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EP-4736579-A1 - MULTILAYER POLYCHROMATIC LIGHT MODULE WITH A STACK OF MULTIPLE ELECTROLUMINESCENT FILMS

EP4736579A1EP 4736579 A1EP4736579 A1EP 4736579A1EP-4736579-A1

Abstract

The invention relates to a light module (1) comprising: a stack of n flexible superimposed electroluminescent films (2 A , 2 B ,... 2 n ), where n ≥ 2, and wherein the last electroluminescent film (2 n ) is located above the first (2 A ), and each comprising: • a flexible support layer (5); and • an intermediate layer (6) located on the support layer (5) comprising multiple electroluminescent elements (7); - a transparent protective layer (3) located on the intermediate layer (6) of the last electroluminescent film; - a pair of electrical connection elements (4a, 4b) connected to each electroluminescent element (7) and connected to a power supply (15); wherein - each electroluminescent film after the first comprises at least one transparent exposure portion (T) without any electroluminescent elements that is positioned and dimensioned such that electroluminescent elements of an electroluminescent film are not masked by an electroluminescent element belonging to an electroluminescent film located above.

Inventors

  • ALVEAR, Eduardo
  • SIDAHMED, Beddar

Assignees

  • Valeo Vision

Dates

Publication Date
20260506
Application Date
20240620

Claims (19)

  1. [Claim 1] Light module (1) characterized in that it comprises: - a stack of n flexible electroluminescent films (2A, 2B, ... 2n) superimposed on each other, such that n > 2, such that the set of n electroluminescent films (2A, 2B, ... 2n) comprises a first and a last electroluminescent film (2A, 2n), with the last electroluminescent film (2n) being located above the first electroluminescent film (2A); each electroluminescent film (2A, 2B, ... 2n) comprising: o a flexible support layer (5), and o a flexible intermediate layer (6) located on the support layer (5) and comprising several distinct electroluminescent elements (7), spaced longitudinally and laterally in a plane of the electroluminescent film (2A, 2B, ... 2n) and electrically insulated from each other; - a flexible and transparent protective layer (3) located on the intermediate layer (6) of the last electroluminescent film (2n); - a pair of electrical connection elements (4a, 4b) per electroluminescent element (7), comprising a first and a second electrical connection element (4a, 4b) each electrically connected to the electroluminescent element (7) and each adapted to be connected to an alternating current power supply (15); where - each electroluminescent film (2B, ... 2n) at least after the first (2A) comprises at least one transparent exposure part (T) devoid of electroluminescent element (7), positioned longitudinally and laterally contiguous in the plane of the electroluminescent film (2B, ... 2n) to at least two electroluminescent elements (7), and dimensioned such that electroluminescent elements (7) of an electroluminescent film (2A, 2B ... 2n-i) are not masked by an electroluminescent element (7) belonging to an electroluminescent film (2B ...
  2. 2 n ) located above. [Claim 2] Light module (1) according to claim 1, characterized in that, for at least one electroluminescent film (2A, 2B, ... 2n), an electroluminescent element (7) successively comprises: a first flexible electrode layer (8) made of conductive material, located on the flexible support layer (5) of said electroluminescent film (2A, 2B, ... 2n); a flexible electrically insulating layer (9) made of dielectric material, located on the first electrode layer (8); a flexible electroluminescent layer (10) located on the electrically insulating layer (9) and comprising a phosphor layer (12) having a refractive index rn U m ; and a second flexible and transparent electrode layer (11) made of conductive material having a refractive index neiec and located on the electroluminescent layer (10).
  3. [Claim 3] Light module (1) according to claim 2, characterized in that at least one electroluminescent layer (10) also comprises at least one refractive index matching element (13) having a refractive index Hng such that nium > Hng > Helect-
  4. [Claim 4] Light module (1) according to any one of claims 2 to 3, characterized in that at least one layer of luminophore (12) comprises zinc sulfide doped with at least one metal including copper.
  5. [Claim 5] Light module (1) according to any one of claims 2 to 4, characterized in that, within the same electroluminescent film (2A, 2B, ... 2n), the phosphor layers emit a color different from those of the other electroluminescent film(s) (2A, 2B, ... 2n ).
  6. [Claim 6] Light module (1) according to any one of claims 2 to 5, characterized in that each support layer (5), each first electrode layer (8), each electrically insulating layer (9) and each phosphor layer (12) are transparent.
  7. [Claim 7] Light module (1) according to any one of the preceding claims, characterized in that, for electroluminescent elements (7), the pair of electrical connection elements (4a, 4b) associated with a light-emitting element (7) is supplied with electricity independently of the other light-emitting elements (7).
  8. [Claim 8] Light module (1) according to any one of the preceding claims, characterized in that, for electroluminescent elements (7), the pair of electrical connection elements (4a, 4b) associated with an electroluminescent element (7) is supplied with electricity via a control unit (16) connected to the power supply (15).
  9. [Claim 9] Light module (1) according to any one of the preceding claims, characterized in that, within at least one electroluminescent film (2A, 2B, ... 2n), the space (E) located between neighboring electroluminescent elements (7) is occupied by a flexible insulating material made of dielectric material (17).
  10. [Claim 10] Light module (1) according to any one of the preceding claims, characterized in that, within at least one electroluminescent film (2A, 2B, ... 2n), characterized in that the space (E) located between neighboring electroluminescent elements (7) is occupied by polyethylene terephthalate, siloxane based on polymerized silicon monoxide, polymethyl methacrylate, polycaprolactone, polycarbonate, cycloolefin polymer or by a mixture of at least two of these products.
  11. [Claim 1 1 ] Light module (1 ) according to any one of the preceding claims, characterized in that, within at least one electroluminescent film (2A, 2B, ... 2n), the space (E) located between neighboring electroluminescent elements (7) is occupied by the same material as that forming the protective layer (3).
  12. [Claim 12] Light module (1) according to any one of the preceding claims, characterized in that electroluminescent elements (7) have an upper face in the form of a point, a circle, an oval, a chevron, an oblong, a square, a rectangle, a triangle, a star, a cross, a diamond, a polygon, a honeycomb, an alphanumeric character, or in the form of a combination of at least two of these patterns.
  13. [Claim 13] Light module (1) according to any one of the preceding claims, characterized in that electroluminescent elements (7) are arranged in a matrix of pixels.
  14. [Claim 14] Light module (1) according to any one of the preceding claims, characterized in that electroluminescent elements (7) each have an upper face whose surface area is between 5 mm 2 and 1 cm 2 .
  15. [Claim 15] Light module (1) according to any one of the preceding claims, characterized in that electroluminescent elements (7) each have an upper face whose surface area is between 100 pm 2 and 10000 pm 2 .
  16. [Claim 16] Light module (1) according to any one of the preceding claims, characterized in that at least one protective layer (3) comprises a transparent anti-UV material, an anti-UV additive or a transparent anti-UV coating.
  17. [Claim 17] Light module (1) according to any one of the preceding claims, characterized in that at least one protective layer (3) comprises a layer of transparent anti-UV material chosen from an acrylic resin, a mixture of high density polyethylene and zinc oxide, polycarbonate, polyamide-imide and poly(vinylidene fluoride).
  18. [Claim 18] Element for a vehicle, characterized in that it is at least partially covered by a light module (1) according to any one of the preceding claims.
  19. [Claim 19] Vehicle element according to the preceding claim, characterized in that said element is a bodywork part, a dashboard, a decorative part, a grille, a logo or an optical element.

Description

DESCRIPTION TITLE: Multilayer and polychrome light module, with superposition of several electroluminescent films TECHNICAL FIELD OF THE INVENTION [0001] The technical field of the invention is that of polychrome light modules. [0002] The present invention applies in particular, but not exclusively, to the display of static, dynamic information or animations from polychrome light patterns generated by electroluminescent films. TECHNOLOGICAL BACKGROUND OF THE INVENTION [0003] Nowadays, it is known to use screens, such as LCD screens, to produce such displays in many devices, for signaling, information, aesthetic purposes of personalization or creation of ambiance. [0004] However, such technology is not only expensive, but also sensitive to environmental conditions such as temperature, humidity or UV radiation. [0005] Furthermore, these screens are not very flexible and therefore cannot be integrated into any type of equipment. [0006] There is therefore a need for a flexible light module capable of producing a polychrome display or animation, and being robust, inexpensive and easy to integrate into any type of equipment. [0007] Advantageously, such a flexible and polychrome light module can also be transparent. [0008] Advantageously, such a flexible and polychrome luminous film is also transparent. SUMMARY OF THE INVENTION [0009] The invention offers a solution to the problems mentioned above, by providing a light module, preferably transparent, comprising several electroluminescent films each comprising at least one layer of electroluminescent elements capable of each emitting a color different from those of the i electroluminescent films, the light module being both thin, flexible and very bright when supplied with alternating electric current. [0010] One aspect of the invention relates to a light module comprising: a stack of n flexible electroluminescent films superimposed on each other, such that n > 2, such that the set of n electroluminescent films comprises a first and a last electroluminescent film, with the last electroluminescent film being located above the first electroluminescent film; each electroluminescent film comprising: a flexible support layer, and a flexible intermediate layer located on the support layer and comprising several distinct electroluminescent elements, spaced longitudinally and laterally in a plane of the electroluminescent film and electrically insulated from each other; a flexible and transparent protective layer located on the intermediate layer of the last electroluminescent film; a pair of electrical connection elements per electroluminescent element, comprising a first and a second electrical connection element each electrically connected to the electroluminescent element and each adapted to be connected to an alternating current power supply; wherein each electroluminescent film at least after the first comprises at least one transparent exposure portion devoid of electroluminescent element, positioned longitudinally and laterally contiguous in the plane of the electroluminescent film to at least two electroluminescent elements, and dimensioned such that electroluminescent elements of an electroluminescent film are not masked by an electroluminescent element belonging to an electroluminescent film located above. [0011] The use of superimposed electroluminescent films having transparent exposure portions revealing the electroluminescent elements of the lower films advantageously allows a polychrome display or animation to be produced, particularly in the case where each film is designed to emit a different colour. The use of flexible electroluminescent films also allows a flexible light module to be obtained, therefore adaptable to many functionalities, to be applied to complex concave and/or convex surfaces, its integration into any type of equipment being facilitated. In addition, the electrical consumption of electroluminescent films is more than three times lower than that of LEDs. [0012] According to one aspect of the invention, for at least one electroluminescent film, an electroluminescent element successively comprises: a first flexible electrode layer made of conductive material, located on the flexible support layer of said electroluminescent film; a flexible electrically insulating layer made of dielectric material, located on the first electrode layer; a flexible electroluminescent layer located on the electrically insulating layer and comprising a phosphor layer having a refractive index rn U m ; and a second flexible and transparent electrode layer made of conductive material having a refractive index neiec and located on the electroluminescent layer. [0013] This type of electroluminescent element advantageously has a very high luminosity, allowing in particular to contrast with ambient light. In addition, it is advantageously robust, inexpensive and easy to implement. Finally, the nature and the low thickness of each of the electroluminescent elements