EP3073187B1 - Elongated lighting emitting diode and shifted diopter - Google Patents

Description

The present invention relates to the technical field of lighting using light emitting diode (LED) light-emitting diode (LED) sources. The invention relates more particularly to so-called linear LED lighting devices intended to be a substitute for lighting systems using fluorescent linear tubes with mercury vapor or other.

Fluorescent tube lighting such as, for example, used inside industrial buildings, especially in storage warehouses, implements luminaires fixed in height, and aligned to illuminate spans. Each luminaire then comprises one, two or three parallel linear fluorescent tubes. These inexpensive luminaires actually make it possible to produce light, but they do not make it possible to obtain satisfactory illumination at ground level or in a volume between the ground and a height of two meters, given the height at which they are generally located. , from 4 m to about ten meters and how the tubes emit light on their entire periphery. Moreover, these luminaires do not make it possible to obtain an optimized electrical energy consumption and induce disturbances of the power supply networks to which they are connected because of their mode of operation and the systems used when they are switched on.

With the development of light-emitting diodes, linear fluorescent tube luminaires are replaced by linear luminaires with light-emitting diodes. In order to ensure quality ground lighting, when the luminaire is located at a great height, it is proposed to associate each diode with an individual optical system, said secondary lens which focuses and focuses the light, for example in a cone having an apex angle of about 20 ° to 30 °, so as to obtain the desired floor lighting.

However, the implementation of individual optical systems associated with each diode greatly increased the manufacturing cost of the luminaire which can be prohibitive for lighting in industrial environment in particular. This type of lighting device is shown in the document US 2010/0250309 A1 . Moreover, in some implementation configuration it is not always necessary to illuminate the ground just below and in the axis of the luminaire but it may be desirable to illuminate an area located on the side, shifted laterally relative to to the area directly above and in line with the luminaire.

It has therefore emerged the need for a new type of linear lighting device adapted to provide satisfactory lighting, offset from the axis of the luminaire to from a great height while having a manufacturing cost much lower than that of the luminaires comprising an optical system of concentration of the light associated with each light emitting diode.

• un corps allongé comprenant au moins une surface de réception d'au moins un substrat portant une source linéaire de lumière comprenant au moins une rangée de diodes électroluminescentes alignées selon un axe longitudinal du corps et délimitant, en partie au moins, au moins une chambre d'éclairage linéaire allongée dans laquelle la rangée de diodes est située,
• un capot linéaire allongé fermant en partie au moins la chambre d'éclairage.

Selon l'invention le capot forme, en relation avec la source linéaire, une lentille linéaire, au moins translucide, d'axe longitudinal parallèle à l'axe longitudinal du corps, avec une face externe d'émission de la lumière et une face interne de réception de la lumière des diodes, dont la face d'émission, vue en section droite transversale, possède une forme convexe, et dont la face de réception, vue en section droite transversale, comprend :

• un dioptre médial convexe décalé qui définit avec la face externe une lentille médiale biconvexe dont l'axe optique est décalé latéralement par rapport à un plan sagittal S,
• d'un coté du dioptre médial, un premier prisme latéral qui est adjacent au dioptre médial,
• de l'autre coté du dioptre médial, une série de prismes parallèles au premier prisme qui comprend au moins un deuxième prisme latéral et un troisième prisme latéral, le deuxième prisme latéral étant adjacent au dioptre médial et au troisième prisme latéral,
• chaque prisme latéral possédant une face médiale et une face latérale en partie au moins planes se raccordant au niveau d'un sommet du prisme correspondant, les prismes latéraux présentant chacun une hauteur, mesurée entre le sommet du prisme correspondant et la face externe, la hauteur du deuxième prisme latéral étant supérieure ou égale à l'épaisseur e de la lentille médiale mesurée entre le sommet du dioptre médial et la face externe.

In order to achieve this objective, the invention relates to a linear lighting device with light-emitting diodes comprising at least:

• an elongated body comprising at least one receiving surface of at least one substrate carrying a linear light source comprising at least one row of light-emitting diodes aligned along a longitudinal axis of the body and delimiting, in part at least, at least one chamber of elongated linear illumination in which the row of diodes is located,
• an elongate linear hood partially closing at least the lighting chamber.

According to the invention the hood forms, in relation to the linear source, a linear lens, at least translucent, with a longitudinal axis parallel to the longitudinal axis of the body, with an outer surface of light emission and an inner face receiving the light of the diodes, whose transmission face, seen in transverse cross section, has a convex shape, and whose receiving face, seen in cross section, comprises:

• an offset convex medial diopter which defines, with the external face, a biconvex medial lens whose optical axis is offset laterally with respect to a sagittal plane S,
• on one side of the medial diopter, a first lateral prism that is adjacent to the medial diopter,
• on the other side of the medial diopter, a series of prisms parallel to the first prism that includes at least a second lateral prism and a third lateral prism, the second lateral prism being adjacent to the medial diopter and the third lateral prism,
• each lateral prism having a medial side and a lateral side at least at least planar connecting at a vertex of the corresponding prism, the lateral prisms each having a height, measured between the apex of the corresponding prism and the outer face, the height the second lateral prism being greater than or equal to the thickness e of the medial lens measured between the vertex of the medial diopter and the external face.

The implementation of such a linear optic provides a lateral illumination lobe offset from the sagittal plane S of symmetry of the outer face of the hood. The Medial lens works to collimate light in a narrow angular sector centered on the optical axis of the lens that forms an acute angle with the sagittal plane.

In addition, the lateral prisms work in total internal reflection so as to reflect the light in the same direction as the medial lens.

Thus, the implementation, with each light source comprising at least one row of light-emitting diodes, of such a linear lens makes it possible to obtain for each light-emitting diode a lighting cone having in a plane transverse to the axis of the light emitting diode. alignment of the diodes an acute apex angle and, for example, between 10 ° and 30 ° and whose axis forms an acute angle with the sagittal plane. The lighting device according to the invention then makes it possible to provide a laterally satisfactory offset illumination even if it is located at a high height, for example greater than 5 meters and of the order of ten meters. This without the need to implement at each light emitting diode a so-called secondary lens, ensuring a conditioning light emitted by the diode. The luminaire according to the invention can therefore be used in high-level logistics racks but also especially in supermarkets and hypermarkets when the spokes are not located on each side of the aisle but only on one side as is the case. in a corridor at the back of the store.

The linear lens according to the invention formed of the medial lens and lateral prisms concentrates more than 90% and of the order of 95% of the light emitted by each diode in a cone centered on the optical axis of the lens.

Generally, a light-emitting diode comprises a semiconductor wafer which, when subjected to a suitable potential difference, emits a blue light radiation most often blue which is converted into white light or other by a layer of phosphors covered, directly or associated at a silicone thickness, at least a translucent and generally transparent coating forming a primary lens which comprises an outer emitting face of the light generated by the diode. The primary lens of the diode most often emits light on a half-sphere. The linear lens according to the invention allows, without individual secondary lens, to concentrate the light emitted by the lighting device in a direction inclined relative to the sagittal plane. Thus, according to a preferred but not strictly necessary feature of the invention, each light-emitting diode of the device lighting is devoid of individual secondary lens of light concentration.

Within the meaning of the invention, a material or an object is translucent if it allows the light coming from a reception face to pass towards an emission face and beyond this without the elements situated on the the receiving face are visible, clearly distinguishable or identifiable. Still within the meaning of the invention, a material or an object is transparent if it allows the light coming from a reception face to pass towards an emission face and beyond this and the elements situated on the side of the receiving face are perfectly visible, clearly distinguishable or identifiable. Thus, an at least translucent object or material is an object or material capable of having one or more gradations in the way in which it passes light or diffuses it between what would describe it as translucent and what would describe it as transparent.

In the sense of the invention, the sagittal plane is a plane substantially parallel to the longitudinal axis of the row of diodes and parallel to the emission axes of the light emitting diodes or primary lenses thereof. According to the invention, the sagittal plane is furthermore a plane of symmetry of the emission face of the linear lens.

According to one characteristic of the invention, the center of curvature of the medial diopter is situated on a plane forming with the sagittal plane an angle of between 10 ° and 45 °, in absolute value. This characteristic makes it possible to obtain an illumination lobe centered on a plane making an angle between 10 ° and 45 °, in absolute value, with the sagittal plane.

According to another characteristic of the invention, the medial diopter extends over an angular sector delimited by two normal planes on the outer face which form an angle of between 60 ° and 100 ° with each other.

According to one characteristic of the invention, the radius of curvature Rd of the medial diopter satisfies 0.11 R ≤ Rd ≤ 0.20 R where R is the radius of curvature of the emission face, also called external face.

According to another characteristic of the invention, the plane portions of the lateral and medial faces of the same lateral prism form an angle of between 15 ° and 60 °.

• le rayon de courbure R de la face externe est compris entre 13 mm et 30 mm,
• l'épaisseur e de la lentille médiale vérifie 0,15 R ≤ e ≤ 0,24 R
• la hauteur H₁ du premier prisme vérifie 0,11 R ≤ H₁ ≤ 0,27 R,
• la hauteur H₂ du deuxième prisme vérifie 0,15 R ≤ H₂ ≤ 0,24 R,
• la hauteur H₃ du troisième prisme vérifie 0,11 R ≤ H₃ ≤ 0,20 R.

According to one characteristic of the invention:

• the radius of curvature R of the external face is between 13 mm and 30 mm,
• the thickness e of the medial lens satisfies 0.15 R ≤ e ≤ 0.24 R
• the height H ₁ of the first prism satisfies 0.11 R ≤ H ₁ ≤ 0.27 R,
• the height H ₂ of the second prism satisfies 0.15 R ≤ H ₂ ≤ 0.24 R,
• the height H ₃ of the third prism satisfies 0.11 R ≤ H ₃ ≤ 0.20 R.

• le rayon de courbure de la face externe est compris entre 24 mm et 28 mm,
• la hauteur H₁ du premier prisme est comprise entre 3 mm et 7 mm,
• la hauteur H₂ du deuxième prisme est comprise entre 4 mm et 6 mm,
• la hauteur H₃ du troisième prisme est comprise entre 3 mm et 5 mm,
• l'épaisseur e de la lentille médiale est comprise entre 4 mm et 6 mm.

According to another characteristic of the invention:

• the radius of curvature of the external face is between 24 mm and 28 mm,
• the height H ₁ of the first prism is between 3 mm and 7 mm,
• the height H ₂ of the second prism is between 4 mm and 6 mm,
• the height H ₃ of the third prism is between 3 mm and 5 mm,
• the thickness e of the medial lens is between 4 mm and 6 mm.

According to a feature of the invention for increasing the concentration of light in the preferred illumination zone, the series of prisms comprises a fourth lateral prism parallel to the other lateral prisms and adjacent to the third lateral prism being located opposite of the second lateral prism with respect to the third lateral prism, the fourth lateral prism having a medial side and a partially flat at least lateral face connecting at a vertex of the fourth lateral prism.

According to a variant of this characteristic, the height H ₄ of the fourth prism, measured between the apex of the fourth prism and the external face, satisfies the following relationship 0.07 R ≤ H ₄ ≤ 0.12 R where R is the radius of curvature of the outer face.

According to another variant of this characteristic, the height H ₄ of the fourth prism, measured between the apex of the fourth prism and the outer face, is between 2 mm and 3 mm.

According to yet another variant of this characteristic, the flat portion of the lateral face of the fourth prism forms with the sagittal plane an angle of between 10 ° and 45 ° in absolute value.

• la partie plane de la face médiale de chaque prisme forme avec le plan sagittal un angle compris entre 0° et 45° en valeur absolue,
• la partie plane de la face latérale de chaque prisme formant avec le plan sagittal S un angle compris entre 0° et 80° en valeur absolue.

According to one characteristic of the invention:

• the flat part of the medial face of each prism forms with the sagittal plane an angle of between 0 ° and 45 ° in absolute value,
• the flat part of the lateral face of each prism forming with the sagittal plane S an angle between 0 ° and 80 ° in absolute value.

• la partie plane de la face latérale du premier prisme forme avec le plan sagittal S un angle compris entre 45° et 80° en valeur absolue,
• la partie plane de la face latérale du deuxième prisme forme avec le plan sagittal S un angle compris entre 5° et 40° en valeur absolue,
• la partie plane de la face latérale du troisième prisme forme avec le plan sagittal S un angle compris entre 30° et 60° en valeur absolue.

According to a variant of this characteristic:

• the flat part of the lateral face of the first prism forms with the sagittal plane S an angle of between 45 ° and 80 ° in absolute value,
• the flat part of the lateral face of the second prism forms with the sagittal plane S an angle of between 5 ° and 40 ° in absolute value,
• the flat part of the lateral face of the third prism forms with the sagittal plane S an angle of between 30 ° and 60 ° in absolute value.

According to one characteristic of the invention, each diode comprises a primary lens associated with a convex or plane emission face and the apex of each emission face of each diode is located at a distance d from the vertex of the lower external face or equal to 0.74 R and preferably less than or equal to 0.31 R, where R is the radius of curvature of the outer face.

According to another characteristic of the invention, the apex of the primary lens of each diode is located between a plane passing the points of the extreme prisms farthest from the apex of the outer face and a plane tangent to the apex of the outer face. This feature increases the amount of light redirected to the preferred lighting area.

According to another characteristic of the invention, the body comprises in the lighting chamber, in relation to each longitudinal row of light-emitting diodes, two planar reflectors extending parallel to the longitudinal axis of the body being located on both sides of the body. water from the receiving surface and forming, with each other, an angle of between 100 ° and 170 °. The use of such reflectors makes it possible to increase the luminous efficiency of the lighting device according to the invention.

According to a variant of this characteristic, the apex of the primary lens of each diode is located between a plane passing through the lateral edges of the reflectors and a plane tangent to the top of the central diopter. This variant makes it possible to optimize the concentration of light by the linear lens.

According to one characteristic of the invention, the body is made of metal. Such a metal body ensures good evacuation of the heat generated by the light emitting diodes and their power supply. Preferably, the body is made in the form of a profile obtained by means of a die without this excluding the possibility of making the body in any other suitable manner, for example by folding.

According to one characteristic of the invention, the linear source of light comprises several longitudinal rows of parallel light-emitting diodes.

Of course, the different features, variants and embodiments of the lighting device according to the invention can be associated with each other in various combinations to the extent that they are not incompatible or exclusive of each other.

• La figure 1 est une perspective schématique en vue partiellement éclatée d'un dispositif d'éclairage selon l'invention.
• La figure 2 est une coupe transversale du dispositif d'éclairage illustré à la figure 1.

Furthermore, various other features of the invention appear from the attached description with reference to the drawings which illustrate non-limiting embodiments of a lighting device according to the invention.

• The figure 1 is a schematic perspective view partially exploded of a lighting device according to the invention.
• The figure 2 is a cross-section of the lighting device illustrated in figure 1 .

A lighting device according to the invention, designated as a whole by the reference 1 to the figure 1 can be described as a linear lighting device insofar as it has a linear light source E comprising one or more rows Rg of light-emitting diodes. A linear lighting device according to the invention generally has a length very much greater than the width of the lighting device without the invention excluding an embodiment of the lighting device in which it has a width very close to its width. length by the implementation of a sufficient amount of row of light emitting diodes. The linear qualifier is nonetheless relevant insofar as it relates to the alignment direction of the rows of light-emitting diodes.

The linear lighting device 1 comprises an elongate body 2 which extends along a longitudinal axis L. The elongated body 2 defines at least one receiving surface 3 of at least one substrate 4 carrying at least one row R of light-emitting diodes 5 according to the illustrated example, the elongate body 2 comprises a single receiving surface 3 which is substantially centered with respect to the elongate body 2 and on which is fitted a single substrate 4 carrying a single row R The substrate 4 may, for example, comprise a printed circuit board, in which the light-emitting diodes 5 are soldered. Of course, the substrate 4 may be made in any other suitable manner to ensure the mechanical strength of the light emitting diodes 5 and their power supply.

According to the illustrated example, each light-emitting diode 5 is associated, as is more particularly apparent from the figure 2 to a primary lens 6 which has a convex transmitting face 7, it being understood that the transmission face 7 could also to be flat. In addition, in this case each light emitting diode 5 is devoid of individual secondary lens.

According to the illustrated example, the elongated body 2 comprises two planar reflectors 10 located on either side of the receiving face 4. The two planar reflectors 10 extend parallel to the longitudinal axis L and form one with the other, an angle α between 100 ° and 170 °.

The elongate body 2 defines with the receiving surface 3 and the planar reflectors 10 a lighting chamber 11 in which the array of light-emitting diodes Rg, constituting the linear source E, is intended to be partially at least enclosed. According to the illustrated example, the elongate body 2 also comprises, opposite the lighting chamber 11 with respect to the reflectors 10, a chamber 12 capable of receiving a supply system for the light-emitting diodes 5. Of course, the implementation of such a chamber 12 is not necessary for producing the elongated body 2 of a linear lighting device according to the invention.

The lighting device according to the invention also comprises an elongated linear hood 20 which at least partly closes the lighting chamber 11. According to the invention, the hood 20 is also intended to let in or diffuse the light emitted by each linear source E. For this purpose, the cover 20 is made of an at least translucent and preferably transparent material such as for example a plastic material such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET) or polypropylene (PP) without this list being neither exhaustive nor exhaustive.

The cover 20 is also adapted to ensure a conditioning of the light emitted by each linear source E so as to direct and concentrate it in a preferred direction D, shifted to the right on the figure 2 . For this purpose, the cover 20 forms, in relation to each linear light source E, a linear lens 21 parallel to the longitudinal axis L of the body 2. According to the illustrated example Figures 1 and 2 , the cover 2 comprises a single linear lens 21.

According to the invention, each linear lens 21 comprises an outer emitting face 22 of the light which is symmetrical with respect to a sagittal plane S substantially parallel to the longitudinal axis L. When the cover 20 is fitted on the body 2, the sagittal plane S forms a plane of symmetry of the illumination chamber 11, the reflectors 10 then being the image of one another with respect to the sagittal plane S.

The linear lens 21 also has an inner face 23 for receiving the light of the light-emitting diodes 5 located opposite the external light-emitting face 22 of the light-emitting diodes 5. The linear lens 21 as a whole provides a transmission light emitted by said light-emitting diodes 5.

As is apparent from the figure 2 the outer face 22 has, in transverse cross-section, a preferably smooth convex shape with, preferably, a radius of curvature R greater than or equal to 8 mm and preferably between 13 mm and 30 mm. Preferably, the outer face 22 has the shape of a circular arc.

où R et le rayon de courbure de la face externe ou d'émission 22.The receiving face 23 is, for its part, shaped so that the lens 21 forms a kind of linear Fresnel lens. Thus, the receiving face 23 comprises, when viewed in cross section, a medial diopter 25 convex and on either side of the latter prisms parallel to the longitudinal axis L. The medial diopter 25 is offset relative to the sagittal plane S and defines a biconvex medial lens 26 whose optical axis 0, containing the center of curvature of the medial diopter 25, forms with the sagittal plane S an angle β between 10 ° and 45 ° in absolute value. The medial diopter 25 extends over an angular sector delimited by two planes P ₂₅ and P _'25 normal to the outer face 22 which form with each other an angle γ between 60 ° and 100 °. Moreover, the medial diopter 25 has a radius of curvature Rd which verifies the following relation: $$0.11R\le \mathrm{Rd}\le 0.20R$$

where R and the radius of curvature of the outer face or emission 22.

In addition, the medial lens has a thickness e, measured between two planes perpendicular to its optical axis and tangent, on the one hand, to the medial diopter 25 and, on the other hand, to the emission face 22 which preferably verifies but not necessarily the relation: $$0.15R\le \mathrm{e}\le 0.24R$$

The receiving face 23 also has on one side of the medial diopter 25, corresponding to the half-plane, delimited by the sagittal plane S, in which the major part of the medial lens 26 is located, a first lateral prism 31 which is adjacent to the medial diopter 25.

The receiving face 23 comprises on the other side of the medial diopter 25 and opposite the first prism 31, a series of prisms parallel to the first prism 31. This series of prisms comprises at least one second lateral prism 32 and a third Lateral prism 33. The second lateral prism 32 is then adjacent to the medial diopter 25 and the third prism 33. In this case the series of prisms also comprises a fourth lateral prism 34 located opposite the second lateral prism 32 with respect to the third lateral prism 33.

Each lateral prism comprises a medial face 40, partly at least flat, situated on the side of the sagittal plane S and a lateral face 41, partly at least flat, located opposite the sagittal plane S with respect to the medial face 40 The medial 40 and lateral 41 faces of each prism are substantially parallel to the longitudinal axis L. The medial 40 and lateral 41 faces of the same prism join to form the apex 42 of the corresponding prism. In addition, the medial and lateral faces 30 of two consecutive prisms meet to form a longitudinal groove 43 for separating the prisms. The depth of each longitudinal groove 33 is then measured between a plane tangent to the vertices 32 of the two prisms bordering the groove and a plane tangent to the bottom of the groove if the latter is curved or between a plane tangent to the vertices 32 of the two prisms bordering the throat and the bottom of the throat if this angular seen in cross section. In this case, the groove 43 separating the second lateral prism 32 from the third lateral prism 33 has a depth greater than the depth of the groove separating the third lateral prism 33 from the fourth lateral prism 34.

In a preferred manner, the plane portions of the lateral 41 and medial faces 40 of the same lateral prism form an angle of between 15 ° and 60 °. In addition, the flat portion of the medial face 40 of each prism forms with the sagittal plane S an angle of between 0 ° and 45 ° in absolute value. Similarly, the flat portion of the lateral face of each prism forms with the sagittal plane S an angle of between 5 ° and 80 ° in absolute value

According to the illustrated example, the flat portion of the lateral face 41 of the first prism 31 forms with the sagittal plane S an angle of between 45 and 80 degrees in absolute value. The flat portion of the lateral face 41 of the second prism 32 forms with the sagittal plane S an angle of between 5 ° and 40 ° in absolute value. The flat part of the lateral face 41 of the third prism 33 forms with the sagittal plane S an angle of between 30 ° and 60 ° in absolute value. Still according to the illustrated example, the flat portion of the lateral face 41 of the fourth prism 34 forms with the sagittal plane S an angle of between 10 ° and 45 ° in absolute value.

• la hauteur H₁ du premier prisme 31 vérifie 0,11 R ≤ H₁ ≤ 0,27 R,
• la hauteur H₂ du deuxième prisme 32 vérifie 0,15 R ≤ H₂ ≤ 0,24 R,
• la hauteur H₃ du troisième prisme 33 vérifie 0,11 R ≤ H₃ ≤ 0,20 R,
• la hauteur H₄ du quatrième prisme 34 vérifie 0,07 R ≤ H₄ ≤ 0,12 R.

où R correspond au rayon de courbure de la face externe 22.Moreover, according to the illustrated example and so that the linear lens 21 collects a maximum of the light emitted by the linear source E to focus it in the preferred direction D, the heights of the lateral prisms 31 to 34 verify the following relations:

• the height H ₁ of the first prism 31 satisfies 0.11 R ≤ H ₁ ≤ 0.27 R,
• the height H ₂ of the second prism 32 satisfies 0.15 R ≤ H ₂ ≤ 0.24 R,
• the height H ₃ of the third prism 33 satisfies 0.11 R ≤ H ₃ ≤ 0.20 R,
• the height H ₄ of the fourth prism 34 satisfies 0.07 R ≤ H ₄ ≤ 0.12 R.

where R corresponds to the radius of curvature of the outer face 22.

The height of each prism is then measured between the apex of the corresponding prism and the outer face 22, along a bisecting plane of the plane portions of the medial and lateral faces of said prism.

Furthermore, according to the illustrated example, the apex of the emission face 7 of each light emitting diode 5 is located at a distance d from the top of the outer face less than or equal to 0.74 R and, preferably, lower or equal to 0.31 R, where R is the radius of curvature of the outer face. This optimizes the luminous efficiency of the linear lighting device. In the context of the illustrated example, the top of the emission face 7 of the primary lens of each light emitting diode 5 is, moreover, situated between, on the one hand, a plane P42 passing through the points of the two extreme lateral prisms 31 and 34, the farthest 32 from the apex of the outer face 22 and, on the other hand, a plane tangent to the apex of the outer face 22.

In the present case, the apex of the emission face 7 of the primary lens of each light-emitting diode 5 is also situated between a plane P10 passing through the lateral edges of the reflectors 10 and a plane tangential to the apex of the outer face 22. It should be noted that here plans P42 and P10 are almost confused knowing that such a configuration is not imperative.

A linear lighting device, according to the invention and as thus produced, makes it possible to redirect at least 90% or even 95% of the light emitted by the diodes in the preferred direction D. Indeed, the linear biconvex medial lens 26 collimates the light from the diodes 5 in the preferred direction D along a narrow cone centered on its optical axis O while the linear prisms allow, after total internal reflection to the linear lens 21, to redirect the light in the preferred direction. In addition, the planar reflectors ensure a recycling of the light possibly reflected by the face 23 and the light from the light-emitting diodes 5 which would not have directly reached the reception face 23.

The lighting device described above in connection with the Figures 1 and 2 , comprises a linear light source E formed of a single row RG of light-emitting diodes R. However, according to the invention, the linear light source E could comprise several rows of LEDs juxtaposed Rg.

Of course, various other variants of the lighting device according to the invention can be envisaged within the scope of the appended claims.

Furthermore, it should be understood that several linear lighting devices according to the invention can be combined in various combinations to form a luminaire.

Claims (15)

1. A linear lighting device with light-emitting diodes comprising at least:

   - an elongated body (2) comprising at least one surface (3) for receiving at least one substrate (4) bearing a linear light source comprising at least one row (Rg) of light-emitting diodes (5) aligned along a longitudinal axis (L) of the body and delimiting, at least in part, at least one elongated linear lighting chamber (11) in which the diodes (5) are located,

   - an elongated linear lid (20) closing the fighting chamber (11), characterized in that the lid (20) forms, in relation with the linear source, a linear lens (21), at least translucent, of longitudinal axis parallel to the longitudinal axis (L) of the body (2), with an external light emitting face (22) and an inner light receiving face (23) for emitting and receiving the light of the diodes (5), the emitting face (22) having, in cross-section, a convex shape, and the receiving face (23) comprising, in cross-section :

   - an offset convex medial dioptre (25) that defines with the external face a biconvex medial lens (26) whose optical axis (O) is laterally offset with respect to a sagittal plane (S),

   - on one side of the medial dioptre (25), a first lateral prism (31) that is adjacent to the medial dioptre (25),

   - on the other side of the medial dioptre (25), a series of prisms parallel to the first prism (31) that comprises at least one second lateral prism (32) and one third lateral prism (33), the second lateral prism (32) being adjacent to the medial dioptre (25) and to the third lateral prism (33),

   each lateral prism having a medial face (40) and a lateral face (41) at least in part planar, connecting with each other at a corresponding apex of the prism, the lateral prisms each having a height, measured between the apex of the corresponding prism and the external face, the height (H₂) of the second lateral prism (32) being higher than or equal to the thickness (e) of the medial lens (26), measured between the apex of the medial dioptre (25) and the external face (22).
2. The linear lighting device according to the preceding claim, characterized in that the centre of curvature of the medial dioptre (25) is located on a plane (O) forming with the sagittal plane (S) an angle comprised between 10° and 45° in absolute value.
3. The linear lighting device according to one of the preceding claims, characterized in that the medial dioptre (25) extends over an angular sector delimited by two planes normal to the external face (22) that form, relative to each other, an angle comprised between 60° and 100°.
4. The linear lighting device according to one of the preceding claims, characterized in that the radius of curvature Rd of the medial dioptre (25) verifies 0.11 R ≤ Rd ≤ 0.20 R, where R is the radius of curvature of the emitting face.
5. The linear lighting device according to one of the preceding claims, characterized in that the planar parts of the lateral and medial faces of a same lateral prism form an angle comprised between 15° and 60°.
6. The linear lighting device according to one of the preceding claims, characterized in that:

   - the radius of curvature R of the external face (22) is comprised between 13 mm and 30 mm,

   - the thickness e of the medial lens verifies 0.15 R ≤ e ≤ 0.24 R,

   - the height H₁ of the first prism (31) verifies 0.11 R ≤ H₁ ≤ 0.27 R,

   - the height H₂ of the second prism (32) verifies 0.15 R ≤ H₂ ≤ 0.24 R,

   - the height H₃ of the third prism (33) verifies 0.11 R ≤ H₃ ≤ 0.20 R.
7. The linear lighting device according to one of the preceding claims, characterized in that the series of prisms comprises a fourth lateral prism (34) parallel to the other lateral prisms and adjacent to the third lateral prism (33) by being located on the opposite side from the second lateral prism (32) with respect to the third lateral prism (33), the fourth lateral prism (34) having a medial face (40) (30) and a lateral face (41) (31) at least in part planar, connecting with each other at an apex of the fourth lateral prism (34).
8. The linear lighting device according to the preceding claim, characterized in that the height (h) of the fourth prism (34), measured between the apex of the fourth prism (34) and the external face (22), verifies the following relation : 0.07 R ≤ H₄ ≤ 0.12 R, where R is the radius of curvature of the external face (22).
9. The linear lighting device according to claim 7 or 8, characterized in that the planar part of the lateral face (41) of the fourth prism (34) forms with the sagittal plan an angle comprised between 10° and 45° in absolute value.
10. The linear lighting device according to one of the preceding claims, characterized in that:

    - the planar part of the medial face (40) (30) of each prism forms with the sagittal plane (S) an angle comprised between 0° and 45° in absolute value,

    - the planar part of the lateral face (41) (31) of each prism forming with the sagittal plane (S) an angle comprised between 5° and 80° in absolute value.
11. The linear lighting device according to one of the preceding claims, characterized in that:

    - the planar part of the lateral face (41) (31) of the first prism (31) forms with the sagittal plane (S) an angle comprised between 45° and 80° in absolute value,

    - the planar part of the lateral face (41) (31) of the second prism (32) forms with the sagittal plane (S) an angle comprised between 5° and 40° in absolute value,

    - the planar part of the lateral face (41) (31) of the third prism (33) forms with the sagittal plane (S) an angle comprised between 30° and 60° in absolute value.
12. The linear lighting device according to one of the preceding claims, characterized in that each diode (5) comprises a primary lens (6) associated with a convex or planar emitting face (7) and in that the apex of each emitting face (7) of each diode is located at a distance (d) from the apex of the external face (22) (26) lower than or equal to 0.74 R and preferably lower than or equal to 0.31 R, where R is the radius of curvature of the external face (22).
13. The linear lighting device according to the preceding claim, characterized in that the apex of the primary lens (6) of each diode (5) is located between a plane (P42) passing through the points of the prisms that are the farthest from the apex of the external face (22) and a plane tangent to the apex of the external face (22).
14. The linear lighting device according to one of the preceding claims, characterized in that the body (2) comprises, in the lighting chamber (11), two planar reflectors (10) extending parallel to the longitudinal axis (L) of the body (2) by being located on either side of the receiving surface (3) and forming, relative to each other, an angle comprised between 100° and 170°.
15. The linear lighting device according to one of the preceding claims, characterized in that the body (2) is made of metal.

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