Optical display device

Abstract

An optical display device arranged to create a perception of a sky scene, comprising a collimated light source for generating a collimated light beam, a first optical expansion system, a second optical expansion system, a diffused light generation system, and an output aperture through which output light is projected, wherein the diffused light generation system is arranged to generate a diffused sky light component in the output light, the collimated light generation system is arranged to generate a collimated sunlight component in the output light, the first optical expansion system is arranged to expand the collimated light beam as the collimated sunlight component in a first expansion direction across the output aperture, and the second optical expansion system is arranged to expand the collimated light beam as the collimated sunlight component in a second expansion direction across the output aperture.

Description

Technical Field

[0001] The present disclosure generally relates to an electric optical display device for creating artificial skylight that enables an observer to experience the perception of a sky scene when looking into an output aperture of the device.

Background Art

[0002] Devices for creating the perception of skylight are provided in European Patent No. 3181999A. The device generates a collimated light beam from a light source and a collimator lens array. The collimated light beam is incident directly (e.g., without bending the light beam through a reflecting member) on a partially transparent diffusing light generator and passes through it. A part of the collimated beam is scattered by the diffusing light generator due to Rayleigh scattering as blue diffused light to provide an artificial skylight component, and a part of the collimated beam passes through the diffusing light generator to provide an artificial skylight component.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Such devices require a large light source array to achieve the intensity representing sunlight and must be precisely aligned between the light source and the individual collimator lens arrays, so they are costly and complex to manufacture. Furthermore, such devices can be complex to achieve a typical depth perception.

[0004] Therefore, despite the efforts hitherto devoted to the development of such devices, further improvements are desirable.

Means for Solving the Problems

[0005] The present disclosure provides an optical display device arranged to create a perception of a sky scene in the output light. The optical display device includes a collimated light generation system, a diffused light generation system, and an output aperture from which the output light is projected. The diffused light generation system is arranged to generate a diffused sky light (e.g., blue, purple, orange, or other colors of the sky) component in the output light. The collimated light generation system is arranged to generate a collimated sunlight (e.g., white and / or yellow) component in the output light, which may be observed as a sun-like disk projected at infinity. In embodiments, the collimated light generation system may include one or more of a collimated light source that may include a light source, and a collimating system / member arranged to collimate the light as a collimated light beam from the light source.

[0006] [Beam Expansion] In embodiments, the collimated light generation system includes a first optical expansion system and a second optical expansion system. The first optical expansion system is arranged to expand the collimated light beam in a first expansion direction across the output aperture to form a collimated sunlight component, and the second optical expansion system is arranged to expand the collimated light beam in a second expansion direction across the output aperture to form a collimated sunlight component. In embodiments, the second expansion direction is different from (e.g., non-collinear with) the first expansion direction.

[0007] By implementing a first optical expansion system that expands a collimated light beam (e.g., the beam after the collimating system) in a first direction as seen at the output aperture, and a second optical expansion system that expands the collimated beam in a second direction as seen at the output aperture, it is possible to expand one collimated light source while maintaining collimation at the output aperture. This may obviate the need to use multiple collimated light sources to cover separate sections of the output aperture.

[0008] As used herein, the term "expanded across the output aperture" means that a collimated light beam is expanded by various means upstream of the output aperture that have a net effect of expanding the collimated beam in a particular direction (e.g., perpendicular to the beam propagation direction) such that when the beam impinges on the output aperture, it covers a wider area of the output aperture. Thus, the expansion direction can be defined as the expansion length covered across the output aperture.

[0009] In an embodiment, the first optical expansion system is separated from the second optical expansion system. In an embodiment, the second optical expansion system is arranged to expand light after (e.g., downstream of and separate from) the first optical expansion system. By first expanding the collimated light beam in one direction and then, not simultaneously, in another direction, a controlled and precise expansion can be achieved.

[0010] In an embodiment, the first optical expansion system is arranged to generate a first expanded collimated light beam from the collimated light beam, and the second optical expansion system is arranged to generate a second expanded collimated light beam from the first expanded collimated light beam.

[0011] In an embodiment, and the first optical expansion system does not expand (including substantially not expanding) the collimated light beam in a second direction and / or the second optical expansion system does not expand (including substantially not expanding) the collimated light beam in a first expansion direction.

[0012] In an embodiment, the first and second optical expansion systems are arranged to effect a uniform expansion (e.g., an even expansion including substantially even) and / or a linear expansion (e.g., along only one line and not in other directions in their respective expansion directions) of the collimated light in the associated first and second expansion directions. By effecting a linear uniform expansion, the sunlight component of the output light can be uniform and thus can more realistically represent sunlight.

[0013] As used herein, the term "uniform" may mean a uniform property of light in one or more respects, such as color, intensity, collimation, power, or other related properties perceptible to an observer.

[0014] In embodiments, the average divergence angle of the expanded collimated light beam (e.g., from one or both of the beam expansion systems) is within 10% of the divergence angle of the collimated light beam, or 5% or 2.5%. In such implementations, the optical expansion system may hold the appropriately collimated light while expanding the beam.

[0015] In embodiments, the first and / or second optical expansion systems are configured to expand the collimated light beam at least 2, 3, 5, or 10 times in the first and second directions, respectively, with an optional maximum of 20 - 30 times. Such implementations may expand one collimated light beam to cover most of the output aperture.

[0016] In embodiments, the collimated light beam is expanded in at least one of the directions to the extent (including substantially to the extent) of the output aperture in that direction. With such a configuration, a single light source may cover all of the output aperture in at least one direction, thereby obviating the need for many light sources.

[0017] In embodiments, the first and second expansion directions are orthogonal to each other / across the output aperture. In embodiments, the output aperture extends in a lengthwise and a transverse direction, the first direction is aligned with the transverse direction, and the second direction is aligned with the lengthwise direction. Such a configuration may cover the entire output aperture using two optical expansion systems.

[0018] In an embodiment, the first optical expansion system includes a prism sheet arranged obliquely in the propagation direction of the incident collimated light beam and expanding the collimated light beam into a first expanded collimated light beam. By configuring the collimated light beam to be projected obliquely onto the first prism sheet, the beam is incident over the length of the prism sheet that is greater than the width of the beam. Thus, by selecting a specific tilt angle (e.g., 2 to 30 or 5 to 20 degrees), a large expansion angle can be achieved. The prism sheet can expand the beam by reflection or by reflection and refraction.

[0019] In an embodiment, the prism sheet is arranged such that the collimated light beam either passes through it or is reflected therefrom. In an embodiment, the prism sheet is arranged obliquely with respect to the inclined aperture.

[0020] In an embodiment, the second optical expansion system is arranged obliquely in the propagation direction of the incident first expanded collimated light beam and expanding the first collimated light beam into a second expanded collimated light beam. In an embodiment, the first prism sheet is oblique with respect to the second prism sheet. By arranging the collimated light beam to be projected obliquely onto the second prism sheet, the beam is incident over the length of the prism sheet that is greater than the width of the beam. Thus, by selecting a specific tilt angle (e.g., 3 to 30 or 5 to 20 degrees), a greater expansion factor can be achieved. The prism sheet can expand the beam by reflection or by reflection and refraction.

[0021] In an embodiment, the second prism sheet is arranged to cover the output aperture and can be flat with respect thereto, and can project the second expanded collimated light beam as a collimated sunlight component through the output aperture. By arranging the second prism sheet to overlap the output aperture (e.g., when viewed in a direction perpendicular to the plane of the output aperture) and preferably aligned within the same plane as the output aperture, the device can be made smaller and / or more convenient for assembly.

[0022] In an embodiment, the collimated light source includes a light source and a collimation system that receives light from the light source and generates a collimated light beam therefrom, and the collimation system is an off-axis parabolic reflector. The off-axis parabolic reflector can provide a cost-effective collimation system.

[0023] In an embodiment, the light source is projected onto the collimation system via a coupling system. The coupling system can provide a convenient expansion of the light beam from the light source before it is collimated by the collimation system. The coupling system can include one or more of a prism, a light pipe, and a lens (e.g., a convex lens).

[0024] In an embodiment, the collimated light source (including one or more of the light source, the coupling system, and the collimation system) is arranged (e.g., by a field angle-dependent member and / or a positional arrangement) so as not to interfere with the light projected from the collimation system and a certain one of its or its first prism sheet.

[0025] [Field control] In an embodiment, the field angle control system is arranged to obscure at least a part of the collimated light generation system and / or the diffused light generation system when viewed through the output aperture.

[0026] By arranging the field angle control system to completely or partially reduce the visibility of the collimated light generation system (e.g., one or more of the light source, the collimation system, and the mounting components for the components) and / or the diffused light generation system (e.g., the light source and / or the diffuser) (with respect to the conditions of the omitted field angle control system), a more realistic appearance of the sky scene is provided, which in turn lacks visual cues.

[0027] In an embodiment, the field of view control system at least partially overlaps with the output aperture. By arranging the field of view control system to overlap with the output aperture (e.g., the output aperture is aligned with the plane defined by the horizontal and length directions, and the overlap is observed when looking along the normal to the plane), the field of view control system can conveniently obscure the component.

[0028] In an embodiment, the field of view control system includes a field of view dependent member, which is configured to be optically transparent (substantially optically transparent) from a first field of view range and optically opaque (substantially optically opaque) from a second different field of view range.

[0029] By implementing a member having variable opacity based on the field of view (the opacity may include blurring), the member can be arranged to eliminate / reduce the visibility of the aforementioned components of the device (e.g., one or more of the light source, collimating member, and prism sheet) at a specific field of view with respect to the output aperture, for example, at a high incident angle (e.g., exceeding 60, 70, 80, or 85 degrees), and the member can become opaque.

[0030] In an embodiment, the field of view control system includes a reflector system, which is arranged to reflect light from the light source (e.g., collimated light and / or pre - collimated light) around the light source and / or the collimating system and / or the prism sheet of the first optical expansion system.

[0031] By implementing the reflector system to reflect light around the collimated light source / prism sheet (e.g., such that the reflected light overlaps with the collimated light source / prism sheet when viewed from the plane defined by the horizontal and length directions), the visibility of the collimated light source / prism sheet from the output aperture can be reduced.

[0032] In an embodiment, the reflector system includes one or more reflecting members arranged to reflect collimated light from a collimating system in opposite directions (including substantially opposite directions) at different depths (including substantially different depths). By mounting the reflector system to reflect the collimated light at a depth in the longitudinal direction opposite to the projection across the collimated light source so that it is between the collimated light source and the output aperture, the visibility of the collimated light source from the output aperture can be reduced.

[0033] In an embodiment, the reflector system includes a shelf member disposed in the line of sight between the output aperture and the collimated light source (e.g., the light source and / or the collimating system) since it is visible from a predetermined viewing angle.

[0034] In an embodiment, the shelf member is arranged to have a diffusely reflecting outer surface and may be white. In an embodiment, the shelf member is arranged so that the collimated light source is not visible from a predetermined viewing angle. In an embodiment, the light source is arranged so as not to overlap the output aperture.

[0035] [Beam Estimation] In an embodiment, the collimated light generation system includes a first collimated light source and a second collimated light source, and the collimated light generation system is arranged such that the first and second collimated lights are projected from the first collimated light source and the second collimated light source through the output aperture, respectively.

[0036] In an embodiment, the first and second collimated light beams overlap each other. In an embodiment, the first and second collimated light beams overlap each other so as to have a common central axis (including substantially common). The overlapping collimated light beams are projected as a collimated sunlight component through the output aperture.

[0037] By implementing first and second collimated light sources that each project collimated light beams that overlap with each other and have the same common central axis, the intensities of both beams can be superimposed to produce a beam with a higher intensity than can be achieved with a single light source, which can better represent sunlight. Further, the color components of the overlapping parallel beams can be conveniently controlled by varying the ratio of the light from each collimated light source, for example, to provide more yellow or white sunlight components.

[0038] As used herein, the term "central axis" can mean the axis along which the center point of a beam of collimated light is projected from one of the collimated light sources outwards. As used herein, the term "common" with respect to the central axis can mean axes that are precisely aligned or are aligned sufficiently to provide the appearance of one sunlight beam with a uniform intensity, for example, across the beam projection area.

[0039] In an embodiment, the first collimated light source can include a light source and a collimating system, and the second collimated light source can include a light source and a collimating system. Alternatively, the first and second collimated light sources can include separate beams obtained from a common single light source and / or collimating system.

[0040] In an embodiment, the first and second light beams are uniform (including substantially uniform). By implementing the first and second light beams to be uniform (e.g., through an output aperture), precise alignment of their central axes may not be required. In an embodiment, the first and second light beams are sufficiently overlapped with each other, for example, such that at least one sufficiently overlaps the other and both sufficiently overlap each other at the output aperture.

[0041] In an embodiment, the collimated light generation system includes a mixing element, which is arranged to superimpose light beams from a first collimated light source and a second collimated light source. The mixing element can be arranged to superimpose the light beams from the first collimated light source and the second collimated light source so as to have the common central axis. The mixing element can project the collimated sunlight component / superimposed collimated light beam onto the output aperture. By mounting a mixing element, for example, a prism sheet, the light beams can be conveniently superimposed vertically.

[0042] In an embodiment, the light beam from the first collimated light source and the light beam from the second collimated light source are projected onto the mixing element in different directions. The different directions can be opposite in the lateral and / or longitudinal components of the directions. By projecting the light beams onto the mixing element from different directions, they can be conveniently combined.

[0043] In an embodiment, the light beam from the first collimated light source and the light beam from the second collimated light source are projected onto the mixing element so as to have its central axis (including substantially up to) to a common intersection point. By arranging the light beams to intersect at a common (including substantially common) center point that can be on or in the mixing element, they can be conveniently combined.

[0044] In an embodiment, the superimposed collimated light beam is projected so that its central axis intersects (including substantially intersects) the center of the output aperture. As used herein, the term "center" with respect to the output aperture means exactly at the center of the output aperture or substantially at its center when considering the plane defined by the longitudinal and lateral directions, and can mean, for example, deviating by 95% or less, or 90% or less of the longitudinal length or lateral width of the output aperture.

[0045] In an embodiment, the overlapping collimated light covers the entire output aperture. By arranging the beam to be projected through the entire output aperture, a realistic simulation of sunlight can be provided. As used herein, the term "entire" with respect to the output aperture can mean, for example, complete coverage of the surface area defined in the length and width directions, such as 100%, or substantially complete coverage, such as at least 95%.

[0046] In an embodiment, the hybrid element includes a prism sheet. In an embodiment, the prism sheets may be arranged to overlap and be in the same plane as the output aperture. By arranging the prism sheets in a plane defined by the length and width directions, for example, substantially or completely overlapping and in the same plane, including being substantially in the same plane, the device can be convenient for assembly and can be made smaller.

[0047] In an embodiment, the prism sheet is arranged substantially in the depth and width directions and may be inclined in the depth direction.

[0048] In an embodiment, the prism sheet is arranged to redirect the collimated light beam and project the overlapping collimated light beam onto the output aperture.

[0049] In an embodiment, the prism sheet includes symmetric prism projection. The prism projection can be symmetric around a symmetry axis perpendicular to the incident directions of the first and second collimated light beams.

[0050] In an embodiment, the light source of the first collimated light source is controllable independently of the light source of the second collimated light source. By implementing the light sources to be controllable independently, the electrical circuit can control the intensity of any of the light sources to change the ratio of the parallel sunlight component from any of the light sources. In an embodiment, the first collimated light source and the second collimated light source have different colors (e.g., CCT or other output models), and thus the color of the parallel sunlight component can be controlled by controlling the intensity of the light sources.

[0051] Similarly, the light source of the diffused light generation system can be controllable independently of the first collimated light source and / or the second collimated light source (if the latter exists). With such an arrangement, it may be possible to control the ratio of the diffused skylight component and the ratio of the parallel sunlight component in the output light.

[0052] [Non-overlapping beams] In an embodiment, the collimated light generation system is arranged such that the first and second collimated light sources projected through the output aperture from the first collimated light source and the second collimated light source are coupled to each other, laterally aligned, and have an offset central axis in the longitudinal direction.

[0053] By implementing such that the first and second beams are coupled to each other through the output aperture, and are projected such that they are laterally aligned, have an offset central axis in the longitudinal direction, they can advantageously have individually controllable portions while covering the entire output aperture. As used herein, the term "coupled" with respect to an optical beam can mean an optical beam whose edges are aligned completely or substantially (e.g., such that the overlap or gap between adjacent edges is minimized).

[0054] In an embodiment, the collimated light generation system includes a projection element, which is arranged such that a first portion receives the first collimated light beam and directs the beam towards the output aperture, and a second portion receives the second collimated light and directs the beam towards the output aperture (e.g., thereby directing both beams towards the output aperture in the same direction). The projection element can be implemented as a prism sheet, and the prism of the first portion is configured differently from the second portion so as to handle different projection directions of the first and second parallel beams.

[0055] In an embodiment, the light beam from the first collimated light source and the light beam from the second collimated light source are projected onto the projection element in different directions. In an embodiment, the projection element is arranged to direct the first and second parallel beams so as to cover the entire output aperture.

[0056] [Oblique Projection] In an embodiment, the collimated light generation system includes a reflecting member, the output aperture has a peripheral portion extending in a first plane defined by a lateral direction and a longitudinal direction, and the reflecting member is arranged to project light obliquely and inclined in both the lateral direction and the longitudinal direction across the entire first plane.

[0057] By implementing such that the light is projected obliquely, for example, in a diagonal direction, so as to overlap across the output aperture (or within the plane in which the output aperture exists), the optical path traveled by the light of the collimated light generation system can be conveniently bent and the distance can be maximized, which can improve the visual appearance of sunlight at infinity.

[0058] In an embodiment, the reflecting member is positioned to at least partially overlap the output aperture. By arranging the reflecting member to cover the output aperture, the form factor of the device can be reduced. Further, it may thereby be possible to arrange the device such that there is no substantial gap between adjacent output apertures of the device.

[0059] In an embodiment, the reflecting member is an off-axis parabolic reflector arranged to reflect light as collimated light. Such an arrangement can provide a cost-effective collimation configuration.

[0060] In an embodiment, the reflecting member is inclined with respect to both a first plane and a second plane defined by a depth direction and a longitudinal direction and / or a plane defined by a depth direction and a lateral direction.

[0061] In an embodiment, the pre-collimated light from the light source is obliquely projected across a first plane. By arranging the light source to project obliquely (e.g., in a diagonal direction) across the output aperture (or within the plane in which the output aperture lies), the optical path traversed by the light of the collimated light generation system can be conveniently bent to maximize the distance, which can improve the visual appearance of the sunlight component at infinity.

[0062] In an embodiment, the coupling system (e.g., a prism) is arranged to transmit the pre-collimated light from the light source to the reflecting member (e.g., directly). In an embodiment, the pre-collimated light is obliquely projected across a first plane. By arranging the coupling system to project light obliquely across the output aperture (or within the plane in which the output aperture lies), the optical path traversed by the light from the collimated light generation system can be conveniently bent to maximize the distance, which can improve the visual appearance of the sunlight component at infinity.

[0063] In an embodiment, the coupling system is positioned so as to at least partially overlap with the output aperture. By arranging the coupling system to cover the output aperture, the form factor of the device can be reduced.

[0064] In an embodiment, the light source is positioned so as to at least partially overlap with the output aperture. By arranging the light source to cover the output aperture, the form factor of the device can be reduced.

[0065] In an embodiment, the collimated light generation system includes a first prism sheet arranged to project the re-directed collimated light from the reflecting member onto the output aperture, and the reflecting member projects the collimated light onto the first prism sheet (e.g., directly). In an embodiment, and the first prism sheet is arranged to re-direct the collimated light again by reflection and / or refraction. The first prism sheet can be inclined in the depth direction.

[0066] In an embodiment, the collimated light generation system includes a second prism sheet arranged to receive collimated light from a first prism sheet (e.g., directly or via a reflecting member), and the second prism sheet is arranged in a first plane. In an embodiment, the second prism sheet is arranged to redirect the collimated light by reflection and / or refraction. In an embodiment, the diffused light generator is arranged in the first plane.

[0067] [Off-axis collimator] In an embodiment, the collimated light generation system includes an off-axis reflecting member arranged to receive light from a light source and project collimated light as a sunlight component to an output aperture.

[0068] By implementing an off-axis reflecting member as the collimation system, the light beam can be conveniently bent and collimated. By bending the light beam, the distance between the light source and the output aperture can be increased, which can enhance the perception of the light source at infinity. By bending the light beam, for a certain distance between the light source and the output aperture, it may be possible to arrange the optical display device with a smaller form factor.

[0069] In an embodiment, the off-axis reflecting member has a reflecting surface on a flat rear surface, and the rear surface is arranged such that an edge is aligned with one or more of the length, width, and depth directions of the device (including being substantially aligned at a small inclination angle, e.g., 0 to 20 degrees).

[0070] In an embodiment, the off-axis reflecting member is arranged such that at least one edge is parallel (including substantially parallel) to one or more of the width, length, and depth directions. By making at least one edge parallel to said direction, the device can be conveniently assembled.

[0071] [Projection over the entire output aperture] In an embodiment, the collimated light generation system includes a single light source (which may be the only light source of the collimated light generation system) and a collimation system (which may be the only collimation system of the collimated light generation system), the output aperture extends rectangularly in the lateral and longitudinal directions, and the collimated light generation system is arranged to project collimated light from the single light source across the entire output aperture.

[0072] By implementing the collimated light generation system to project the collimated sunlight component across the entire output aperture using the light expanded from a single light source, a cost-effective device can be provided, which can be conveniently assembled. Further, the device can have high accuracy because there is no problem related to integrating light from different light sources into the collimated sunlight component.

[0073] In an embodiment, the collimated light generation system is arranged to internally reflect the collimated light beam at least once, twice, or three times before it is output as the collimated sunlight component. The maximum number of reflections can be four, five, or six. By internally reflecting the collimated light beam, the optical path from the light source to the output aperture becomes longer, which can improve the appearance of the aspect at infinity.

[0074] In an embodiment, the single light source can implement the first optical expansion system and / or the second optical expansion system, and all functions associated therewith. The single light source and the collimation system can be implemented as the first collimated light source (for example, there is no second collimated light source), and all functions associated therewith.

[0075] [Usage / Component Kit] The present disclosure provides a component kit assembled in an optical display device of any of the above-described embodiments or other embodiments disclosed in this specification.

[0076] The present disclosure provides for the use of a device of any of the above-described embodiments or other embodiments described herein for creating a perception of a sky scene.

[0077] [Method] The present disclosure provides a method for creating a perception of a sky scene.

[0078] In an embodiment, the method includes expanding light from a collimated light beam in a first direction as viewed through an output aperture, expanding light from the collimated light beam in a second direction as viewed through the output aperture, and outputting the expanded collimated light as a collimated sunlight component.

[0079] In an embodiment, the method includes obscuring at least a portion of a collimated light generation system as viewed through an output aperture by a field of view control system. In an embodiment, the method includes obscuring at least a portion of a diffused light generation system as viewed through the output aperture by the field of view control system.

[0080] In an embodiment, the method includes projecting collimated light beams from a first collimated light source and a second collimated light source as a superimposed collimated light beam around a common central axis, and outputting the superimposed collimated light beam as a collimated sunlight component.

[0081] In an embodiment, the method includes projecting collimated light from a single light source across an entire output aperture.

[0082] In an embodiment, the method includes projecting collimated light beams from a first collimated light source, a second collimated light source, and a light source through an output aperture, the beams being coupled to each other, arranged to be laterally aligned, and having a longitudinal direction and an offset central axis.

[0083] In an embodiment, the method includes transmitting collimated light obliquely across an output aperture and outputting the collimated light as a collimated sunlight component through the output aperture.

[0084] In an embodiment, the method includes outputting diffused light as a diffused skylight component. In an embodiment, the method includes transmitting light through a diffused light generator to generate diffused light.

[0085] The method may implement any of the functions of any of the preceding embodiments or other embodiments disclosed herein.

[0086] The above summary is provided for the purpose of summarizing some embodiments in order to provide a basic understanding of aspects of the subject matter described herein. Accordingly, the foregoing features are merely examples and should not be construed as narrowing in any way the scope or gist of the subject matter described herein. Further, the above and / or preceding embodiments may be combined in any suitable combination to provide yet another embodiment. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following "Detailed Description of Embodiments", the drawings, and the claims.

[0087] Aspects, features, and advantages of embodiments of the present disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings, in which like numerals refer to like elements.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0089] Before describing some embodiments of the device, it should be understood that the device is not limited to the details of the construction or processes described in the following description. It will be apparent to those skilled in the art who enjoy the benefits of this disclosure that the device can take other embodiments and can be practiced or carried out in various ways.

[0090] This disclosure can be better understood by reading the following description.

[0091] As used herein, the term "optical display device" or "device" can mean an electro-optical device capable of providing an observer with a perception of the sky scene when looking into the output aperture of the device. The device can be sized to be suitable for mounting on the ceiling or wall of a room or building, for example, it is less than 1.5 meters or 2 meters or 3 meters in the lateral and / or longitudinal dimensions.

[0092] As used herein, the term "perception of infinite depth" may mean the depth of an object (such as the sky and / or the sun) perceived as infinitely far away from an observer performing stereoscopic vision (i.e., binocular vision). The perception of infinite depth may be provided by one or more of the following monocular or binocular visual cues presented to the observer when peering into the output aperture of the device, namely motion parallax, occlusion factors, atmospheric perspective, accommodation, binocular vision, convergence, and other related cues. The state of infinite depth may be identified based on the observer's eye line-of-sight vector having the same and / or similar alignment when peering into the device as when actually looking at the sky and / or the sun. The state of infinite depth based on motion parallax may be identified based on an image of the sun that appears to be moving, for example, projected from the same position as the observer moves laterally and / or longitudinally across the output aperture. The user, who is the observer, may maintain the same line-of-sight vector associated with the infinite depth during the movement.

[0093] As used herein, the term "perception of sky scene" may mean that an observer perceives as existing in the real world based on the construction by a device of a virtual sky scene that is sufficiently representative to present the sky scene to the observer, for example, in terms of the color and spatial distribution of light.

[0094] As used herein, the term "sky scene" may mean a scene including the sky as observed when an observer looks through a window of a structure (such as a sidewall or ceiling). The sky scene may include a skylight component and a sunlight component as defined herein. This may include a circular (including substantially circular) colored image of the sun as the sunlight component, which is surrounded by the blue sky (or other color representing the sky) as the skylight component.

[0095] As used herein, the terms "skylight" or "skylight component" or "diffuse light component" can mean artificial light that can include skylight, such as at sunset or sunrise (e.g., without a direct sunlight component). This can represent skylight in terms of, for example, a color (e.g., 5000 - 10000) defined by CCT, diffusivity, luminance profile or intensity, other suitable parameters, and one or more points of deviation of any of the above across the output aperture of the device. The diffuse light component can be uniform, which does not vary by more than 10%, 20%, 30% or 40% across the entire output aperture in terms of, for example, one or more of color diffusivity, luminance profile, intensity, and other suitable parameters. More specifically, the one or more parameters can be uniform to the extent that they do not vary by more than 10%, 20%, 30% or 40% for any circular region on the 10 mm diameter output aperture covering at least 90% of the output aperture. In a particular example, the diffuse light propagates over an HWHM solid angle that is at least 4 times larger or 9 times larger or 16 times larger than the corresponding sunlight's HWHM solid angle, measured in units of Sr.

[0096] As used herein, the terms "sunlight" or "sunlight component" or "direct light component" can mean artificial light that represents sunlight. This can represent sunlight in terms of, for example, a color (e.g., 3000 - 5000k lower than that of the skylight component) defined by CCT, divergence (e.g., the divergence angle of the light rays can be 5 degrees, 2 degrees, 1 degree or 0.5 degrees or less), luminance profile or intensity, other suitable parameters, and one or more points of deviation of any of the above across the output aperture of the device. In a particular example, the luminance profile of the sunlight can have a narrow peak within the angular distribution around the propagation direction facing an HWHM solid angle smaller than 0.2 sr or 0.3 s. The sunlight component can be projected uniformly across the output aperture, such that the average propagation direction within a 10 mm diameter circle at any position across the output aperture does not vary by more than 2%, 5%, or 10%. Sunlight can exist for the user as a circular disk positioned at infinity when looking into the device.

[0097] As used herein, the term "collimated light" may mean light that can form a sunlight component and is processed by a collimated light generation system.

[0098] As used herein, the term "output aperture" may mean the viewing window of a device through which an observer can look in. The output aperture can be 0.5 - 2 m × 0.5 - 2 m. The output aperture outputs the output light generated by the device. The output aperture can be defined by a transparent panel, which can include glass or plastic, or may not include such a member. For example, instead of such a member, it can include a void.

[0099] As used herein, the term "reflective member" may mean an object that can reflect an image by specular reflection. This can include any member having a surface whose texture or roughness is smaller than the wavelength of the incident light (smooth). This can include a surface formed of one or more of the following reflective materials, namely metals, metal oxides, and dielectric materials. Examples thereof include titanium oxide-based materials containing silver, aluminum, titanium dioxide, or titanium trioxide. Any of the above can be deposited as a thin coating on a glass carrier.

[0100] As used herein, the term "reflective member" may mean an object that can reflect an image by specular reflection. This can include any member having a surface whose texture or roughness is smaller than the wavelength of the incident light (smooth). This can include a surface formed of one or more of the following reflective materials, namely metals, metal oxides, and dielectric materials. Examples thereof include titanium oxide-based materials containing silver, aluminum, titanium dioxide, or titanium trioxide. Any of the above can be deposited as a thin coating on a glass carrier.

[0101] As used herein, the term "diffuse light generator" or "diffusion generating system" can mean a single (e.g., a collimating member) or distributed system that can generate a diffuse light component, e.g., light scattered at multiple angles with respect to one angle in the case of specular reflection. The diffuse light generator can generate diffuse light by reflecting the incident light as diffuse light, or can be at least partially transparent and generate diffuse light in the light transmitted therethrough, e.g., by particles floating in a transparent material. The diffuse light generator can be implemented as one or more of the following, namely, particles that scatter light, conical microcones, microlenses, quantum dots, surface features including surface etching, and other suitable implementations.

[0102] As used herein, the term "scattering the light" can mean the process performed on the incident light by a diffuse light generator to generate diffuse light, and can include Rayleigh scattering.

[0103] As used herein, the term "particles that scatter the light" can mean particles of a selected diameter for scattering some or all wavelengths of visible light. The diameter of the particles can be at the micro or nano level (for operating in the Rayleigh process). The diffuse light generator can include the particles disposed in a medium. Examples thereof include titanium dioxide suspended in PMMA.

[0104] As used herein, the term "light guide panel" can mean a generally flat member arranged to transmit light in a plane direction as a waveguide, e.g., by total internal reflection. The light guide panel can be, for example, of an edge-lit type by a light source. The light guide panel can be implemented as a diffuse light generator, e.g., particles in the light guide panel scatter light so that it exits the waveguide.

[0105] As used herein, the term "light source" may mean any device capable of generating artificial light. This can include devices that convert an electric current into light emission. The wavelength of the light can be in the range of 400 to 700 nm. The light source can include, among others, a white light source, or one that is so perceived by the eye, such as an incandescent lamp, a fluorescent lamp, a mercury vapor discharge lamp, an LED, or a white light laser diode (i.e., where the primary light source is combined with one type of phosphor or several types of phosphors), or a combination of LEDs or laser diodes of different colors, and one or more of other suitable light sources. The light source can include a light guide that receives light from the light emitting portion and transmits this light to the output surface, for example, by total internal reflection. The light source can be arranged to emit light at a CCT of 3K to 20K or along the daylight locus. The luminance profile may not vary by more than 20% in any circular region with a diameter of 10 mm.

[0106] As used herein, the term "color system" may mean a device capable of imparting a specific color to light from a light source, for example. The color can represent a sky scene including daylight, sunset, or sunrise. This can include, for example, a filter. The color system can be applied to skylight or sunlight components.

[0107] As used herein, the term "collimated light generation system" may mean a single or distributed (e.g., multiple) collimated light source for generating a collimated beam. This can include a collimating member / system, which can be implemented as one or more of the following, namely a lens including a Fresnel lens, a parabolic reflector, a closed cell structure through which light is projected, and other suitable systems. The collimated light generation system can include a light source (e.g., a dedicated or general-purpose light source for collimated light) for outputting light that is to be collimated by the collimating member. If the light source is a laser or other light source having a suitable collimated output, the collimating member can be omitted. The collimating system can consist of only one collimating member and an optional single light source.

[0108] As used herein, the term "prism sheet" may mean an arrangement of prisms on a flat member, which retains the initial collimation degree of an incident light beam but expands the beam. The expansion may be achieved by reflection or reflection and / or refraction. An example of such an arrangement is disclosed in WO 2017 / 048569.

[0109] As used herein, the term "electrical circuit configuration" or "circuit configuration" or "control charge circuit configuration" may mean one or more hardware and / or software components, examples of which include application specific integrated circuits (ASICs), electronic / electrical components (which may include transistors, resistors, capacitors, inductors, etc.), one or more processors, non-transitory memories (e.g., implemented by one or more memory devices) capable of storing one or more software or firmware programs, combinational logic circuits, and interconnections thereof. The electrical circuit configuration may be located entirely on a device or may be distributed among one or more of a device, an external device, and a server system.

[0110] As used herein, the term "processor" or "processing resource" may mean one or more units for processing, examples of which include ASICs, microcontrollers, FPGAs, microprocessors, digital signal processors (DSPs), state machines, or other suitable components. A processor may be configured to execute a computer program, which may be in the form of, for example, machine-readable instructions and stored on non-transitory memory and / or programmable logic. A processor may have various arrangements corresponding to those described for its circuit configuration. As used herein, any apparatus-executable instructions or computer-readable media may be configured such that the disclosed methods may be executed, for example, by the devices or systems described herein, and thus, the term "method" and, as synonyms, or interchangeably, may be used.

[0111] As used herein, the terms "communication resource" or "communication interface" mean the hardware and / or firmware for electronic information transmission. The communication resource / interface may be configured for wired communication ("wired" communication resource / interface) or wireless communication ("wireless" communication resource / interface). The wireless communication resource may include hardware for wirelessly transmitting and receiving signals and may include various protocol implementations, such as the 802.11 standard described in the Institute of Electronics Engineers (IEEE) and Bluetooth (trademark) of the Bluetooth Special Interest Group in Kirkland Wash. The wired communication resource may include Universal Serial Bus (USB), High-Definition Multimedia Interface (DHMI), or other protocol implementations. The device may include a communication resource for wired or wireless communication with an external device and / or a server system.

[0112] As used herein, the terms "external device" or "external electronic device" or "peripheral device" may include electronic components external to the device, such as those that communicate with the device in a computer network, those located in the same location as the machine, or those located at a location remote from the device. The external device may include a communication interface for communicating with the machine and / or a server system. The external device may include devices including smartphones, PDAs, video game controllers, tablets, laptops, or other similar devices.

[0113] [General System] Referring to FIG. 1, a device 2 that attempts to create a perception of a sky scene in the output light includes a collimated light generation system 4, a diffused light generation system 6, and an output aperture 8 through which the output light 10 is projected. The collimated light generation system 4 generates a collimated sunlight component 12 in the output light 10. The diffused light generation system 6 generates a diffused sky light component 14 in the output light 10.

[0114] In a modified embodiment not shown, the diffused light generation system is omitted, and for example, the sky scene contains only sunlight.

[0115] [First Embodiment] Referring to FIGS. 2, 3, and 4, a first embodiment of the apparatus 2 includes a collimated light generation system 4 having a first collimated light source 16. The first collimated light source 16 includes a light source 18 and a collimation system 20. The light source 18 projects a light beam 22 onto the collimation system 20, which processes the received light and outputs a collimated light beam 24, which forms the collimated sunlight component 12 in the output light 10.

[0116] In a modified embodiment not shown, the collimated light generation system includes a plurality of collimated light sources and / or collimation systems.

[0117] As best seen in FIGS. 3 and 4, the diffused light generation system 6 includes a diffuser 26 arranged as a waveguide through which the collimated sunlight component 12 is projected. The diffused light generation system 6 includes a dedicated diffused light source 28, which emits light towards the edge of the diffuser 26. The diffuser 26 includes particles (not shown) that scatter the internally reflected light from the light source 28. The light emitted from the light source 28 is retained within the diffuser 26 by total internal reflection, and finally it can encounter the particles and be scattered, exiting the diffuser 26 as the diffused sky light component 14. The portion of the collimated sunlight component 12 that encounters the particles can also be scattered in this way.

[0118] In a modified embodiment not shown, the diffused light generation system can omit the dedicated diffused light source, and the diffused sky light component is provided by the portion of the collimated light scattered by a transparent member. The diffuser can alternatively be arranged, for example, it can form an output aperture. Other diffused light generation systems are also conceivable.

[0119] The output aperture 8 is flat and is aligned in the length direction 100 and the width direction 102. The thickness of the device 2 is arranged in the depth direction 104. The housing 30 that houses the components of the device 2 described in this specification extends in the length direction 100, the width direction 102, and the depth direction 104.

[0120] The collimating system 20 of the collimated light generation system 4 includes an off-axis parabolic reflector 32, which receives the light beam 22 from the light source 18 and generates a collimated light beam 24.

[0121] The light beam 22 is transmitted to the off-axis parabolic reflector 32 by a coupling system (not shown). The coupling system expands the light beam 22 so that it is projected over the entire range (including substantially the entire range) of the off-axis parabolic reflector 32. The coupling system includes a light pipe (which can be straight or tapered to expand the light), receives the light from the light source 18 at the first end, and provides the light beam 22 at the second end.

[0122] In an alternative embodiment (not shown), the coupling system is alternatively arranged and includes a prism configured to receive light from the light source and refract the light to provide a light beam, and other suitable devices including a combination of those disclosed.

[0123] The off-axis parabolic reflector 32 includes a curved reflector surface, which is generally arranged on a support with a flat rear surface. The flat rear surface of the parabolic reflector 32 is arranged to be aligned in the length direction plane defined by the length direction 100 and the depth direction 104. In particular, it is arranged inside the side panel of the housing 30. Such an arrangement can be convenient for assembly.

[0124] The off-axis parabolic reflector can bend the light beam 22 (by reflection) to enable compound collimation. By bending the light beam 22 in this way, the distance that the collimated sunlight component 12 is projected from between the light source 18 and the output aperture 8 becomes longer, and as a result, the perception of the sun being at infinity can be increased.

[0125] In a variant embodiment not shown, the off-axis parabolic reflector is inclined in one or more of the longitudinal plane around the depth or longitudinal axis, and the transverse plane defined by the transverse 102 and depth direction 104 around the transverse axis. The inclination can be provided in an adjustable amount, thereby enabling fine adjustment of the orientation of the reflector surface. The inclination can be less than 5 or 10 degrees.

[0126] In a variant embodiment not shown, the collimation system is alternatively arranged, which includes that it additionally includes a first collimator (e.g., a lens) upstream or downstream of the coupling system, and that it is arranged as one or more collimating lenses instead of or in addition to the off-axis parabolic reflector.

[0127] The collimated light generation system 4 includes a first optical expansion system 34 and a second optical expansion system 36. The first optical expansion system 34 is arranged to expand the collimated light beam 24 as the collimated sunlight component 12 in a first expansion direction, which is the transverse 102 in this example, across the output aperture 8. The second optical expansion system is arranged to further expand the collimated light beam 24 as the collimated sunlight component 12 in a second expansion direction, which is the longitudinal direction 100 in this example, across the output aperture 8. The optical expansion systems 32, 34 are arranged to maintain generally the same degree of collimation as that applied by the collimation system while expanding the collimated beam 24. The first optical expansion system 34 is separate from and upstream of the second optical expansion system 36.

[0128] In a variant embodiment (not shown), the first optical expansion system is integrated with the second optical expansion system, for example, by an integrated prism sheet.

[0129] The first optical expansion system 34 includes a first prism sheet 38. As best seen in FIG. 2, the plane of the first prism sheet 38 on which the associated prisms are aligned is tilted at an angle α with respect to the propagation direction of the incident collimated light beam 24 from the collimation system 20. This tilt is made substantially in the transverse plane (defined by the transverse direction 102 and the depth direction 104) and around the depth axis 104. The tilt angle can be 5 to 30 degrees. The tilt is made such that the collimated light beam 24 is projected over substantially all of the first prism sheet 34. The prisms of the first prism sheet 38 reflect and / or refract the collimated light beam 24 individually over the length of the first prism sheet 38. The first prism sheet 38 is configured to project the first expanded collimated light beam 40 substantially in the longitudinal direction 100. The first expanded collimated light beam 40 is thus expanded into the transverse component of the length of the first prism sheet 38 disposed substantially as the lateral dimension of the output aperture 8.

[0130] It should be understood that with such an arrangement, the first prism sheet 38 can expand the incident collimated light beam 24 (in a direction perpendicular to the propagation direction) by a factor greater than 2, 3, or 5. The maximum expansion of 10 or 20 or 30 can be specified by the power of the light source and the resolution of the individual prisms.

[0131] Referring to FIG. 3, the first prism sheet 38 is further tilted with respect to the transverse plane and around the transverse axis 102. The tilt angle can be 5 to 30 degrees. This allows the first expanded collimated light beam 40 to be projected onto an optional field-of-view control system 42 including a reflector system 44, as will be described later.

[0132] The light source 18 and the optionally provided coupling system are arranged so as not to interfere with the light projected from the first prism sheet 38 and / or the off-axis parabolic reflector 32.

[0133] Referring to FIG. 2, the light source 18 and the optionally provided coupling system are arranged in the longitudinal direction 100 behind the reflective surface of the first prism sheet 38. Referring to FIGS. 3 and 4, the light source 18 and the optionally provided coupling system are arranged in the depth direction 104 above the off-axis parabolic reflector 32 and the first prism sheet 38, between the said components and the output aperture 8.

[0134] In addition, in a modified embodiment not shown, it should be understood that the light source 18 and the optionally provided coupling system can be arranged so as not to interfere with the light projected from below the first prism sheet 38 and / or the off-axis parabolic reflector, for example the off-axis parabolic reflector 32 and the first prism sheet 38, or in other suitable arrangements.

[0135] The field-of-view control system 42 is arranged so as to obscure at least part of the collimated light generation system 4 and / or the diffused light generation system 6 when viewed through the output aperture 8.

[0136] The reflector system 44 is configured so that the collimating system 20, the light source 18, and the first prism sheet 38 are hidden from the observer when viewed through the output aperture 8. The reflector system 44 further increases the distance at which the collimated sunlight component 12 is projected between the light source 18 and the output aperture 8, which can increase the perception of the sun at infinity.

[0137] The reflector system 44 includes a first reflecting member 46 (for example, a mirror) for specular reflection of the first expanded collimated light beam 40. The first reflecting member 46 is aligned with the opposite end of the output aperture 8 of the device within the plane of the output aperture 8. The first reflecting member 46 reflects the first expanded collimated light beam 40 to a second reflecting member 48.

[0138] The reflector system 44 includes a subsequent second reflecting member 48 (e.g., a mirror) for specular reflection of the first expanded collimated light beam 40. The second reflecting member 48 is disposed at the end of the device on the substantially horizontal plane opposite to the first prism sheet 38. The second reflecting member 48 is tilted by an angle Ψ around the lateral axis 102 into the lateral plane. The tilt angle can be between 5 and 30 degrees.

[0139] The second reflecting member 48 reflects the first expanded collimated light beam 40 and forms part of the second optical expansion system 36 as described below.

[0140] The reflector system 44 includes a shelf member 50 which is aligned parallel to the first expanded collimated light beam 40 reflected from the second reflecting member 48. The shelf member 50 diffusely reflects and has a white outer surface. The shelf member 50 impedes / reduces the visibility of the collimating system 20, the light source 18, and the first prism sheet 38 (e.g., from a specific viewing angle) when viewed through the output aperture 8.

[0141] In an alternative embodiment (not shown), the shelf member is alternatively aligned, e.g., it is arranged to tilt in the direction of the proximal collimated light beam so that the collimated light beam casts a shadow on the shelf member, and it can be formed with another surface finish, e.g., for specular reflection, and it can be arranged to hide the collimating system and the light source but not the first prism sheet, the first reflecting member is tilted towards the output aperture, the second opposing member is aligned in the lateral plane, and it can include a Fresnel device to provide the same as the tilted specular reflection described above, and the shelf member can be omitted.

[0142] The second optical expansion system 36 includes a second prism sheet 52. The plane on which the associated prisms of the second prism sheet 52 are aligned is aligned with the output aperture 8.

[0143] As described above, the second reflecting member 48 is tilted such that the first expanded collimated light beam 40 is projected substantially over the entire second prism sheet 52. The prisms of the second prism sheet 52 refract and / or reflect the first expanded collimated light beam 40 individually over the length of the second prism sheet 52 and are transparent such that light is transmitted therethrough as the second expanded collimated light beam 54. The second prism sheet 52 is configured to project the second expanded collimated light beam 54 generally in the depth direction 104 (e.g., at an angle of 0 to 40 degrees with respect thereto). The second expanded collimated light beam 54 is thus expanded into the longitudinal component of the length of the second prism sheet 52 which is the longitudinal dimension of the output aperture 8.

[0144] The second expanded collimated light beam 54 is transmitted through the diffuser 26 as described above. The second expanded collimated light beam 54 is projected as the collimated sunlight component 12 through the output aperture 8.

[0145] In a variant embodiment, the second prism sheet is alternatively arranged, which includes being angled with respect to the output aperture and in particular extending only over a part of the output aperture, and also includes that one or both prism sheets are replaced by optical devices of similar function, such as a single prism.

[0146] The field of view control system 42 further includes a field of view angle dependent member 56, which is configured to be optically transparent from a first field of view angle range and at least partially optically opaque from a second different field of view angle range. An example of a suitable material is the Lumistry Vision Control Film, model W - 0055, provided by Lumistry products. The said example transitions from transparent to semi - white at a field of view angle greater than 55 degrees. The field of view angle dependent member 56 is arranged within the plane of the output aperture 8 so as to overlap therewith entirely. This is downstream of the diffuser 26 and the second prism sheet 52.

[0147] In a variant embodiment (not shown), the viewing angle dependent member may be omitted, or alternatively arranged, which may include, for example, overlapping only a particular portion of the output aperture when a collimated light source is visible or is arranged upstream of the diffuser.

[0148] [Second to Fourth Embodiments] In a variant embodiment (not shown), various structural improvements of the first embodiment may be made, all of which are not mutually contradictory when related to other embodiments.

[0149] In the second embodiment, the second beam expansion system is omitted, whereby the first prism sheet projects light to the output aperture. In such a variant, the first prism sheet may be reflective or transmissive as in the first embodiment, and the light to the output aperture is reflected from or transmitted through the second prism sheet, respectively.

[0150] In the third embodiment, the second prism sheet is alternatively reflective, whereby it reflects light to the output aperture, and the output aperture is arranged at the other end of the device in the depth direction (not having transmissivity as in the case of the first embodiment). With such an arrangement, the first reflecting member may be omitted, whereby the first prism sheet directly transmits light to the second reflecting member, which transmits the light to the second prism sheet, or alternatively, the first prism sheet directly transmits light to the second prism sheet (thus the reflector system may be omitted).

[0151] In the fourth embodiment, the reflector system is omitted and the first prism sheet directly transmits light to the second prism sheet. In such an embodiment, the second prism sheet may be transmissive and the light to the output aperture is transmitted through the second prism sheet.

[0152] [Fifth Embodiment] Referring to FIGS. 5 and 6, in the fifth embodiment of the apparatus 2, there are two collimated light sources, both of which are expanded by a shared beam expansion system as described below. The fifth embodiment shares all of the mutually compatible features and variants common to the first embodiment, which are not repeated for the sake of brevity. Where there is no contradiction, the second to fourth embodiments may also implement two collimated light sources as in the fifth embodiment.

[0153] In the fifth embodiment, the collimated light generation system 4 includes a first collimated light source 16 and a second collimated light source 60. The collimated light generation system 4 is arranged to have a first collimated light beam 24 and a second collimated light beam 62 that are both projected through the output aperture 8.

[0154] The first collimated light beam 24 and the second collimated light beam 62 overlap each other and have common axes 108, 110. The overlapping collimated light beam 64 is projected as the collimated sunlight component 12 through the output aperture 8.

[0155] In a variant embodiment (not shown), the collimated light beams overlap each other without aligning their central axes. For example, the axes are aligned in the longitudinal direction and offset in the transverse direction, or vice versa.

[0156] The first collimated light source 16 includes a dedicated light source 18 and a collimation system 20. The second collimated light source 60 includes a dedicated light source 18 and a collimation system 20.

[0157] By two separate light sources, each light beam of the first and second collimated light sources can be individually controllable by an electrical circuit configuration. In a first variant, the first and second light beams can be configured to be projected with beams of different colors (which can be achieved by a color system), whereby the collimated sunlight component can be controlled in color (e.g., in terms of CCT) and / or intensity by controlling the intensity of the light source. In a second variant, the first and second light beams can be configured to be projected with beams of the same color (including substantially the same color), whereby the collimated sunlight component can be controlled in intensity by controlling the intensity of any of the collimated light sources. For example, in a low energy mode, one of the collimated light sources can be turned off.

[0158] In an embodiment of a variant not shown, the first collimated light source and the second collimated light source include separate beams obtained from a common single light source and / or collimation system.

[0159] In this specification, for the sake of brevity, the arrangement of the first collimated light source 16 is generally described and is the same as in the first embodiment. Thus, the same description applies to the second collimated light source 60, since it is symmetrically arranged around the central longitudinal axis of the device.

[0160] As can be best seen in FIG. 5, the light source 18 obliquely projects a light beam having a substantial component in the longitudinal direction 100 across the plane of the output aperture 8 towards the off-axis parabolic reflector 32. The light source 18 also projects components in the opposite lateral direction 104 and depth direction 104.

[0161] As can be best seen in FIG. 5, the off-axis parabolic reflector 32 is tilted in the longitudinal direction 100, whereby the longitudinal component of the light beam 22 incident on the off-axis parabolic reflector 32 is then reflected in the longitudinal direction opposite to the collimated light beam 24. The off-axis parabolic reflector 32 is also tilted in the lateral 102 direction and the depth direction 104, whereby the collimated light beam 24 undergoes a change in direction in said directions.

[0162] As a result, the off-axis parabolic reflector 32 of the collimating system 20 is arranged to project the collimated light beam 24 in a manner that is substantially oblique across the plane of the output aperture 8 (e.g., not aligned with the longitudinal direction 100 or the lateral direction 102 and not inclined with respect thereto) and at least partially overlapping.

[0163] The off-axis parabolic reflector 32 is arranged to partially overlap the output aperture 8 by virtue of the inclination. In a variant embodiment (not shown), the off-axis parabolic reflector is arranged not to overlap the output aperture, for example, it can be retracted laterally from the output aperture.

[0164] The collimated light generating system 4 includes a mixing element, which in this example is the first prism sheet 38. The first prism sheet 38 is arranged to be aligned with the lateral direction 102 and has an inclination angle β with respect to the lateral plane and around the lateral axis 102.

[0165] Unlike the first example, the reflector system 44 is omitted and the first prism sheet 38 is projected directly onto the second prism sheet 52 (as described for the fourth embodiment).

[0166] The first prism sheet 38 is arranged symmetrically around the central longitudinal axis and includes individually symmetric prism members. In this way, the prism receives the collimated light beam 24 from the first collimated light source 16 and the second collimated light beam 62 from the second collimated light source 60 from any of the related directions and projects a superimposed collimated light beam 64. The central axes 108, 110 of the collimated light beams 24, 62 can be visualized as intersecting at a common intersection point (which is at its center) on the first prism sheet 38 from which the superimposed collimated light beam 64 is projected.

[0167] The light source 18, at least a part of the off-axis paraboloidal reflector 32, and the first prism sheet 38 are positioned so as not to overlap with the output aperture 8 when viewed in a plane defined by the lateral and longitudinal directions, as shown in FIG. 5. Thereby, their visibility from the output aperture 8 is reduced. More particularly, the light source 18 is disposed generally at the same position in the depth direction 104 towards the output aperture 8, so that its visibility through the output aperture 8 is reduced / eliminated.

[0168] In an embodiment including a coupling system for coupling the light beam 22 to the off-axis paraboloidal reflector 32, the coupling system (e.g., a prism or a light pipe) is arranged so as not to overlap with the output aperture 8.

[0169] The light source 18 and the optional coupling system are arranged so as not to interfere with the light projected from the first prism sheet 38 and / or the off-axis paraboloidal reflector 32. Unlike the first embodiment, this is achieved by arranging the light source and the optional coupling system so as not to overlap with the output aperture. Such an arrangement can ensure that the light source and the optional coupling system are not visible through the output aperture and do not interfere with the light projected from the collimating system and / or the first prism sheet.

[0170] [Sixth to Ninth Embodiments] In a sixth embodiment not shown, the first and second collimated light sources are alternatively arranged at the longitudinal ends on both sides of the device, and are substantially halved in the lateral direction, similar to the apparatus of the fifth embodiment, whereby there are two separate first prism sheets, each receiving light from one of the collimated light sources, and the second prism sheet functions as a mixing element with an intersection in the center thereof.

[0171] In a seventh embodiment not shown, the fifth embodiment is implemented with a single collimated light source, and the device is substantially halved in the lateral direction, whereby the functional implementation of the first embodiment is provided for the collimated light source of the fifth embodiment.

[0172] In an eighth embodiment not shown, the fifth or first embodiment may be configured such that a plurality of collimated light generation systems are arranged in a row, whereby each of said systems provides a separate collimated sunlight component as a rectangle adjacent laterally across the common output aperture. In such an embodiment, the light sources and collimating systems of the collimated light generation systems project from the same longitudinal end of the device, i.e., from both ends, and for example they may be staggered, and it should be understood that they are sequentially from the opposite ends. In such an embodiment, the collimated light beams are longitudinally aligned, laterally, and have offset central axes.

[0173] In a ninth embodiment not shown, the fifth embodiment may be configured such that two collimated light generation systems are arranged at opposite longitudinal ends of the device, whereby each of said systems provides a separate collimated sunlight component as a rectangle adjacent longitudinally across the output aperture. In such an embodiment, the collimated light beams are laterally aligned, longitudinally, and have offset central axes.

[0174] [Tenth Embodiment] Referring to FIGS. 7 - 10, in the tenth embodiment of the device 2, the fifth embodiment is configured to include: A first prism 38 sheet is transparent and collimated light passes through it, and a reflector system 44 similar to the first embodiment is implemented as described below. The tenth embodiment shares all non - conflicting features and variants common to the first embodiment, which are not repeated for brevity.

[0175] In the tenth embodiment, the collimated light generation system 4 includes a first collimated light source 16 and a second collimated light source 60. The collimated light generation system 4 is arranged such that both the first collimated light beam 24 and the second collimated light beam 62 are projected through the output aperture 8.

[0176] Similar to the fifth embodiment, the first collimated light beam 24 and the second collimated light beam 62 are superimposed on each other, and they have a common central axis 108, 110. The superimposed collimated light beam 64 is projected as the collimated sunlight component 12 through the output aperture 8.

[0177] In a modified embodiment not shown, the collimated light beams are superimposed on each other with their central axes misaligned, for example, the axes may be aligned in the length direction and offset in the transverse direction, or vice versa, and the second collimated light source may be omitted.

[0178] The first collimated light source 16 includes a dedicated light source 18 and a collimating system 20. The second collimated light source 60 includes a dedicated light source 18 and a collimating system 20.

[0179] With two separate light sources, each light beam of the first and second collimated light sources may be individually controllable by an electrical circuit configuration. In the first embodiment, the first and second light beams are configured to be projected as beams of different colors (which can be achieved by a color system), whereby the collimated sunlight component can be controlled in terms of color (e.g., of a CCD) and / or intensity by controlling the intensity of the light sources. In a second modification, the first and second light beams may be configured to be projected as beams of the same color (including substantially the same color), whereby the collimated sunlight component can be controlled in terms of intensity by controlling the intensity of either collimated light source. For example, in a low energy mode, one of the collimated light sources may be turned off.

[0180] In a modified embodiment not shown, the first collimated light source and the second collimated light source include separate beams obtained from a common single light source and / or collimating system.

[0181] In this specification, for the sake of brevity, the arrangement of the first collimating light source 16 is generally described and is the same as in the case of the first embodiment. Therefore, it is understood that the same description also applies to the second collimating light source 60, because it is symmetrically arranged around the central longitudinal axis of the device 2.

[0182] As can be best seen in FIG. 7, the light source 18 projects the light beam 22 with a substantial component in the longitudinal direction 100 opposite to the collimating system 22 arranged as the off-axis parabolic reflector 32, obliquely across the plane of the output aperture 8. The light source 18 also projects with components in the opposite lateral direction 104 and depth direction 104.

[0183] As can be best seen in FIGS. 7 and 10, the off-axis parabolic reflector 32 is tilted in the longitudinal direction 100, and the opposite longitudinal component of the light beam 22 incident on the off-axis parabolic reflector 32 is then reflected as the collimated light beam 24 in the longitudinal direction 100. The off-axis parabolic reflector 32 is arranged to overlap with the output aperture due to the said tilt. The off-axis parabolic reflector 32 is also tilted in the lateral direction 102 and the depth direction 104, and the collimated light beam 24 undergoes the said direction changes.

[0184] As a result, the off-axis parabolic reflector 32 of the collimating system 20 is arranged to project the collimated light beam 24 substantially obliquely (e.g., not aligned with the longitudinal direction 100 or the lateral direction 102) across the plane of the output aperture 8 in an overlapping manner.

[0185] The collimated light generation system 4 includes a mixing element, which in this embodiment is the first prism sheet 38. As can be best seen in FIG. 8, the first prism sheet 38 is arranged to be aligned with the lateral direction 102 and has a small tilt angle β around the lateral axis 102 with respect to the lateral plane.

[0186] The first prism sheet 38 is arranged to tilt towards the off-axis parabolic reflector 32 as described above and forms part of the first optical expansion system 34.

[0187] The first prism sheet 38 is symmetrically arranged around the central longitudinal axis and includes individually symmetric prism members. In this way, the prism receives the collimated light beam 24 from the first collimated light source 16 and the second collimated light beam 62 from the second collimated light source 60 from any of the related directions and projects a superimposed collimated light beam 64. The central axes 108, 110 of the collimated light beams 24, 62 can be visualized to intersect at a common intersection point (which is at its center) on the first prism sheet 38 from which the superimposed collimated light beam 64 is projected.

[0188] Unlike the first embodiment, the reflector system 44 is arranged as a single reflecting member 46. The first prism sheet 38 projects onto the reflecting member 46, which then projects onto the second prism sheet 52. The first reflecting member 46 (e.g., a mirror) is for specular reflection of the first expanded collimated light beam 40. The first reflecting member 46 is arranged at the end of the device opposite the first prism sheet 38 in a substantially lateral plane. As best seen in FIG. 8, the first reflecting member 46 is tilted by an angle ψ around the lateral axis 102 with respect to the lateral plane. The tilt angle can be between 5 and 30 degrees. The first reflecting member 44 reflects the first expanded collimated light beam 40 to the second optical expansion system 36 and forms a part thereof, as described above.

[0189] The light source 18 is positioned to overlap the output aperture 8 when viewed in the plane defined by the lateral and longitudinal directions, as shown in FIG. 7. The light source 18 projects the light beam 22 obliquely to the off-axis parabolic reflector 32 across the plane in which the output aperture 8 is arranged. In an embodiment including a coupling system for coupling the light beam 22 to the off-axis parabolic reflector 32, the coupling system (e.g., a light pipe as described for the first embodiment) is arranged to overlap the output aperture 8.

[0190] The light source 18, the optionally provided coupling system, and the off-axis parabolic reflector 32 and the first prism sheet are arranged so as not to interfere with the light projected from the first prism sheet 38 and the off-axis parabolic reflector 32 and to be at least partially unclear when viewed from outside the output aperture 8 (as described for the first embodiment).

[0191] In particular, as can be best seen in FIG. 8, the shelf member 50 is mounted in combination with the first reflecting member 46 to avoid the interference by reflecting light around these components and by making at least partially unclear the way they are seen from outside the output aperture 8.

[0192] As can be best seen in FIG. 7, the light source 18 of the first collimated light source 16 projects in a substantially opposite lateral direction 102, and the light source 18 of the second collimated light source 60 projects in the substantially lateral direction 102. With such an arrangement, the light sources can be conveniently arranged on the same carrier and / or arranged so as not to interfere with each other.

[0193] As used herein, both the description in the form of "at least one of A, B, or C" and the description of "at least one of A, B, and C" use the exclusive "or" and the exclusive "and", and these descriptions cover all possible combinations and some permutations of A, B, and C, namely A only, B only, C only, A and B in any order, A and C in any order, B and C in any order, and A, B, C in any order. There may be more than three or fewer features in such a description.

[0194] In the claims, any reference signs enclosed in parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of other elements or acts than those listed in a claim. Further, the articles "a" and "an" are defined as one or more when used in this specification. Also, the phrases "at least one" and "one or more" preceding elements in the claims do not, by virtue of the introduction of an additional claim element by the indefinite article "a" or "an", imply that a claim containing such introduced claim element is limited to an invention having only one such element, even if the same claim contains the phrases "one or more" or "at least one" and the indefinite article "a" or "an". The same applies to the use of the definite article. Unless otherwise specified, terms such as "first" and "second" are used to arbitrarily distinguish between elements being described. Therefore, these terms are not necessarily intended to indicate any temporal or other precedence of such elements. Merely because certain means are recited in mutually different claims does not indicate that a combination of these means cannot be used advantageously.

[0195] Unless otherwise expressly stated to be in conflict, or the physics or other of the embodiments, examples, or claims prevent such a combination, the features of the above-described embodiments and examples, and of the following claims, can be integrated together in any suitable arrangement and in any suitable combination, particularly in such a way. This is not limited to only any expressly stated benefits, but instead can result from "after-the-fact" benefits. That is, the combination of features is not limited by the form in which they are described, particularly the subordinated form (e.g., numbering) of the examples, embodiments, or claims. Further, this also applies to phrases such as "in one embodiment", "according to an embodiment", etc., which are merely stylistic forms of circumlocution and are not to be construed as limiting the features that follow to another embodiment for any other instance of the same or similar circumlocution. That is, references to "an", "one", or "some" embodiments can also be references to one or more and / or all of the disclosed embodiments or combinations thereof. Similarly, references to "the" embodiment need not be limited to the immediately preceding embodiment.

[0196] The above description of one or more implementations provides illustration and explanation, but is not intended to be exhaustive or to limit the scope of the invention to the exact forms disclosed. Improvements and changes are possible in light of the above teachings or can be acquired from practice of the various implementations of this disclosure.

Description of Reference Numerals

[0197] 2 device 4 collimated light generation system 16 first collimated light source 18 light source 22 light beam 20 collimation system 32 off-axis parabolic reflector 24 collimated light beam 108 central axis of the light beam 34 first optical expansion system 38 first prism sheet (mixing element) 40 First expanded collimated light beam 36 Second optical expansion system 52 Second prism sheet 54 Second expanded collimated light beam 60 Second collimated light beam 62 Second collimated light beam 110 Central axis of the light beam 42 Field of view control system 44 Reflector system 46 First reflecting member 48 Second reflecting member 50 Shelf member 56 Field-of-view angle-dependent member 6 Diffused light generation system 26 Diffuser 28 Light source 8 Output aperture 10 Output light 12 Collimated sunlight component 14 Diffused sky background component 30 Housing

Claims

1. An optical display device arranged to create a perception of a sky scene in the output light, A collimated light generation system including a collimated light source for generating a collimated light beam, a first optical expansion system, and a second optical expansion system, A diffused light generation system, An output aperture onto which the output light is projected, Including, The diffused light generation system is arranged to generate a diffused sky light component in the output light, and the collimated light generation system is arranged to generate a collimated sunlight component in the output light, The first optical expansion system is arranged to expand the collimated light beam as the collimated sunlight component in a first expansion direction across the output aperture, The second optical expansion system is arranged to separately and subsequently expand the collimated light beam as the collimated sunlight component in a second expansion direction across the output aperture, The second expansion direction is different from the first expansion direction, an optical display device.

2. The first optical expansion system is separate from and upstream of the second optical expansion system, and the first optical expansion system does not expand the collimated light beam in the second direction, and / or the second optical expansion system does not expand the collimated light beam in the first expansion direction, the optical display device according to claim 1.

3. The first and second optical expansion systems are arranged for uniform expansion, and / or consist of a linear expansion of the collimated light in the associated expansion direction, the optical display device according to claim 1 or 2.

4. The average divergence angle of the optically expanded collimated light beam is within 5% or 10% of the divergence angle of the collimated light beam, the optical display device according to any one of claims 1 to 3.

5. The collimated light beam is expanded at least 3 times or 5 times in both directions, the optical display device according to any one of claims 1 to 4.

6. The collimated light beam is expanded in at least one of the directions up to the range of the output aperture in that direction, the optical display device according to any one of claims 1 to 5.

7. The first and second expansion directions are orthogonal to each other across the output aperture, the optical display device according to any one of claims 1 to 6.

8. The optical display device according to claim 7, wherein the output aperture extends in length and in the lateral direction, the first direction is aligned in the lateral direction, and the second direction is aligned in the length direction.

9. The first optical expansion system includes a prism sheet that is arranged to be inclined in the propagation direction of the collimated light beam and expands the collimated light beam into a first expanded collimated light beam. The optical display device according to any one of claims 1 to 8.

10. The optical display device according to claim 9, wherein the prism sheet is arranged such that the collimated light beam passes therethrough.

11. The optical display device according to claim 9 or 10, wherein the prism sheet is arranged to be inclined with respect to the inclined aperture.

12. The second optical expansion system includes a second prism sheet that is arranged to be inclined in the propagation direction of the first expanded collimated light beam and expands the first collimated light beam into a second expanded collimated light beam. The optical display device according to claim 9 or 10.

13. The optical display device according to claim 12, wherein the second prism sheet is arranged across the output aperture, and projects the second expanded collimated light beam as the collimated sunlight component through the output aperture.

14. The optical display device according to claim 13, wherein the second prism sheet is arranged in the same plane as the output aperture.

15. The collimated light source includes a light source and a collimating system that receives light from the light source and generates the collimated light beam therefrom, and the collimating system is an off-axis parabolic reflector. The optical display device according to any one of claims 1 to 14.

16. The collimated light source includes a coupling system that projects the light from the light source to the collimating system, and the coupling system includes one or more of a prism, a light guide, and a lens. The optical display device according to claim 15.

17. The collimated light source is arranged so as not to interfere with the light projected from the collimating system and / or the prism sheet. The optical display device according to claim 16 or claim 15 or claim 9.

18. A kit of parts assembled into the optical display device according to any one of claims 1 to 17.

19. A method of creating a perception of a sky scene, comprising Expanding the collimated light beam in a first direction when viewed at the output aperture, then expanding the light from the collimated light beam in a different second direction when viewed at the output aperture, and outputting the expanded collimated light as a collimated sunlight component. A method comprising the above steps. **Claim 20** Transmitting light to a diffused light generation system to generate a skylight component, and outputting the diffused light as the skylight component. The method according to claim 19, comprising the above steps.

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