Acoustic panel having lighting properties

Abstract

The invention provides an acoustic panel comprising a plurality of parallel-arranged elongated cavities, wherein each cavity has a first cavity wall and a second cavity wall tapering to a cavity back end and defining a cavity opening angle (γ) having a value in the range of 0°<γ<90°, wherein the first cavity wall and the second cavity wall comprise a light-reflective material, wherein each elongated cavity at the cavity back end of the elongated cavity accommodates a light source having a light exit surface, wherein the first cavity walls hide the light exit surfaces of the light sources when the acoustic panel is viewed along a normal to the acoustic panel, and wherein the acoustic panel further comprises sound reducing material.

Claims

1. An acoustic panel comprising: one or more elongated cavities, wherein each cavity of the one or more elongated cavities has a first cavity wall, a second cavity wall, a cavity opening between the first cavity wall and the second cavity wall, and a cavity back end, wherein the cavity back end opposes said opening, the cavity back end is disposed farther from said opening than said first cavity wall and the cavity back end is disposed farther from said opening than said second cavity wall, wherein at least one given cavity of the one or more elongated cavities accommodates a light source having a light exit surface, wherein the light source is configured to provide light source light emanating from the cavity opening of the at least one given cavity, wherein the first cavity wall or the second cavity wall hides the light exit surface of the light source when the acoustic panel is viewed along a normal to the acoustic panel, and wherein the acoustic panel further comprises sound reducing material; and a support frame which holds the light source at the cavity back end of the at least one given cavity, wherein the first cavity wall and the second cavity wall of the at least one given cavity taper to the cavity back end of the at least one given cavity and define a cavity opening angle (γ) having a value in the range of 0°<γ<90°.

2. The acoustic panel according to claim 1, wherein the first cavity wall and the second cavity wall of the at least one given cavity comprise a diffusely reflective material.

3. The acoustic panel according to claim 2, wherein the one or more elongated cavities form a continuous area, substantially without vertical facets of the sound reducing material in between the one or more elongated cavities.

4. The acoustic panel according to claim 3, wherein 35°≦γ≦75°.

5. The acoustic panel according to claim 4, wherein the one or more elongated cavities are arranged in parallel.

6. The acoustic panel according to claim 5, wherein parallel-arranged elongated bars are connected to the support frame, said elongated bars comprising the sound reducing material, said elongated bars further being configured to provide at least one of the one or more elongated cavities between two adjacent elongated bars of the parallel-arranged elongated bars, wherein the one or more elongated cavities is a plurality of elongated cavities.

7. The acoustic panel according to claim 6, wherein the first cavity wall of the at least one given cavity has a first cavity wall angle (α) with the normal to the acoustic panel in the range of 15-65°, the second cavity wall has a second cavity wall angle (β) with the normal to the acoustic panel in the range of 25-80°, wherein the first cavity wall angle (α) is smaller than the second cavity wall angle (β).

8. The acoustic panel according to claim 7, wherein the first cavity wall of the at least one given cavity has a first cavity wall angle (α) in the range of 15-35° and wherein the second cavity wall of the at least one given cavity has a second cavity wall angle (β) in the range of 35-55°.

9. The acoustic panel according to claim 8, wherein the at least one given cavity is a plurality of given cavities that have a pitch (p) in the range of 2-25 cm.

10. The acoustic panel according to claim 9, wherein one or more of the given cavities comprise a plurality of light sources.

11. The acoustic panel according to claim 10, wherein the acoustic panel comprises a panel element of sound reducing material comprising said one or more of the given cavities or elongated cavity sections.

12. The acoustic panel according to claim 11, further comprising reflection-glare reducing bars, configured perpendicularly to the plurality of elongated cavities and configured to block and/or redirect direct lighting of an item in front of the acoustic panel with light rays from the plurality of light sources in a plane perpendicular to the acoustic panel and parallel to the reflection-glare reducing bars.

13. The acoustic panel according to claim 12, comprising said one or more elongated cavities on two opposing sides of the frame, and wherein light emanates from the two opposing sides of the acoustic panel.

14. The acoustic panel according to claim 1, wherein the acoustic panel is configured as an office divider wall configured to delineate work spaces.

15. A lighting system for a work space, the lighting system comprising: a desk for being disposed on a floor; and a divider wall positioned to block a view of said desk from a person seated and/or standing on said floor and outside of said work space in which the lighting system is disposed, wherein the divider wall comprises at least one acoustic panel including: one or more elongated cavities, wherein each cavity of the one or more elongated cavities has a first cavity wall, a second cavity wall, a cavity opening between the first cavity wall and the second cavity wall, and a cavity back end, wherein the cavity back end opposes said opening, the cavity back end is disposed farther from said opening than said first cavity wall and the cavity back end is disposed farther from said opening than said second cavity wall, wherein at least one given cavity of the one or more elongated cavities accommodates a light source having a light exit surface, wherein the light source is configured to provide light source light emanating from the cavity opening of the at least one given cavity and the light source is disposed at the cavity back end of the at least one given cavity, wherein the first cavity wall or the second cavity wall hide the light exit surface of the light source when the acoustic panel is viewed along a normal to the acoustic panel, and wherein the acoustic panel further comprises sound reducing material.

16. The lighting system of claim 15, wherein the divider wall is configured such that said light source provides task lighting that illuminates the desk directly from the light exit surface.

17. The lighting system of claim 16, wherein the at least one acoustic panel comprises: a support frame which holds the light source at the cavity back end of the at least one given cavity, wherein the first cavity wall and the second cavity wall of the at least one given cavity taper to the cavity back end of the at least one given cavity and define a cavity opening angle (γ) having a value in the range of 0°<γ<90°.

18. The lighting system of claim 16, wherein the divider wall is a desk divider or a room divider.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

(2) FIGS. 1a-1j schematically depict some embodiments and variants of the invention;

(3) FIGS. 2a-2c schematically depict some embodiments of the light source(s) for the acoustic panel;

(4) FIGS. 3a-3b schematically depict some applications of the acoustic panel; and

(5) FIGS. 4a-4e schematically depict some further embodiments of the acoustic panel.

(6) The drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(7) FIGS. 1a-1j schematically depict some embodiments and variants of the invention.

(8) FIG. 1a schematically depicts an embodiment of the acoustic panel 100 in side view. The acoustic panel 100 comprises a support frame 110 with parallel-arranged elongated bars 120 connected to said support frame 110. The elongated bars 120 comprise sound reducing material, indicated with reference numeral 2.

(9) As can be seen from the figures, the elongated bars 120 are configured to provide elongated cavities 130 (also indicated as cavities 130) between adjacent elongated bars 120. As a result, the acoustic panel 100 comprises a plurality of said elongated cavities 130.

(10) Each cavity 130 has a first cavity wall 131 and a second cavity wall 132 tapering in the direction of the support frame 110 and defining a cavity opening angle • having e.g. a value in the range of 35-75°.

(11) The cavity 130 has a cavity axis (or plane in fact) 77, which can be considered a bisector (plane). This bisector (plane) has an angle • with a normal 113 to the frame 110 in the range of e.g. 15-80°. During use of the panel 100, this bisector (plane) may point towards the earth's surface, when viewing this plane from the acoustic panel 100 (however, other embodiments are also possible, see also below). The first cavity walls 131 hide the light exit surfaces 12 of the light sources 10 when the acoustic panel 100 is viewed along a normal to the support frame 100.

(12) The first cavity wall 131 and the second cavity wall 132 may, in an embodiment, comprise a light reflective material. This may be a separate reflector, such as a coating, or the acoustic material 2 may also have light reflective properties. The reflectors are indicated with reference numerals 1131 (first cavity wall reflector) and 1132 (second cavity wall reflector), respectively.

(13) Each elongated cavity 130 accommodates, at a back end 138 (here a tapering end) of the cavity 130, a light source 10 having a light exit surface 12. This light source 10 may be connected to the frame. In general, a plurality of light sources, or at least a plurality of light exit surfaces in each elongated cavity, are applied. The cavity back end is one end of the elongated cavity, and the cavity opening is the other end of the cavity 130. The fact that in FIG. 1a each cavity 130 accommodates a light source 10 (or a plurality of light sources) is an example of one of the embodiments.

(14) Here, each first cavity wall 131 has a first cavity wall angle • with a normal to the acoustic panel (or in this case also a normal to the support frame 110), said angle • especially being in the range of 15-65°. Further, each second cavity wall 132 has a second cavity wall angle with a normal to the support frame 110, said angle • especially being in the range of 25-80°. The first cavity wall angle • is smaller than the second cavity wall angle •. In this way, the asymmetrically tapering cavities are obtained.

(15) Reference p indicates the pitch between the plurality of elongated cavities 130, and thereby also the pitch between the light sources in the respective elongated cavities 130.

(16) Reference LS indicates the first line of sight, when the panel 100 is in an upright position perpendicular to the earth's surface, and an observer in front of the panel 100 would change the observation position downwards from a position where the exit surface 12 of the light source 10 in a specific cavity 130 is hidden by the elongated bar over the light source to the first position where the light exit surface of that light source is visible. Alternatively, this line of sight can be defined as a line interconnecting the lowest part of the light exit surface of a specific light source 10 and the end tip (extremity or edge) of the first cavity wall, indicated with reference numeral 135, of the bar over said light source. The angle of this LS line with a normal to the surface is indicated with reference •. The value of this angle • is especially in the range of 15-65°, more especially in the range of 15-35°. As, in the present case, we are dealing with elongated cavities, the line of sight may also relate to a plane of sight.

(17) Reference 139 indicates an axis or elongation axis or elongated axis of the elongated cavity 130. Note that the elongation axes 130 of elongated cavities on a single acoustic panel 100 will preferably substantially be parallel arranged. Further, they will substantially be in a single plane. The normal 113 is configured so as to be perpendicular to such a plane (of elongation axes 130).

(18) Assuming the height H to be 150 cm, an observer at a distance of 10*150 cm from the acoustic panel 100, viewing along the normal 113, will not perceive direct lighting. Thus, the first cavity walls 131 (or in other embodiments the second cavity walls 132, see below) hide the light exit surfaces 12 from such an observer at such a distance. Thus, behind the first cavity wall end tip(s) 135 (or, in other embodiments, behind end tip 136 of the second cavity wall 132, see below) light exit surfaces 12 are hidden from such an observer.

(19) Reference W indicates the width (or depth) of the elongated cavity 130. This width may for instance be in the range of 0.5-20 cm, especially 1-20 cm, such as 1-10 cm, like at least 2 cm.

(20) FIG. 1b schematically depicts the tile-wise arrangement of the elongated bars. FIG. 1b schematically depicts a perspective view of the acoustic panel 100.

(21) The height of the panel is indicated by the letter H; the length of the panel is indicated by the letter L. Note that the cavities 130 and the elongated bars all substantially have the length L. The elongated cavities 130 have elongation axes 139. As will be clear to a person skilled in the art, these elongation axes 139 are in general arranged in parallel. The elongation axes 130 of a plurality of elongated cavities are in general in a single plane. The normal 113, indicated hereinabove to be a normal to the acoustic panel 100, will thus also be configured so as to be perpendicular to such a plane containing a plurality of elongation axes 139.

(22) In general, the edges of the cavities will not be closed, as can be seen in FIG. 1b, as this may have effects on the light distribution.

(23) The sound reducing material, such as a sound absorbing material, can be any material having such properties. Further, especially such material may be coated with a material that reflects light well, without blocking the propagation of sound through the coating. Such coatings are well known e.g. in the field of acoustic ceiling tiles. In case of micro-perforated plastic panels, the panels may be simply painted white (care being taken not to fill the holes with paint) or the panel material may be white plastic.

(24) Optionally, the acoustic panel comprises a plurality of subunits. This variant is also schematically depicted in FIG. 1b. Here, the acoustic panel 100 comprises a plurality (here 2) of panel elements 1100 comprising sound reducing material, and each panel element 1100 comprising elongated cavity sections 1130. The panel elements 1100 can be arranged with respect to each other, or even connected to each other, to allow adjacent elongated cavity sections 1130 on different panel elements 1100 to form the elongated cavities 130 across the plurality of panel elements 1100.

(25) Referring to FIGS. 1a-1b (and also the other embodiments described herein), each elongated cavity 130 is thus formed by first face 131 and second face 132, and has a cavity back end 138, wherein the light source(s) 10 may be arranged, and a cavity opening 230, through which light source light, indicated with reference numeral 11, may escape from the cavity. In this way, from one or more elongated cavities 130 light may emanate (during use of the acoustic panel as lighting unit). The cavity opening 230 has a height, which is indicated with reference cw. This will in general be the distance between the first cavity wall end tip 135 of the first cavity wall 131 and the second cavity wall end tip 136 of the second cavity wall 132. Especially these end tips define the cavity opening 230. The first cavity wall end tip is a kind of horizon beyond (here above) which an observer may not be able to see directly the light exit surface of the respective light source; the second cavity wall end tip is a kind of horizon beyond (here below) which an observer may not be able to see directly the light exit surface of the respective light source. The cavity opening 130 may have a height or width cw (cavity width) in the range of e.g. 2-10 cm. The length L of the elongated cavity may for instance be in the range of 1-5 m.

(26) FIGS. 1c and 1d schematically depict some alternative embodiments, wherein in the former the cavity walls 131 and 132 are straight, and in the latter these walls are curved. The length of the first cavity wall 131 is indicated with reference L2. In case a curved first cavity wall 131 is applied, the length is defined as the length of the straight line between the onset and the end tip 135 of the first cavity wall; likewise in case a curved second cavity wall 132 is applied, the length is defined as the length of the straight line between the onset and the end tip 136 of the second cavity wall. Here, the first cavity wall is convex-curved. Concave-curved first cavity walls may not be applied. The angles of the upper and second cavity walls 131,132 are also taken as the angles with the normal to the frame of straight lines between the respective onsets and the end tip 135 of the first cavity wall and the end tip of the second cavity wall 132. The end tip (or edge) of the second cavity wall 132 is indicated with reference numeral 136.

(27) The light source has an exit surface 12, which has a height H2. The light exit surface 12 may have a non-zero distance d1 to the first cavity wall 131, though in general this distance d1 will be kept small. The length of d1+H2 is especially substantially smaller than the length L1 of the first cavity wall. For instance, L1/(d1+H2)>2, especially >5, like >10. Especially, alternatively or additionally, W/(d1+H2)>2 (see also FIG. 1a.)

(28) FIGS. 1c and 1d schematically depict only two bars 120, which are here also indicated as upper bar 121 and lower bar 122. Note however that a lower bar for one cavity, may be an upper bar for another cavity (see FIGS. 1a-1b and 1e). Hence, these elongated bars 120, having sound reducing properties, are further simply indicated as (elongated) bars 120.

(29) FIG. 1e schematically depicts an embodiment of the acoustic panel having elongated bars 120 with acoustic material 2 on both sides of the frame. The bars 120, which are at the same height on both sides of the frame 110, may optionally be a single elongated bar 120. Likewise, optionally, the light sources 10 for providing light emanating from both sides of the acoustic panel 100 may be light sources that are able to provide light in opposite directions, like fluorescent tubes. However, in a specific embodiment, light sources, such as LEDs, are applied, on both sides of the frame 110, and configured to provide light through one cavity in one direction.

(30) Note that in FIG. 1a for instance, there are vertical elements between adjacent elongated cavities 130, whereas in FIG. 1e there are substantially no vertical elements (or facets) between adjacent elongated cavities 130. Vertical elements are elements which are situated on the cavity-opening side of the panel, and which are parallel to a plane through the acoustic panel 100. In FIGS. 1a and 1e, the plane through the acoustic panel is configured so as to be perpendicular to the plane of the drawing; in FIG. 1f such a plane is in the plane of the drawing.

(31) FIG. 1f schematically depicts an embodiment of the acoustic panel 100, seen from the backside (assuming that there are no bars 120 at the back (anymore)). Here, a frame of only two piles is shown, to which the elongated bars 120 are connected. Elongated light sources 10 may also be connected to those two piles. Note that all other types of frames may be possible.

(32) FIGS. 1g and 1h schematically depict some variants, which may also apply to the above-depicted embodiments and variants. The sawtooth variant in FIG. 1h allows a smaller pitch as compared to a panel with high elongated bars 120, as in FIG. 1g. FIG. 1h also indicates the height of the cavity back end 138, which height is indicated with reference H1. Especially, H1•H2 (see also above). Reference 111 indicates direct light; reference 112 indicates light reflected by the reflective walls. Hence, the light source light 11 may lead to direct light 111 and indirect light 112.

(33) FIG. 1h (and also 1e) shows a preferred embodiment of the invention, in which the slits or funnels form a continuous area, (substantially) without vertical facets of the acoustic absorbing material in between the funnels or slits (as is shown in FIGS. 1a-1d and 1g). In this embodiment, the whole area is diffusely lit, substantially without dark regions in between the funnels or slits. This avoids strong contrasts in luminance and hence avoids eye fatigue.

(34) FIGS. 1i and 1j schematically depict embodiments where the acoustic panel 100 further comprises reflection-glare reducing bars 140, configured perpendicularly to the elongated cavities 130 and configured to block direct lighting of an item in front of the acoustic panel with light rays from the light sources 10 in a plane perpendicular to the acoustic panel 100 and parallel to the reflection-glare reducing bars 140. FIG. 1i is a side view and FIG. 1j is a perspective view. The height of these reflection-glare reducing bars 140 is indicated with reference H3. Note that in these embodiments the height H3 of the reflection-glare reducing bars 140 is about the same as the height H of the panel 100. These bars may only be applied when the light exit surfaces 12 are discrete surfaces, such as in the case of LEDs. In that case, the width of the bars may be in the range of 1-20 times the width of the discrete surfaces of the light exit surfaces.

(35) FIGS. 2a-2c schematically depict some embodiments of light sources that are able to provide an elongated beam of light emanating from a cavity. FIG. 2a schematically depicts an elongated light source 10, such as a fiber or waveguide, with light outcoupling structures which provide the light exit surfaces 12. Hence, an elongated light source is depicted, which is indicated with reference numeral 510. The length of the elongated light source 510 is indicated with L3, and may be in the range of 80-100%, especially 90-100%, such as even 95-100% of the length L of the panel 100. FIG. 2b schematically depicts a bar with a plurality of light sources. The light source bar is indicated with reference numeral 610. For instance, this may be a unit with a plurality of LEDs. The pitch of the light exit surfaces 12 is indicated with reference P1, and is especially small, such as in the range of up to about 20 cm, especially in the range of up to 10 cm.

(36) Alternatively or additionally, the pitch of the light exit surfaces is defined to be smaller than the width (depth) of the cavity 130. Hence, in an embodiment, W>P1, such as W/P1>1.5, like W/P1>2.

(37) However, as indicated above, the elongated cavities may also comprise a single elongated light source, such as a fluorescent tube.

(38) FIG. 2c schematically depicts an embodiment, wherein (simply) a plurality of light sources, such as LEDs, are provided, such as on a support 1110, which support may be part of the frame 110 (or may be connected to an existing frame).

(39) FIGS. 3a and 3b schematically depict applications of the acoustic panel, as desk divider 101 and room divider 102, respectively. Reference numeral 7 indicates the working area. Reference numeral 111 indicates direct light; reference numeral 112 indicates light reflected by the reflective walls. These types of panels 100 are suitable for use in sectors in need of improved room acoustics and task light and/or daylight, e.g. open plan offices, restaurants, libraries, patient rooms. However, the acoustic panel 100 may also be used in applications other than those described and or depicted herein.

(40) FIG. 4a schematically depicts an embodiment of the acoustic panel 100 similar to those schematically depicted in FIGS. 1a, 1b and 1e. By way of example, not each elongated cavity 130 comprises light sources 10. FIG. 4b schematically depicts an embodiment wherein the first cavity wall 131 and the second cavity wall 132 are arranged in parallel, but both at non-zero angles with respect to the normal 113. Hence, also in this embodiment the light source(s) 10, or more especially their light exit surfaces 12, are hidden by the first cavity wall 131 (cf examples 4a-4b) or the second cavity wall 132, which are upper cavity walls. FIG. 4c is essentially the same as FIG. 4a, with the exception that the cavities point in another direction. For instance the embodiment of FIG. 4c might be obtained when the acoustic panel 100 of FIG. 4a is arranged upside down. Note that this may of course also apply to the other embodiments schematically depicted herein. FIG. 4d schematically depicts an embodiment wherein the elongated cavities have cavity axes (or planes in fact) 77 (which can be considered bisector(s) (planes); see also above), which make different angles with the normal 113. Or in other words, the cavity axes or planes 77 have mutual angles which are non zero. FIG. 4e schematically depicts an embodiment wherein the elongated cavities 130 are curved. Here, all elongated cavities are curved, but in an embodiment only a subset may be curved. Thus, the elongation axes 139 in this embodiment are curved. Note that in the schematically depicted embodiment, the elongated cavities 130 are still parallel arranged.

(41) An acoustic panel was built and used as desk divider. Substantially homogenous lighting of the desk was obtained, without direct light being visible by an observer sitting behind the desk.

(42) Further, light simulations of acoustic panels were performed, with and without bars. From those simulations, it can be concluded that good light distributions can be achieved behind such acoustic panels.