EP0230854A1 - Transparent panel forming a part of a room in an architectural construction - Google Patents

Abstract

The element (1) made of a transparent material comprises a plane face (10) and a face broken up into facets (2, 3, 4, 5, 6) which are arranged so as to limit prisms having parallel summit ridges (7, 8). Depending on the angle of incidence ( beta 2, beta 3) of parallel radiation (r1, r2, r3) striking one of the faces and depending on the construction parameters of the element and of the panel of which it forms part, the radiation is transmitted through the panel (p1, p2) or reflected from the side of the face (10) (re3). Depending on the choice, of the inclinations of the facets, the directions from the source (S) which are included between certain angular sectors are either reflected or transmitted depending on the point of impact of the ray, the facets oriented in one direction (2, 4, 6) exerting in this case a total reflection effect whereas the facets oriented in the other direction (3, 5) exert a transmission effect for the rays which strike them. <IMAGE>

Description

The present invention relates to a panel forming part of an enclosure in an architectural construction, having a face exposed in a determined orientation to light radiation, in particular solar, and consisting of one or more elements in one or more transparent materials, this or these elements each comprising at least one fragmented face formed of a set of facets inclined relative to the orientation of the panel, limiting prisms and exerting a selective action of total reflection or transmission on said radiation in function of the panel construction parameters: orientation of the element (s) and of the panel in space, number and thickness of the elements, number and position of the fragmented faces, refractive index of the material (s), angles of inclination, number, shape and dimension of the facets, thickness of the interstice (s) between the elements.

The construction of panels using glass plates of which one or both sides have a relief formed of facets limiting prisms is a technique already known in the construction of buildings and this technique has been used to measure in a certain way the penetration of light and / or heat rays into a space limited by an enclosure of which the panel constitutes one of the parts. Mention may in particular be made, as an exemplary embodiment in this field, of the patents US 3,393,034 (Imai), US 2,812,692 (Boyd), US 3,255,665 (Weiher) or FR 340 584 (Pressed Prism Plate Glass Co.). However, recent research in the area of construction with the aim of using the advantages of incident radiation in the best possible conditions while eliminating their drawbacks have led to new studies on the conditions in which inclined facets provided on a flat element of transparent material exert a selective action of reflection total or transmission on incident radiation. Thus, American patent US 4,540,241 by the same applicant proposes a panel construction using in a more systematic way than before the properties of such facets.

The purpose of the present invention is to improve and bring a new development to the panels already known so as to allow the construction of enclosures which, studied according to the geographical location and the climate prevailing at the place where the panels must be installed, carry out a metering and an adjustment as meticulous as possible of the transmission of the luminous and calorific radiations striking the panel, taking into account the fact that these radiations vary in intensity and structure during the days and the seasons.

For this purpose, the panel according to the invention which, by the selective action of the facets divides the solid angle of 180 ° encompassing all the directions of the beams of parallel rays striking the said exposed face, in distinct angular sectors in which the beams incidents are, for a first type of sector transmitted completely, for a second type of sector returned completely, and, if necessary, for a third type of sector partially transmitted and partially returned according to the angle and the point of incidence of the rays on the exposed side, allows by the choice of its construction parameters to determine the number, the relative positions, the limits of the angular sectors of each of these types and even, as regards certain sectors of the third type, the proportion of the transmitted and reflected beams. The angular distribution of the sectors thus determined is identical for all the regions of the panel.

A large choice of possibilities as for the angular distribution of the sectors, is allowed by the diversity of structure of the prisms as for the number of facets, with the value of the angle with the tops of the prisms which they limit and other parameters of construction, and by the fact that each of the facets is determined so as to be able to be at the origin of several types of trajectories of direct radiation from the source inside the panel, each of them inducing at least three types of trajectories of these rays , one of the types of trajectories leading to a return of said rays to the source side, the type of trajectory leading to a direct transmission, i.e. without prior reflection, of these rays and one of the types of trajectories leading to an indirect reflection, i.e. after one or more preliminary reflections, of these rays. Thus, a panel made entirely of transparent material can be configured so as to operate a very finely differentiated selection of the incident beams in three-dimensional space according to their angles of incidence.

The choice of the values of the construction parameters is made as a function of a part of the set of positions in the said solid angle of 180 ° which the source occupies during a complete cycle, i.e. especially the portion of the solid angle of 180 ° that the sun travels during its daily and annual trajectory, on the other hand of all the sectors of the said three types that the panel determines in the whole of the solid angle of 180 ° and the orientations of this panel , so that it exerts a selective action determined on the incident radiation, according to the most important of these, direct radiation from the light source, and allows their return to the source side or their partial or total transmission at different times in a given sequence.

The invention also relates to an enclosure in an architectural construction comprising one or more panels of the type specified above.

It also relates to an element in one or more transparent materials comprising at least one fragmented face and intended to be incorporated into a panel as specified above.

Before proceeding to the detailed description of various embodiments of an element of the panel according to the invention, some general indications will be given on the possibilities offered by the structure of the panels which are the subject of the present invention.

First of all, since the basic phenomenon exploited is a selective action of total reflection or transmission exerted by facets formed on a constituent element of the panel, this element being entirely of transparent material, it is not necessary to add to the panel no other material such as reflective layer or opaque absorbent layer.

On the other hand, the constituent elements of the panel have a structure such that they can be produced in a completely rational manner, either by printing or molding according to conventional methods. either by finer processes using advanced technologies and using, for example, Float glass, the two kinds of methods can also be combined.

The panels made up of the elements that are the subject of the invention can serve, for example, as a roof, as a cover, as opaque planes on the facade or on the roof, as a wall that is permeable to radiation, in particular greenhouses, covered malls or windows or bays glazed. We will come back to the advantages of the different applications mentioned above.

• la fig. 1 est une vue en perspective coupée d'un élément de panneau en matière transparente,
• la fig. 2 est une vue en coupe d'un élément tel que celui de la fig. 1, montrant un premier exemple d'actions sélectives de réflexion totale et de trans­mission exercées par les facettes,
• la fig. 3 est une vue en coupe analogue à la fig. 2, montrant un autre exemple d'actions sélectives exercées par les facettes,
• la fig. 4 est une vue en perspective coupée d'une face ou d'une facette exerçant une action sélec­tive sur trois rayons situées dans des plans quelcon­ques,
• la fig. 5 est une vue en coupe analogue à la fig. 2, montrant la projection, sur le plan perpendiculaire à la face,de l'action exercée par les facettes sur un rayon situé hors de ce plan,
• les fig. 6 et 7 sont des graphes représentant de façon schématique les performances de l'élément considéré dans les fig. 1 à 5, en termes de distri­bution angulaire,
• la fig. 8 est une vue en perspective coupée d'un élément correspondant à une autre forme d'exé­cution,
• la fig. 9 est un graphe représentant de façon schématique les performances de l'élément considéré dans la fig. 8, en termes de distribution angulaire,
• la fig. 10 est une vue schématique se référant à une utilisation d'un panneau en tant que paroi,
• la fig. 11 est une graphe illustrant de façon schématique les variations de l'angle d'incidence d'un faisceau parallèle provenant du soleil sur le panneau de la fig. 10, au cours des heures et des saisons,
• la fig. 12 est une vue analogue à la fig. 10 montrant un panneau dont la position est proche de l'horizontale et inclinée ver l'ouest,
• la fig. 13 est un graphe analogue à celui de la fig. 11, et montrant les variations de l'angle d'incidence d'un faisceau parallèle provenant du soleil sur le panneau de la fig. 12, au cours des heures et des saisons.

We will now describe below by way of example two embodiments of elements of panels with fragmented faces, constituting embodiments of the invention. We will base this on the accompanying drawings, including:

• fig. 1 is a cut perspective view of a panel element made of transparent material,
• fig. 2 is a sectional view of an element such as that of FIG. 1, showing a first example of selective actions of total reflection and transmission exerted by the facets,
• fig. 3 is a sectional view similar to FIG. 2, showing another example of selective actions exerted by the facets,
• fig. 4 is a perspective view cut from a face or a facet exerting a selective action on three rays located in any planes,
• fig. 5 is a sectional view similar to FIG. 2, showing the projection, on the plane perpendicular to the face, of the action exerted by the facets on a radius located outside this plane,
• fig. 6 and 7 are graphs schematically representing the performance of the element considered in FIGS. 1 to 5, in terms of angular distribution,
• fig. 8 is a cut perspective view of an element corresponding to another embodiment,
• fig. 9 is a graph schematically representing the performance of the element considered in FIG. 8, in terms of angular distribution,
• fig. 10 is a schematic view referring to a use of a panel as a wall,
• fig. 11 is a graph schematically illustrating the variations in the angle of incidence of a parallel beam coming from the sun on the panel of FIG. 10, during the hours and seasons,
• fig. 12 is a view similar to FIG. 10 showing a panel whose position is close to the horizontal and inclined towards the west,
• fig. 13 is a graph similar to that of FIG. 11, and showing the variations in the angle of incidence of a parallel beam coming from the sun on the panel of FIG. 12, during the hours and seasons.

Let us now consider an element 1 (fig. 1) of a panel according to the invention. It is made up of a plate 1 made of a material having a refractive index n. This material can be one of the many known glasses, or if necessary a transparent plastic. In the examples which follow, it will be considered that the refractive index of the material of the element is of the order of n = 1.5. The element 1 has a flat face 10 which will constitute the face of the panel exposed to incident radiation. The other side of the panel is a fragmented face consisting of a series of facets 2, 3,4,5,6, etc. of rectangular shapes joined along edges 7, 8, etc. which are parallel to each other and parallel to the face 10 of the element. In addition, it will be assumed in this embodiment that all the facets 2,3,4,5,6 etc. are of the same shape and the same dimension, and that they are arranged symmetrically with respect to planes which are determined by perpendiculars to the face 10 and parallels to the edges 7, 8 etc. The different prisms formed by each pair of facets 2 and 3, 4 and 5, etc. are therefore symmetrical prisms, and for the understanding of the explanations which will follow it will be admitted that in a first variant the angle at the top of each prism, i.e. the dihedral angle between facets 2 and 3 or facets 4 and 5 is of the order of 106 °.

Let us now consider a light source S which has been represented in FIG. 1 at a finite distance from the face 10, but which could just as easily be located at infinity in any direction included in a plane perpendicular to the face 10 and parallel to the longitudinal edges 7, 8 etc. A ray r1 coming from the source S and striking the face 10 in a direction perpendicular to this face crosses it and strikes for example the facet 6 at a point P1. The angle of incidence alpha 1 of radius r1 on the facet 6 being less than the critical angle of the material, this radius is transmitted through the facet 6 and emerges after refraction in the direction given by the transmitted ray t1. Let us now consider a radius r2 from the same source, also contained in a plane perpendicular to the face 10 and parallel to the edges 7, 8 etc. but doing with the perpendicular to the face 10 a beta angle 2, so that it undergoes refraction by crossing the face 10 and strikes the facet 6 at a point P2. The refracted ray rʹ2 and the perpendicular to facet 6 at point P2 determine a plane pi 2 in which the transmitted ray t2 from point P2 of the refracted ray rʹ2 will be contained. The plane pi 2 is different from the plane perpendicular to the face 10 and containing the source S. On the other hand, the angle of incidence alpha 2 of the refracted ray rʹ2 with the perpendicular to the facet 6 at the point P2 is greater than the angle alpha 1. It will however be admitted that it still does not reach the critical angle, so that the radius t2 is indeed a transmitted radius. It is understood, however, that if we then consider a radius r3 having with respect to the perpendicular to the face 10 an inclination greater than the radius r2, but also originating from the source S and contained in the same plane as the rays r1 and r2, this ray r3 striking with an angle of incidence beta 3 the face 10 will be able to determine a refracted ray r fera3 which will make, at the point P3 where it strikes the facet 6, with the perpendicular at this point to the facet 6 an angle alpha 3 which will be greater than the critical angle if the beta 3 angle of incidence is large enough, i.e. in the order of 28 ° in this example. The facet 6 will have for the ray rʹ3 an action of total reflection and will cause the sending of a reflected ray re3 which will end up emerging through the face 10, after a certain number of reflections in the element. The plane pi 3 determined by the rays rʹ3 and re3 and in which is also contained the perpendicular to the facet 6 at the point P3 will also be a plane having an orientation different from that of the plane containing the rays r1, r2 and r3.

Of course, what has been explained above with regard to individual light rays r1, r2, r3 is also valid for any beam of parallel rays having one of the directions defined by r1, r2 or r3. On the other hand, beams of parallel radii contained in planes defined by the perpendicular to the face 10 and the parallel to the longitudinal edges of the element have so far been considered. In this embodiment, however, if we consider a beam of parallel rays of type r1, we see that, whatever the point of incidence of these rays on face 10, they will penetrate into the element without refraction and strike any of the facets 3,4,5,6 etc. at an angle less than the critical angle, so that they will emerge from the element in the form of transmitted rays t1 deflected either in one direction or in the other, in the direction in which the facets they pass through are inclined. It is understood on the other hand that, in other embodiments where the angle which the facets make with the face 10 would be greater than the critical angle of the material, these same radii r1, after having penetrated the element without refraction by side 10, would strike any facet 3,4,5,6 etc. at an angle greater than the critical angle, so that they would be reflected by this facet inside the element.

Let us return to our first embodiment, and now consider a beam of parallel rays contained in a section plane perpendicular to the longitudinal edges of element 1, the rays of this beam making with the perpendicular to face 10 a beta angle 4 Fig. 2 shows that, when the beta angle 4 increases, it reaches a value where the radii of the incident beam are no longer entirely transmitted, as was the case for rays r1, but where, after refraction and formation of rays rʹ4, they fall on one of the facets 2,4,6, etc. for example facet 2, striking it at points Pʹ4 where their angle of incidence alpha 4 relative to the perpendicular to the facet is greater than the critical angle. We see on the other hand that in the case represented in FIG. 2, this fact gives rise to two phenomena: on the one hand a part of the beam striking the facet 2 undergoes a first total reflection in the direction of the face 10, to be finally returned symmetrically to its direction of incidence after being reflected by facet 3, as indicated by the beam F4, and on the other hand part of the beam resulting from the first total reflection directly hits facet 3 and undergoes a new total reflection, so that it gives rise to the beam Fʹ4, which is then also returned towards the source side of the element 1. As for the rest of the parallel radiation r4 which, after refraction by the face 10 and formation of the rays rʹ4, hits facet 3, it has with respect to this facet an angle of incidence alpha fac4 which is less than the critical angle, so that it is refracted towards the side of the panel opposite the source and gives rise to the beam F .4.

Thus, for certain values of the angle of incidence, beta 4 on the face 10, the fragmentation of the face opposite to the face 10 has the effect of a selection action of the third type, i.e. a partial return and a partial transmission of the beam, according to the precise point of incidence of each ray on the face 10.

Fig. 3 shows a phenomenon of indirect transmission which appears for certain values of the inclination of the facets, for example for angles less than 116 ° to the vertices of symmetrical prisms when the refractive index of the transparent material is 1.5. In this figure, as in the previous ones, the angle at the top is 106 °.

Thus, if we consider incident rays not far from the horizontal, i.e. for which the beta 5 angle of incidence is close to 90 °, part of the refracted beam f5 strikes facets F3, F5, etc. and comes out of element 1 after a new refraction as seen in fʹ5, in fig. 3. However, the other part of the incident beam refracted inside the element 1 hits the facets F2, F4, F6, etc. and on these facets undergoes a total reflection, which returns it to the facets F3, F5, F7, etc. These transmit it and it emerges from element 1 in the form of a deflected beam f6. For these beams, there is an indirect transmission which will be called order 1, since it takes place after a single total reflection inside the element 1. The entire incident beam is therefore transmitted through the item 1.

Let us now consider all of the beams whose incident trajectories are either inside or outside the two reference planes perpendicular to the face 10 mentioned so far, i.e. the plane parallel to the longitudinal edges and the plane perpendicular to these edges. To emerge from the element, each of these beams must, after having penetrated through the face 10 and having followed a more or less long trajectory inside this element, strike either a facet or the face 10, at an angle less than the critical angle. As we now consider the angles of any incidence of beams coming from all directions in three-dimensional space, we must no longer simply take into account the critical angle of the material on said face or facet in one or the other reference plane , but more generally of the critical cone formed by the critical angles in the set of planes containing the normal to this facet. The type of trajectory traversed by a ray depends on its angle of incidence and if necessary on its point of incidence on the element. Consequently, to each type of trajectory corresponds an angular sector of incidences from which the beams are transmitted either by the face, or by the facet where this type of trajectory ends. The limits separating these angular sectors have a curvature deriving from the very shape of the cones and overlaps resulting from partial or total overlaps of the effects of these cones on the paths of the beams.

Figs. 4 and 5 show how the invention takes advantage of these critical cones and the limits which correspond to them. Fig. 4 shows in perspective cut three striking rays, from the interior of the element, the face or a facet, F1, at point P. The radius rʹ5, perpendicular to F, strikes F through the interior of the critical cone Cc, and is transmitted by F without refraction in t5. The radius rʹ6, striking F at an angle of incidence less than the critical angle, is transmitted with refraction by F at t6. The ray rʹ7, striking F at an angle of incidence greater than the critical angle, is reflected by F in the form of the reflected ray re7.

Fig. 5 shows an element of the same index and the same configuration as FIGS. 1, 2 and 3. She shows in section the critical cones Cca, Ccb, Ccc, Ccd respectively surrounding the normals N of face 10, facet 2, facet 3 and again of face 10. It also shows the projection on the perpendicular plane at the edges, of two possible paths A and B for two rays r8 and rʹ8 belonging to the same beam. These trajectories are located outside of said reference planes and are identical from the source to the point of reflection on the face 10 Pd. When the radius r8 penetrates the element at the point Pa and inside the cone Cca, the component of its angle of refraction in the plane perpendicular to the element and parallel to the edges is less than 42 °, but sufficiently close to this figure so that the radius r8 which has become re8 after having been successively reflected by facet 2 and facet 3, reaches face 10 at point Pd from the outside of the cone Ccd, i.e. making an angle of more than 42 ° with the normal to this face. This is explained by the fact that at this point Pd, the component of the trajectory in the other reference plane, i.e. the plane perpendicular to the edges is greater than at the point Pa. There is reflection of the radius which continues its course, that is to say along the trajectory A, i.e. symmetrically along the path from Pa to Pd, the ray first striking facet 4, ie along the path B in which the ray is reflected from point Pd towards facet 3, and is transmitted by the latter in the form of radius t8. We will name this type of transmission indirect transmission of order 2.

We note that the point of incidence of the radius r8 on the face 10 and the thickness of the element compared to the dimensions of the facets play a determining role as for the proportion of the rays of the same angle of incidence which follow one or the other trajectory.

Let us note on the one hand, that if one varies in a progressive way the angle of incidence of a beam of parallel rays, the passage from one sector to another, and therefore from a mode of selection to a other, is done suddenly when the beam trajectory crosses the virtual limit constituted by the surface of one or the other critical cone, and that, on the other hand, the sectors distributed in a given angular distribution, are separated by limit curves which correspond to continuous sequences of values of the angle of incidence on the face 10, and by limit points which correspond to values of the angle of incidence at which limit curves cross. We can therefore draw these curves and limit points in a graph representing the angles of incidence on the element by their azimuth and their elevation.

Fig. 6 shows such a graph where the x axis represents the incidences of 0 ° and 180 ° azimuths contained in the reference plane perpendicular to the face 10 and parallel to the edges, where the y axis represents the incidences of 90 ° azimuths and 270 ° contained in the reference plane perpendicular to the edges, and where the elevations form concentric circles, the circle L representing the elevations of 90 ° relative to the normal to the face 10. The central point C therefore corresponds to the angle of incidence normal to face 10, and whose azimuth and elevation are equal to 0 °. The curves and limit points separate in the solid angle of 180 ° from the incident radiation the angular sectors for which the selection actions are of different types. Fig. 6 shows all the limits corresponding to the actions of selection undergone by the beams first reaching facets 2, 4, 6 etc. tilted in one direction. These limits determine the angular distribution in seven sectors which corresponds to the particular embodiment considered in this example. These seven angular sectors have the following properties: the angular sector S1 includes beams whose rays, such r1 and r2 are transmitted through the element directly by the first facet 2, 4, 6, etc. let them strike; the angular sector S2 includes beams whose rays, after having been reflected by a facet 2, 4, 6, etc. are transmitted through the panel by a facet 3, 5, 7, etc .; the angular sector S3 includes beams whose rays after having been reflected by a facet 2, 4, 6, etc. towards a facet 3, 5, 7, etc. are returned to side 10, then retransmitted by side 10 on the source side; the angular sectors S4 and S5 include beams whose rays can, depending on the precise place where they strike a facet 2, 4, 6, etc., either be transmitted through the panel by a facet 3, 5, 7, etc. . after having been successively reflected by a first facet 2, 4, 6 etc. a facet 3, 5, 7, etc. and side 10, either be returned to side 10, and transmitted by the latter on the source side, after having been successively reflected by a first facet 2, 4, 6, etc., side 10, and a facet 3, 5, 7, etc., or even after having been successively reflected by the facets 2, 4, 6, etc. 3, 5, 7, etc. the face 10, and again the facets 2, 4, 6, etc., 3, 5, 7, etc .; finally, the angular sectors S6 and S7 include beams whose rays are finally returned to the source side, after a complex succession of internal reflections on the facets and the face 10.

We can establish a graph of the same kind to represent the curves and limit points corresponding to the phenomena undergone by the set of beams which first reach facets 3, 5, 7, etc. tilted in the other direction. This graph will be exactly symmetrical to that presented in fig. 6, since facets 3, 5, 7, etc. are symmetrical in facets 2, 4, 6, etc.

By combining these two graphs, we obtain in fig. 7 the complete graph representing the angular distribution determined by the element on the set of beams which strike it: the angular sector S1 includes beams of which all the rays are transmitted directly by the first facet 2, 4, 6, etc. or 3, 5, 7, etc. struck; the angular sectors S2 and Sʹ2 include beams whose rays are transmitted either by a facet 3, 5, 7, etc. after having been reflected by a facet 2, 4, 6, etc., or by a facet 2, 4, 6, etc. after having been reflected by a facet 3, 5, 7, etc .; sectors S3, Sʹ3, S6, Sʹ6, S7 and Sʹ7 include beams, part of the rays of which are finally returned by the element, after having been reflected twice or more by the facets or by the facets and the face 10, and whose other part of the rays is directly transmitted by the facet they strike; the angular sectors S8, S9, S10 and S11 include beams from which all the rays are finally returned by the element, after having been reflected twice or more by the facets or by the facets and the face 10; finally, the angular sectors S4 and S5 include beams, part of which is finally transmitted, and the other part finally returned, the proportion between these two parts varying according to the ratio between the thickness of the element and the dimension of the facets.

The layout of the limit curves and the size of the sectors naturally depends on the exact values of the parameters chosen. Thus, certain curves may, instead of crossing at two points, only touch each other by a single point, so that the amplitude of the encompassed sector is reduced to a single value of the angle of incidence, or be totally separate. Similarly, certain curves determined by different facets can be confused. In other embodiments, other curves or other deformations can be obtained: for example, in the case of an axymmetric prism, the curves are offset relative to the x axis.

The embodiment described so far included a planar face and opposite this planar face a fragmented face composed of a network of pairs of facets forming an angle greater than 90 ° between them and forming symmetrical prisms with parallel edges. However, in other embodiments, these different parameters may vary. The angle that the facets make between them can also be equal to or less than 90 °. The prisms may not be symmetrical, their two facets not having the same inclination relative to the face 10. Finally, each prism can have more than two facets.

Thus, fig. 8 shows by way of example a second embodiment. We consider an element 11 which is also a plate of transparent material, but whose structure differs from that of element 1. This element always has a flat face 20 which is the hidden side in the perspective representation of FIG. 8 and opposite this face 20, a face fragmented. However, it has two networks of facets, forming complex prisms with four facets. The first network is formed by parallel rows of pairs of facets whose edges are inclined in a direction relative to the face 20. The facets 21, 22, 23, 24, etc. form a row of this type, and the facets 31, 32, 33, 34, etc. a second row of this type. The second network is constituted by parallel rows of pairs of facets whose edges are inclined in the other direction relative to the face 20. For simplicity, we consider here the case where the edges of the prisms of the rows of the first type do with those of the prisms of the second type have an angle of 90 ° and have an equal inclination, of 45 ° relative to the face 20. Similarly, in each row, the facets of each couple make an angle of 90 ° between them.

The graph corresponding to this embodiment is very simple because, because the facets make 90 ° angles between them and the edges also make 90 ° angles between them, all the important limits are superimposed to give the four curves shown in fig. 9. These limits define seven angular sectors: sectors S1 and Sʹ1 include beams of which all the rays are directly or indirectly transmitted. Sectors S2, Sʹ2, Sʺ2 and S ‴ 2 include beams, part of the rays of which are transmitted indirectly by a facet after striking another facet of the same row, and the other part of which is returned to the side of the source after having been reflected by either two or four facets successively; the angular sector S3 includes the beams, all the rays of which are returned to the side of the source after having been reflected successively either by two or by four facets. Certain minor selection phenomena affecting certain rays which strike the facets near the apexes of the prism are not shown in FIG. 9.

In an element of this kind, the various constructive parameters, and therefore the angular distribution, can also be modified in large measures. Thus, as soon as the angles cease to be 90 °, the limits separating the different types of sectors cease to overlap, and the graph shows other curves and limit points. Of course, it is also possible here to imagine other distributions of facets in a fragmented face of an element according to the invention. For example, there may be three-faceted prisms, five facets, etc. Complex prisms can also be asymmetrical.

This embodiment allows the element to return in a particularly effective way direct radiation coming for example from the sun when the element being oriented so as to be perpendicular to the sun at its zenith, the trajectory of this one is translated on the corresponding graph by the diameter located in the middle position of sector S3.

Two neighboring execution examples will show how certain modifications to the configuration of the element allow this performance to be varied.

A first example of modification consists in inclining by a few degrees the plane in which the edges formed by the facets 21 and 22, 31 and 32 of FIG. 8 are inscribed, and so on, so that this plane is not more perpendicular to the face 20. The limit curves indicated in FIG. 9 move as much, giving the sector 3 a curved, asymmetrical shape. The trajectory, for example solar, for which the element returns the direct rays most effectively then translates on the graph by an arc crossing the sector S3 in its length, the element no longer being completely perpendicular to the source at its zenith.

A second example of modification consists in flattening in FIG. 8 the rows of facets whose edges are oriented in one direction, for example the rows 21, 22, 23, 24, etc., 31, 32, 33, 34, etc. and so on, while retaining the faceted fragmentation of the rows whose edges are oriented in the other direction. We thus obtain complex prisms with three facets. The sector S3 of fig. 9 then roughly takes the form of a triangle with curved edges, allowing a very gradual variation in the selection performance according to the seasons.

Panels constituting enclosure parts in an architectural construction may consist of one or more elements such as the elements according to the invention. In the case where only one element is used, the fragmented face can be, in certain applications, exposed to radiation as well as the planar face, for example in the case where there are two sources of radiation, a on each side of the panel.

On the other hand, instead of the element having a flat face and a fragmented face, it can also have two fragmented faces.

Another interesting embodiment of the panels according to the invention consists in adding a complementary element to the main element which we have chosen to use.

An additional element is an element comprising a flat face and a face fragmented into facets, the positions of these faces being reversed with respect to those which they occupy in a main element. Its fragmented face is juxtaposed facet to facet to that of a main element, the prisms of the two elements having identical angles, and the radiations which come from this main element penetrate it by its facets. Its main function is to add to the flat face of the main element another parallel flat face. It thus allows, on the one hand to subject the radiation passing through the two elements by direct transmission to a refraction at their exit from these elements, complementary to that undergone by penetrating therein so that the rays finally transmitted by the pair of elements emerge in the same direction as when they entered it (so that the distortions of the transmitted images, and the diffractions of the transmitted radiation, are reduced to a minimum), and on the other hand to subject certain radiation passing through the 'principal element by indirect transmissions an additional total reflection, so as to return them, by making them cross again the principal element, towards their source medium, thus increasing the proportion of the radiations finally returned by the panel.

This second action of the complementary element makes it possible to increase the number of useful values of the angles at the vertices of the prisms of the element main, including more closed angles, the range being able to go theoretically (if this prism is symmetrical and for a critical angle of 42 °) from 142 ° to 12 ° (value from which there is no longer direct transmissions in a symmetrical prism). In practice, sufficiently different values of 142 ° and 12 ° will be chosen so that there are enough incident beams belonging to the sectors of each of the desired types.

The gap between the fragmented faces of the two elements is of constant thickness. However, it will be possible by a sufficiently large interstice to obtain certain changes in trajectories.

This gap will be occupied by air or, if necessary, in certain constructions, may be kept empty. It could also, as a variant, be occupied by a transparent medium having a refractive index sufficiently different from the index of the material constituting the elements to obtain the desired total reflection phenomena.

It should be emphasized that the main element and the complementary element being arranged symmetrically to each other, they can exchange their roles for radiation traveling in opposite directions, i.e. from the protected environment.

Elements as described previously similar or complementary, identical or different can be superimposed to form panels according to the invention. One can also provide for the use of several elements placed edge to edge so as to constitute a wall or a bay window. However, in certain cases, it may also be advantageous to provide parts of partitions or parts of enclosures made up of several elements according to the invention placed side by side, without however being in the same plane, the values of the angles which such elements make between them must then be sufficiently different from 180 ° so that the optical interaction between these elements modifies the overall angular distribution that the panel determines in the 180 ° solid angle of the incident radiation, while maintaining a sufficient balance between the various types of sectors of this angular distribution.

It is therefore understood that the invention makes it possible to vary the angular distribution of the panels also as a function of parameters other than those specific to the prism itself. On the one hand, the proximity of the many repetitive prisms forming the element, and on the other hand the relationship between the depth of the reliefs and the thickness of the element (parameter determining the importance of the internal passages between the prisms), in turn modify the repertoire of trajectories. Certain radiations can indeed, according to their angle of incidence, pass from a given prism to a neighboring prism, in certain cases by the interior of the transparent material (by total reflection on the faces 10 or 20), in others case from the outside of the transparent material (by transmission by a facet of a prism, then recovery by a facet of another prism). In these two cases, trajectories must be considered, traversing and grouping more than one prism.

It should also be noted that in certain embodiments, the extension of certain facets in the form of slots inside the element makes it possible to usefully increase the surface of these facets, as in particular in the case of the most narrow asymmetric prisms.

The invention also makes it possible to vary the angular distribution as a function of certain combinations of elements. If we bring two or more elements together, either by juxtaposing them by their faces (fragmented faces and / or planar faces) or by joining them by their edges at angles sufficiently different from 180 °, the repertoire of trajectories is further modified, the fact that the radiation transmitted by an element is directly received, then selected, by any other element juxtaposed to it face to face, and the fact that some of the radiation transmitted or returned by an element are received, then selected, by any attached element side by side at a suitable angle. In these two cases, trajectories must be considered, covering and grouping more than one element. A particular case of combination of elements is that of a panel comprising four fragmented faces nested in pairs and where the planes not parallel to the panel and parallel to each other in which the said edges are contained form two families of planes, containing respectively the edges of one of the interfaces and those of the other, and intersect at an angle different from 0 °.

It is, finally, possible to obtain a combined angular distribution by taking advantage of the interactions that may appear between several panels, some receiving the radiation transmitted or returned by the others (reciprocally or not), either so as to obtain a better performance. selective overall, either so as to deflect or conduct certain radiation along trajectories and over distances exceeding the order of magnitude of a panel.

Generally, the configuration parameters of the elements are determined in such a way that the angular distribution of the solid angle of 180 ° of the incident radiation which corresponds to the panel is positioned with respect to the complete cycle of the source (i.e. for example to the portion of said solid angle traversed by the sun during the hours and seasons) so as to be superimposed thereon, in the exact manner necessary, in each case, for the performance of the functions of the panel.

More precisely, in the case of elements with simple prisms, the parameters must have values determined so that, for each of these prisms taken individually, of all the beams coming from the solid angle of 180 ° of the incident radiation which penetrate this prism by the flat face and which are ultimately transmitted entirely or in part by the element to which this prism belongs, some are either by indirect transmissions of order 1 and direct, or by indirect transmissions of order 2 and direct, or again by the three at the same time. It follows that, for example, for a simple symmetrical prism, if the critical angle is equal to 42 ° (typical figure for a building glass), the useful limit values of the angle made by the two facets between them are are between 142 ° and 12 °. In the case of elements with complex prisms (more than two facets per prism) due to the fact that each pair of facets behaves, with the planar face thereof, like a "simple" prism (with the difference that its edge does not is not parallel to the plane face), there exist, for each complex prism taken individually, more than a couple of curves by types of trajectories. It follows that the action of the element depends on the combination particular of pairs of facets that the complex prism realizes, more than values proper to one or the other of these couples.

The panels according to the invention will be used by the construction of enclosures in various architectural achievements. The wide variety of performance of these panels due to the different forms of execution and the large choice of parameters for each of them will allow them to be installed in various ways, horizontally, sloping, or vertically, to orient them also differently in relation to the route from the sun or at the source, either that they protect a room located inside a building or an open space.

Thus, fig.10 and 11 give an example relating to the case of a panel P which is located in an enclosure while being oriented facing south in a position slightly inclined relative to the vertical. In fig. 10 there is shown in a diagram the panel P and the directions Se and So and Sh from sun to noon, respectively to the summer solstice, to the equinox and to the winter solstice. The direction of the perpendicular to the panel P being indicated by the straight line p, we have noted in fig. 10 the angles between the directions of the perpendicular and the three solar positions by the indications beta _e , beta _o , and beta _h . In a graph allowing to locate the orientations of a source compared to the perpendicular to the panel, such as it is represented in fig. 11, we see that a horizontal line H represents the direction of the horizon identified with respect to the perpendicular to the panel and therefore indicates by the ordinate pi the inclination of this perpendicular with respect to the horizontal. The daily trajectories of the sun at three dates of the year indicated above can be easily plotted on this graph as seen in fig. 11 so that, if one superimposes the graph of FIG. 11 the graph giving the performance of the panel P in a manner analogous to that which has been indicated in connection with FIGS. 7 and 9, an image is immediately obtained of how the panel reacts to the impact of the sun's rays during a day and during the year. Regarding the panels used as roofs, figs. 12 and 13 show the performance obtained when using a panel P as a roof element whose perpendicular is contained in a vertical plane oriented east-west and is inclined towards the west. The directions of the sun at the three dates of the year already shown in fig. 10 are again shown in FIG. 12 and the corresponding paths of the sun identified with respect to the perpendicular to the panel in a graph of the same kind as that of FIG. 11 are shown in FIG. 13. It is easy to see the multiple possibilities opened up by the use of elements of the type described for making roofing panels or wall panels making it possible to take advantage of the external conditions in the best possible way. penetration of light and heat into a space protected by one or more of them. In hot climate, as in cold climate, one obtains an extremely marked thermal advantage by having the possibility of letting thermal radiation penetrate in the protected space at the time of the year when the climatic conditions require it, i.e. in winter, when at the time of the year when the elevation and the azimuth of the sun reach values which correspond to the maximum of sunshine, the radiation pa Rallels coming from the sun can be understood in a sector for which the performance of the panel is the return of radiation on the source side. In this regard, an interesting possibility consists in the fact that the panels can be configured so as to redirect certain incident beams directly towards the source, which can be useful for example to avoid effects of reflection of solar rays towards the ground at the foot of the buildings.

With regard to the use on roofs, the panel described provides an elegant and inexpensive solution to the problem of overhead lighting of industrial, commercial, cultural or other surfaces which require a light supply whose stability, homogeneity and distribution are controlled. It allows the creation of entirely transparent covers controlling the transfer of incident beams according to both their contribution in lighting and in heating. This solution can gradually replace the use of shed blankets, a solution which is known to be bulky and structurally complicated, while having performances which have never been entirely satisfactory.

The elements and panels described can also be used as covers for opaque planes, either in facades or in roofs. Thus, many opaque planes, such as lighters, curtain facades benefit from being covered with the panel described. Indeed, during hot periods of the year, and / or the day, these plans can be subjected to an intense heating which often is harmful to the structure itself and which moreover has an unfavorable effect on the interior of the building. The coating structures of this kind with one or more elements as described above makes it possible to maximize the heating of the plans in cold periods and to minimize it in hot periods, therefore to reduce the costs of insulation and air conditioning of the building. Facades made entirely of glass can therefore be provided, with both climatic, aesthetic and cost advantages.

In general, we know that we are always trying to protect certain private or public spaces with transparent walls and / or covers. However, these achievements have, until now, come up against the greenhouse effect which is unbearable in hot weather and often requires costly air conditioning installations and structures and entailing significant service costs, and a loss of brightness and in winter heat. The panels described provide a passive solution to this problem, requiring neither blinds nor active air conditioning. The space protected by panels of this kind can fully benefit in the cold period from the greenhouse effect while avoiding it entirely in hot periods and this without modifying the installation between the two periods.

The elements and panels described will therefore be useful in the creation of atria, covered malls or other public or private spaces with transparent walls and covers.

Finally, they can of course also find an application in greenhouse construction.

In the cases where one seeks to use the greenhouse effect to the maximum and not to preserve it, the panels described can also be interesting by the fact that they can function in both meaning. Thus, a space protected by transparent walls can be configured thanks to the panels described so as to retain inside this space radiation which would tend to escape, whether it is solar radiation which would otherwise pass through the greenhouse from side to side or whether it is radiation emanating in a cold or nocturnal period from an artificial source located in the protected space. In addition, the transparent walls can be designed so that radiation from the outside is also used in the best climatic and light conditions.

Claims (12)

1. Panel forming part of an enclosure in an architectural construction, having a face exposed in a determined orientation to light radiation, in particular solar, and consisting of one or more elements in one or more transparent materials, this or these elements each comprising at least one fragmented face formed of a set of facets inclined relative to the orientation of the panel, limiting prisms and exerting a selective action of total reflection or transmission on said radiation depending on the construction parameters of the panel: orientation of the element (s) and of the panel in space, number and thickness of the elements, number and position of the fragmented faces, refractive index of the material (s), angle of inclination, number, shape and dimension of the facets, thickness of the gap (s) between the elements, characterized in that the values of said parameters are determined so that, due to the selective action of s facets, the solid angle of 180 ° which encompasses all the directions of the beams of parallel rays striking the said exposed face is divided into distinct angular sectors in which the incident beams are, for a first type of sector transmitted completely, for a second type of sector returned completely, and for a third type of sector partially transmitted and partially returned according to the point of incidence of the rays on the exposed face, the said angular sectors having between them limits formed by continuous sequences of angles of incidence . 2. Panel according to claim 1, characterized in that the values of the parameters are chosen in such a way that the element induced for the incident rays at least three types of trajectories, one of which results in a return of rays from the side of the source, another to a direct transmission, without total reflection, through the panel, and a third to an indirect transmission, after one or more total reflections through the panel. 3. Panel according to claim 1, characterized in that the values of said parameters are determined both according to the set of positions occupied by the source, in particular the sun, during a complete cycle, in the said solid angle of 180 °, according to the orientations of the panel, and according to the distribution of the said angular sectors which is necessary so that the direct radiation of the source is returned or transmitted or if necessary partially returned and partially transmitted to different moments, according to a determined sequence, each of the facets being capable of being at the origin of trajectories of the said three types inside the panel for the direct radiation of the source. 4. Panel according to claims 1 to 3, characterized in that at least one of the said elements is a monolithic element in the form of a flat plate, one front face of which is planar, and forms the said face exposed to radiation, while the 'other front face is a fragmented face in which the longitudinal edges of the prisms are parallel to each other and parallel to said exposed face, and in that the determination of the parameters is such that in the said monolithic elements each prism taken individually gives rise to types of trajectories such that, of all the beams coming from the solid angle of 180 ° of the incident radiation which penetrate this prism by the planar face, there are, at least, which are ultimately transmitted by this element, either by direct transmissions and by indirect transmissions preceded by total reflection, or by direct transmissions and by indirect transmissions preceded by successive total reflections on two facets and the flat face or by these three types of transmission together. 5. Panel according to claim 4, characterized in that the structure of said monolithic element is such that the angles at the apex of the symmetrical prisms all have the same value between two limits which depend on the refractive index of the material and which, for a material having an index n = 1.5 are 142 ° and 12 °. 6. Panel according to claims 1 and 3, characterized in that at least part of the facets of at least one fragmented face has a secondary structure formed of a row of secondary facets so that the prisms have on at least one from their faces a relief structure of secondary prisms. 7. Enclosure in an architectural construction, characterized in that it comprises a series of panels according to any one of claims 1 to 6 juxtaposed by their edges and whose orientations are different. 8. Panel according to any one of claims 3 to 7, characterized in that said monolithic element is associated with a complementary element whose prisms are nested between those of the element monolithic so that the rays transmitted directly penetrate into the interior space of the enclosure without angular deviation. 9. Panel according to claims 3 to 8, characterized in that it comprises four fragmented faces fitted two by two, and in that the planes not parallel to the panel and parallel to each other in which the said edges are contained, form two families planes containing respectively the edges of one of the interfaces and those of the other, and in that these families of planes form between them an angle different from 0 °. 10. Panel according to any one of claims 1 to 9, characterized in that the enclosure part in which it is incorporated is a wall. 11. Panel according to any one of claims 1 to 9, characterized in that the enclosure part in which the panel is incorporated is a ceiling or a roof. 12. element for panel according to claim 1 in one or more transparent materials, of planar shape, having at least one fragmented face formed of a set of facets inclined with respect to the orientation of the panel, limiting prisms and exerting an action selective total reflection or transmission on incident light and / or heat radiation, depending on the construction parameters of the element: refractive index of the material (s), number, shape, dimension and inclination of the facets, number and arrangement of the fragmented face or faces, thickness of the element; this selective action of the facets dividing the angle of 180 ° which encompasses all possible angles of incidence of beams of parallel rays striking the element in distinct angular sectors in which the incident beams are, for a first type of sector transmitted completely, for a second type of sector returned completely and, where appropriate, for a third type of sector partially transmitted and partially returned according to the point of incidence of the rays, the said angular sectors being separated by limits formed by continuous sequences of angles of incidence, characterized in that the choice of the values of the said parameters determines the number, the location and the limits of the said angular sectors of each type and must allow at least three types of trajectories of the rays inside the panel: one of the types of trajectories leading to a return of the rays on the side of the source, the type of trajectories leading to a direct transmission of the rays, i.e. . without total prior reflection and one of the types of trajectories leading to an indirect transmission of rays, i.e. after one or more preliminary reflections.

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