranged to create a rectangular beam shape of the second output  180 . 
     According to yet another example, the unit  190  of the virtual window device  100  may be configured to control one or more of the light output distribution, diffusivity, etc., of the second output  180  as a function of the direction of the first image. The virtual window device  100  may, via the unit  190 , be configured to vary a mimicked sunlight direction dependent on the time of day and/or time of year. The virtual window device  100  may further be configured to control the second output  180  dependent on e.g. real sunlight entering the room, and/or on other properties of the light in the room/area into which the virtual window device  100  is arranged to provide the first output  170  and second output  180 . 
     The registering of one or more properties of the first image and/or the light in an environment of the virtual window device  100  may be performed by registration means (not shown), for example, (a) light sensor(s), a camera, or the like. It will be appreciated that the registration means can be used to detect the current light properties and/or conditions outside the building where the virtual window device  100  is located. Alternatively, the registration means may comprise one or more indoor sensors, whereby the virtual window device  100  may adjust its second output dependent on the ambient light level in an environment of the virtual window device  100 . 
     In case the virtual window device  100  comprises one or more optical elements (not shown), these optical elements may provide various lighting distributions (e.g. directional distributions, diffusivity distributions, etc.) of the second output  180 . It will be appreciated that the virtual window device  100  hereby may mimic sunny vs. cloudy weather conditions with an even higher degree of authenticity to an observer. 
     According to yet another example, the unit  190  of the virtual window device  100  may be configured to control the directionality (e.g. spatial direction, beam angle, beam width, light output distribution, diffusivity, etc.) of the second output  180  as a function of time. For example, the unit  190  may be configured to control the directionality of the second output  180  as a function of time according to a predetermined schedule or setting, e.g. in case the first image of a view through the window  130  is a sunrise, daylight, sunset, or the like. Alternatively, the unit  190  may be configured to control the directionality of the second output  180  as a function of time according to the current first image of a view through the window  130 , e.g. via sensors and/or analysis of the first image. 
       FIGS.  4   a - c    schematically show cross-sectional views of virtual window devices  100  according to examples of the present invention. It will be appreciated that the virtual window devices of  FIGS.  4   a - c   , arranged in a aperture or cavity of a ceiling  125 , are similar to the virtual window devices of  FIGS.  1 - 3   , and it is referred to these figures and associated text for an increased understanding. In  FIG.  4   a   , the lighting element  170  configured to emit a second output  180  is arranged within the frame  150 . More specifically, the lighting element  170  is arranged within a cavity or slot of the frame  150 . Albeit the lighting element  170  is exemplified as two light sources, it should be noted that the lighting element  170  may alternatively comprise substantially any number of light sources, one or more (linear) arrays of lighting elements, etc. In  FIG.  4   b   , the unit (not shown) of the virtual window device  100  is configured to control the directionality (e.g. direction, beam angle, beam width, light output distribution, diffusivity, etc.,) of the second output  180  as a function of one or more properties of the first image rendered by the display  110  via the first output  120 . In  FIG.  4   c   , the lighting element  170  comprises a first light source  170   a  arranged to emit light with a first directionality, and a second light source  170   b  arranged to emit light with a second directionality, different from the first directionality. The unit (not shown) of the virtual window device  100  is coupled to the lighting element  170  is configured to operate at least one of the first light source  170   a  and the second light source  170   b  in order to control the directionality of the second output  180 . 
       FIG.  5    schematically shows a cross-sectional view of a virtual window device  100  according to an example of the present invention. The virtual window device of  FIG.  5    is similar to the virtual window devices of  FIGS.  1 - 4   , and it is referred to these figures and associated text for an increased understanding. The display  110  of the virtual window device provides a first output  120  for rendering a first image of a view through a window. The lighting element  170  is exemplified as eight light sources, but the lighting element  170  may comprise substantially any number of light sources, one or more (linear) arrays of lighting elements, etc. The lighting element  170  is arranged within the virtual lighting device  100  at a distance, D, from the second plane, B, along the axis, C, wherein D&lt;1B−A|. The lighting element  170   a  is arranged within a cavity or recess  175  of the frame  150 . By this arrangement of the lighting element  170   a  of the virtual window device  100 , the lighting element  170   a  may be invisible or ‘hidden’ for an observer  205  positioned at an angle with respect to the virtual window device  100 . For example, in case the cavity or recess  175  has an opening diameter, W, and an observer  205  is positioned at a distance, L, away from the artificial window device  100  (i.e. along the axis, C) and at a distance, K, along a direction parallel to the first plane, A, the distance D may be chosen such that D&gt;W·L/(2K). 
       FIGS.  6   a,b    schematically show virtual window devices  100  according to exemplifying embodiments of the present invention, and may represent a view from below (along the axis C) of the virtual window device  100  as exemplified in  FIG.  5   . In  FIG.  6   a   , the frame  150  is rectangular and comprises four side portions. The lighting element  170  is exemplified as a plurality of light sources, wherein each light source is arranged within a respective cavity or recess  175 . The light sources of each of the four sides of the frame  150  may constitute a linear lighting element array  172   a - d , and each of these linear lighting element arrays may be controllable by the unit in order to control the directionality of the second output emitted by the lighting element  170  as a function of at least one content property of the first image. For example, the unit may be configured to control a first pair  172   a  and  172   c  of the four linear lighting element arrays separately from the second pair  172   b  and  172   d  of the four linear lighting element arrays, due to their respective perpendicular orientation.  FIG.  6   b    shows a similar virtual window device  100  of that disclosed in  FIG.  6   a   , albeit the lighting element  170  is also provided in the center of the frame  150 . Hence, in addition to the four linear lighting element arrays arranged within the rectangular frame  150  as described in  FIG.  6   a   , the virtual window device  100  further comprises two linear lighting element arrays  172   e,f  arranged perpendicular to each other in the center of the virtual window device  100 . 
     The frame(s) of one or more of the virtual devices  100  as exemplified in  FIGS.  1 - 6    may furthermore comprise a light-emitting element, wherein the unit is coupled to the light-emitting element and is configured to control the light emitted from the light-emitting element as a function of at least one of the at least one content property of the first image, and the directionality of the second output. Furthermore, the unit may be configured to register a content property of the light in an environment of the virtual window device  100  and to control the light emitted from the light-emitting element as a function of the registered content property of the light. According to yet another example, the frame may be rectangular and comprise four side portions, wherein the light-emitting element is arranged within the four side portions, and the unit is configured to control the light emitted from the light-emitting element in each side portion. 
     The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, one or more of the virtual window device  100 , the display  110 , the frame  150 , etc., may have different shapes, dimensions and/or sizes than those depicted/described.