Light management system and sound manufacturing process

Abstract

The present invention relates to a Light Management System (LMS) and its manufacturing method, said system (LMS) comprising illumination achieved using uncollimated light directed towards a flexible Light Guide Plate (LGP) comprising a core (1) in the form of a light-transmitting sheet, characterized in that it comprises: - A first film (10) adjacent to a first face of the core (1) and comprising at least one collimation structure (2) using a design of free-form micro-optical elements (FF-MOEs); - At least one coupling structure (3) using a prism design, preferably an air prism, on a second face of the core (1), opposite said first face; - Said collimation structure on the first film (10) directing the light towards said coupling structure (3) on the second face to optimize the efficiency of the light coupling in the LGP.Figure for the abbreviation: Figure 2.

Description

Title of the invention: Light management system and sound manufacturing process

[0001] The present invention relates to the field of lighting devices and light in general, and in particular to light guides in the form of plates, or even more precisely, sheets or films. Indeed, a recurring problem in this field concerns obtaining light-diffusing devices that can be exposed to a light source and transmit light optimally, while also being thin (for example, on the order of a few tens of microns) and ideally flexible, so as to be easily installed on various types of light sources and on various substrates, including non-planar substrates. In fact, a light guide generally relies on specific shapes at the interface between the inside of the light guide and the surrounding environment. This problem is all the more difficult to overcome as there is a growing desire for light guide plates that are thin enough to be flexible.

[0002] One object of the present invention is to overcome at least some of the drawbacks of the prior art by proposing a light management system using a flexible support that provides satisfactory light guidance despite the thinness of the system.

[0003] This goal is achieved by a Light Management System comprising illumination achieved using non-collimated light directed towards a flexible Light Guide Plate (LGP) comprising a core in the form of a light-transmitting sheet; Characterized by what it includes - A first film adjacent to a first face of the core and comprising at least one collimation structure using a design of free-form micro-optical elements (FF-MOEs, for the English Free-Form Micro Optical Elements); - A coupling structure using a prism design, preferably an air prism, on a second face of the core, opposite said first face; - Said collimation structure on the first film directing light towards said coupling structure on the second side to optimize the efficiency of light coupling in the LGP.

[0004] According to another feature, said coupling structure is formed on a second film adjacent to said second face of the core.

[0005] According to another feature, said coupling structure is arranged so as to direct the coupled light out of an area including said collimation structures.

[0006] According to another feature, said illumination with non-collimated light is a white light illumination.

[0007] According to another feature, the system further comprises a decoupling of said light injected into said LGP using the same air prism structure to efficiently decouple said light.

[0008] According to another feature, said first and the core form a transparent flexible film, optionally with said second film, the transmission of light to said opposite face of the transparent flexible film being prevented by said coupling structure.

[0009] According to another feature, said transparent flexible film has variable dimensions and in particular an evolving height ranging from a few tens of micrometers while exhibiting optical characteristics comparable to those of conventional freeform optics which are bulky.

[0010] According to another feature, at least the collimation structures are formed by said first film which is laminated onto said core or fixed onto it by an adhesive substance whose refractive index is equal to or close to that of said core.

[0011] According to another feature, the coupling and / or decoupling structures are laminated onto said core.

[0012] According to another feature, air prism structures are arranged directly on the core material instead of laminated films, to improve manufacturing efficiency and reduce material consumption.

[0013] Another objective is to propose a manufacturing process for an efficient Light Management System as proposed in this application, limiting manufacturing costs and optimizing manufacturing speed.

[0014] This goal is achieved by a method for manufacturing a Light Management System comprising the following steps: - Creation of an impression master using greyscale lithography to produce optical patterns on a surface; - Printing optical patterns onto a first film using direct UV printing based on the impression master, to obtain at least a collimation structure; - Printing optical patterns on a first film using direct UV printing based on the imprint master or the arrangement of air prism structures directly on a core of a flexible light guide plate, to obtain at least one coupling structure; - Assembly of films and core to form a flexible LGP including optical patterns and / or air prism structures.

[0015] According to another feature, the process further includes laser writing processes for originating and replicating optical structures to ensure precise and personalized patterns.

[0016] According to another feature, the process further includes a roll-to-roll replication process for optical printing.

[0017] According to another feature, the process further comprises the manufacture of a batch of films printed with the designed structure and origin by a UV printing replication process.

[0018] According to another feature, the impression master is designed to produce optical patterns on the film sheets in order to improve the efficiency of light coupling and decoupling in the flexible light guide plate.

[0019] According to another feature, the greyscale lithography is carried out using a specialized lithography mask to create subtle variations of greyscale on the impression master.

[0020] According to another feature, direct UV printing is carried out by selectively exposing the photosensitive material on the film sheet to a UV light source through the impression master.

[0021] Such methods (or processes) optimize the manufacturing process for scalability and cost-effectiveness by using roll-to-roll replication for optical printing, significantly reducing material consumption and enabling cost-effective manufacturing methods. Furthermore, integrating at least one collimation structure with air prism designs on the films (and / or the core) allows for synergistic effects between coupling and light extraction within the LGP.

[0022] Other features and advantages of the present invention will become clearer upon reading the description of various embodiments below, made with reference to the accompanying drawings, in which:

[0023] [Fig-1] [Fig.1] represents a schematic view, in cross-section transverse to the plane of the LGP, of a collimation structure of a Light Management System (LMS) according to various embodiments;

[0024] [Fig.2] [Fig.2] represents a schematic view of the management system (MS) of light according to various embodiments;

[0025] [Fig.3] [Fig.3] represents a schematic view of the management system (MS) of light according to various embodiments;

[0026] [Fig.4a] [Fig.4a] represents a schematic cross-sectional view of part of a coupling structure showing its periodicity;

[0027] [Fig.4b] [Fig.4b] represents a schematic view of the path of light and the angles followed by light in a part of a coupling structure;

[0028] [Fig.5] [Fig.5] represents a schematic view of management systems (MS) provided on an LGP light guide plate according to various embodiments.

[0029] The present invention relates to an innovative light management system specifically designed to improve the efficiency of light coupling in the context of a flexible light guiding plate (LGP). LGPs are commonly used in various applications such as automotive signage and image projection, where static or animated light patterns are required.

[0030] In particular, the present invention is especially suited to mobile lighting devices, for example in the automotive field and for signaling, but also for lighting in general. The invention is particularly suited to thin lighting devices that are flexible and can be mounted on various supports, including transparent supports, thanks to the LGP, which is also transparent.

[0031] The main technical problem addressed by the invention is the low efficiency of the coupling of incoming and outgoing light obtained by traditional LGPs. This inefficiency limits the brightness and sharpness of the light patterns produced, which is unacceptable for many applications, particularly in the automotive field.

[0032] The technical solution proposed by the invention involves the use of optical structures of varying dimensions, ranging from a few tens of micrometers, exhibiting optical characteristics comparable to those of large freeform optics. This light management system (SM) solution is based on the use of a film or sheet comprising a core (1) and at least one collimation sheet (10) or foil (2), as well as a structure (generally prismatic) for coupling (3) the light, either made in the core (1), for example by embossing or engraving, or juxtaposed to the core (1) in the form of a sheet (11) or foil comprising a prism, preferably an air prism.

[0033] The first leaf (10) acts as a collimator on a first face of the core (1) facing the light-emitting device, such as an LED (Light Emitting Diode), using a Freeform Micro-Optical Element (FF-MOE) design, to direct the light rays in the preferred direction, while the second face of the core (1) (equipped with a second leaf or with carvings in the material of the core (1)) serves for coupling (3) via a prism design, preferably an air prism (taking advantage of the refractive index of air for transmission parallel to the plane of the leaves and the core (1) (although other materials are conceivable)). Such a prism prevents the transmission of light towards the opposite side of the transparent film (or core) and allows the light to be directed into the desired area, for example outside the collimation area of ​​the first sheet (10). The coupled light is then guided into the core of the film (or core).

[0034] Illumination is preferably achieved using non-collimated white light, offering increased flexibility and versatility for various applications, for example, by a source such as an LED (light-emitting diode). Furthermore, some embodiments of the invention provide a solution for decoupling the light injected into the film, using the same prism structure (preferably an air prism) to effectively decouple the light from the film.

[0035] Compared to the nearest prior art, the invention offers several significant advantages, including a roll-to-roll replication process for optical printing, which considerably reduces material consumption and enables cost-effective manufacturing methods. Furthermore, manufacturing processes such as grayscale lithography and direct UV printing lithography are used to fabricate the optical structures, contributing to efficient and economical manufacturing.

[0036] The light management system (SM) described in this application represents a significant advance in the field of flexible optics, offering improved performance, cost-effective manufacturing and increased versatility for a variety of applications, particularly in the automotive field.

[0037] The term "light coupling" in this application refers to the process by which light from an external source is introduced or "coupled" into a specific optical material or device. In the context of the invention, light coupling occurs when uncollimated white light is directed to the flexible light guide plate (LGP) through the first sheet of the film, where it is then guided into the film core for optimal distribution.

[0038] The term "uncoupled light" can be considered an improper or ambiguous expression. It seems to refer to light that is not fully collimated or precisely directed. In the context of the invention, uncollimated white light refers to light that has not been focused or directed consistently, but rather emitted in various directions or angles. This uncollimated light is used as the illumination source in the proposed light management system (LMS).

[0039] The terms “Core” or “core” are used interchangeably in this application to refer to the light guide plate (in its thin thickness which nevertheless guides light) and / or its light-guiding material. Indeed, these terms, in the context of flexible light guide plates (LGPs), The core of the LGP refers to the central part of the device where light is guided and propagated. The core of the LGP is the central part or main layer of the device responsible for guiding light through the plate. It is typically made of a transparent material with specific optical properties, such as low light attenuation and high internal reflectance. This core layer (1) acts as a waveguide for the incident light, guiding it through the plate with minimal loss of light intensity. In the context of this application, the LGP core is where uncoupled light is directed after being coupled through the optical structures on the film sheets. Once in the core, the light is guided and propagated along the plate, enabling the desired light patterns or visual effects, such as those used in automotive signage or image projection.It should be noted that the invention is preferably applicable to direct-lit lighting rather than edge-lit lighting, but is not limited in this respect. The core can be made from various materials, such as polymethyl methacrylate (PMMA), polycarbonate, or other suitable transparent materials, depending on the specific requirements of the application and the desired optical performance.

[0040] The term "collimation" in this application refers to the process of making light parallel or directing light precisely. This generally involves the use of optical devices such as lenses to make light rays parallel. Collimation is important for achieving a uniform distribution of light and minimizing the divergence of light beams.

[0041] The term "light coupling" refers to the process of transferring light from an external source to a specific optical material or device. This may involve the implementation of optical structures to efficiently direct the light to the target device.

[0042] In the context of the invention, the first sheet of the film acts as a collimator, meaning that it is responsible for making the incoming light as parallel as possible for optimal distribution across the flexible light guide plate (LGP). The main objective of this step is to optimize the efficiency of light coupling in the LGP.

[0043] The terms "Prism" or "Air Prism" (used interchangeably, although "air" is preferred) refer to optical structures that utilize the differences in refractive index between air and a transparent material to manipulate light. These structures generally consist of inclined surfaces that reflect, refract, or deflect light in a controlled manner. The use of air prisms makes it possible to efficiently guide light through a transparent material while avoiding the light transmission to unwanted areas. In the context of the invention, the "AirPrism" design is used for the efficient coupling and decoupling of light in the flexible light guide plate, thus contributing to improving the overall efficiency of the light management system (SM).

[0044] The term Free-form micro-optics elements (FF-MOEs) refers to optical structures designed with a high degree of freedom in shape and distribution. Unlike traditional optical elements, which are often constrained by regular geometric shapes such as spherical or cylindrical lenses, FF-MOEs can have more complex and irregular shapes. This design freedom allows for the optimization of optical performance for specific applications by precisely manipulating the path of light. In the context of the invention, the FF-MOE design is used for the first sheet of the film, acting as a collimator to make the incoming light as parallel as possible before guiding it into the core of the flexible light-guiding plate.By combining these two optical designs in the proposed light management system (SG), it is possible to optimize the efficiency of light coupling, guiding, and decoupling, thus offering improved performance for a variety of applications.

[0045] The present application relates in particular to a light management system (SM) comprising illumination achieved using non-collimated light directed towards a flexible light guide plate (LGP) comprising a core (1) in the form of a light-transmitting sheet; Characterized by what it includes - A first film (10) adjacent to a first face of the core (1) and comprising at least one collimation structure using a design of free-form micro-optical elements (FF-MOEs, for the English Free-Form Micro Optical Elements); - at least one coupling structure (3) using a prism design, preferably an air prism, on a second face of the core (1), opposite said first face; - Said collimation structure on the first film (10) directing the light towards said coupling structure (3) on the second face to optimize the efficiency of light coupling in the LGP.

[0046] Collimation structures, generally similar to a blazed grating in preferred embodiments, ensure efficient light propagation within the core (1) LGP, reducing light loss by diffraction or divergence.

[0047] In certain embodiments, said coupling structure (3) is formed on a second film adjacent to said second face of the core (1).

[0048] In certain embodiments, said coupling structure (3) is arranged so as to direct the coupled light out of an area including said collimation structures.

[0049] Generally speaking, preferably this second film (11) or foil (as well as, preferably, the first film (10) or foil) is fixed to the core (1) by an adhesive having a refractive index similar or identical to that of the core (1). However, for the coupling structure (3) based simply on the presence of prisms, it is possible to dispense with the second film by directly forming these prismatic shapes in the second surface of the core (1), for example by embossing or engraving.

[0050] In some embodiments, said illumination with non-collimated light is white light illumination.

[0051] In certain embodiments, the management system (MS) further comprises decoupling said light injected into said LGP using the same air prism structure to efficiently decouple said light. No details are necessary regarding the decoupling structures, which are known to those skilled in the art and include, in particular, prismatic structures, such as air prisms similar to those used for coupling.

[0052] In certain embodiments, said first sheet and the core (1) form a transparent flexible film, optionally with said optional second film (11), the transmission of light to said opposite face of the transparent flexible film being prevented by said coupling structure (3).

[0053] In certain embodiments, said transparent flexible film has variable dimensions and in particular an evolving height ranging from a few tens of micrometers while exhibiting optical characteristics comparable to those of conventional freeform optics which are bulky.

[0054] In certain embodiments, at least the collimation structures are formed by said first film (10) which is laminated onto said core (1) or fixed to it by an adhesive substance having a refractive index equal to or close to that of said core (1). Important parameters include the size (s) of the LED, its distance (d) from the control system (SG), the size (a) of the control system (SG), the thickness (t) of the guide plate and the divergence of the collimated light, for example as shown in [Fig. 1].

[0055] In some embodiments, the coupling and / or decoupling structures are laminated onto said core (1).

[0056] In some embodiments, air prism structures are arranged directly on the core material (1) instead of laminated films, to improve manufacturing efficiency and reduce material consumption.

[0057] The present application also relates in particular to a method for manufacturing a light management system (SM) comprising the following steps: - Creation of a master impression using greyscale lithography to produce optical patterns on a surface; - Printing optical patterns on a first film (10) using direct UV printing based on the impression master, to obtain at least one collimation structure (2); - Printing optical patterns on a second film (11) using direct UV printing based on the imprint master or the arrangement of air prism structures directly on a core (1) of a flexible light guide plate (LGP), to obtain at least one coupling structure (3); - Assembly of films and core (1) to form a flexible LGP comprising optical patterns and / or air prism structures.

[0058] In some embodiments, the method further includes laser writing processes for originating and replicating optical structures to ensure precise and personalized patterns.

[0059] In some embodiments, the process further includes a roll-to-roll replication process for optical printing.

[0060] In some embodiments, the process further includes manufacturing a batch of films printed with the designed structure and origin by a UV printing replication process.

[0061] In some embodiments, the impression master is designed to produce optical patterns on the film sheets in order to improve the efficiency of light coupling and decoupling in the flexible light guide plate.

[0062] In some embodiments, greyscale lithography is performed using a specialized lithography mask to create subtle greyscale variations on the impression master.

[0063] In some embodiments, direct UV printing is carried out by selectively exposing the photosensitive material on the film sheet to a UV light source through the impression master.

[0064] In certain embodiments, said method comprises said assembly which is carried out by optical bonding using adhesive materials having a refractive index corresponding to that of the collimator film and / or the core film and / or the air prism film. Preferably, a thermosetting material such as UV resin is chosen.

[0065] Such methods or processes make it possible to optimize the manufacturing process for scalability and profitability by using roll-to-roll replication for optical printing, significantly reducing consumption of materials and enabling cost-effective manufacturing methods. Furthermore, the integration of collimation structures with air prism designs on the films (and / or the core (1)) allows for synergistic effects between coupling and light extraction within the LGP.

[0066] Various embodiments relate to a method for manufacturing a light management system (LMS). In particular, this method uses Grayscale Lithography for Direct UV Lithography ('creation of masters by grayscale lithography used for direct UV lithography'). Grayscale lithography is a manufacturing technique that allows the creation of complex and precise patterns on a surface using subtle variations in grayscale levels. Unlike traditional lithography where patterns are binary (black or white), grayscale lithography allows the creation of shades of gray corresponding to variations in height or thickness on the surface (but also dimensions in general, and not just height or thickness).This offers greater design freedom and allows for the production of patterns with softer contours and smoother transitions between regions.

[0067] Some embodiments utilize Direct UV Printing, which is a manufacturing method that uses ultraviolet (UV) light to polymerize a photosensitive material and create patterns on a surface. In the Direct UV Printing process, a polymerizable material is applied to a substrate and then exposed to a UV light source through a mask to selectively polymerize the material and form the desired patterns.

[0068] In the context of the invention, the printing process involves creating printing masters using grayscale lithography. These printing masters have complex and precise patterns that are used to create optical structures on the film sheets. Once the printing masters are created, they are used in the direct UV printing process to produce the film sheets with the desired optical patterns. This approach makes it possible to produce highly customized and precise optical structures, contributing to the overall efficiency of the proposed light management system (LMS).

[0069] The use of FF-MOEs for collimation, combined with AirPrisms for light coupling and decoupling, improves the efficiency and performance of light management systems. Similarly, the manufacturing process involving grayscale lithography and direct UV printing lithography offers advantages such as precise control of optical structures and cost-effective manufacturing.

[0070] The integration of collimation with air prism structures, achieved through films, offers a unique approach to light management to improve the coupling and distribution of light in flexible light guide plates.

[0071] The advantages of the present invention therefore include (by way of example and not exclusively) the following synergistic effects:

[0072] A first effect relates to improved light coupling efficiency: By integrating collimation structures with air prisms on the same film, the management system (MS) achieves more efficient light coupling in the flexible light guide plate (LGP). The collimation structures can ensure that incoming light is directed towards the coupling structures such as the air prisms, optimizing the coupling process. An example of the use of this first effect concerns automotive signaling applications, where high-brightness light patterns are crucial for visibility. This improved coupling efficiency leads to brighter and sharper light projection patterns (including those of turn signals or brake lights, in addition to other lighting devices).

[0073] A second effect relates to improved light extraction: The combination of collimation and air prisms also improves the light extraction from the LGP, ensuring that a greater proportion of light is directed towards the desired output direction. An example of the use of this second effect concerns projection systems for displaying images, such as head-up displays (HUDs) in vehicles. This improved light extraction results in clearer and more vivid projected images, improving visibility for the driver and enabling the projection of patterns used in field-of-view (FoV) analysis.

[0074] A third effect relates to the reduction of light loss: By collimating and efficiently guiding light through the LGP using air prisms, the management system (GS) experiences less loss due to dispersion or divergence, resulting in a more uniform and directed light output. An example of the use of this third effect concerns signage applications where uniform illumination is essential for legibility; this reduction in light loss leads to displays with consistent brightness and reduced hot spots.

[0075] A fourth effect relates to an optimized manufacturing process: The use of films with integrated collimation structures and air prisms simplifies the manufacturing process of LGPs, thereby reducing production costs and enabling scalable manufacturing methods. An example of the application of this third effect concerns mass-produced consumer electronics such as smartphones or tablets, where thin and lightweight displays are desirable; this optimized manufacturing process could lead to more affordable and energy-efficient devices with improved display performance.

[0076] Overall, the synergistic effects of combining collimation with air prism structures in films lead to advances in various applications requiring efficient light management, ranging from automotive lighting systems to display technologies and beyond.

[0077] In a specific, concrete, and simplified example (non-limiting, and even unpreferred), angle alpha1 (al) can be fixed at 40° and angle alpha2 (a2) at 90°. The periodicity must be calculated knowing the height of the prisms, in particular knowing, for example, that aerial prism structures have a fixed height of 30 pm. Thus, the periodicity (the space between successive repetitions of the prismatic structures) can be defined as follows: Periodicity = (sin(90-al) / sin(al)+sin(90-a2) / sin(a2))*30 pm. In such an example, the periodicity is therefore 35.75 pm, as illustrated for example in [Fig.4a].

[0078] Furthermore, the arrangement of the coupling structure (3) can also be defined in more detail, particularly with reference to [Fig. 4b], which is also not limiting. If we set e = sin 1(n.sin(jr-2.a2-ai)), where n is the refractive index of the material, let j = sin1(sin(jr-a2-ai-e) / n). Then k = ir / 2-a2-j The management system (MS) is then well-sized if tan(k) < t / a (neglecting the depth of the prisms compared to t). Note that: a2min = sin '(1 / n) Thus, for examples of angles (different from those shown in [Fig. 4b]) such as: a2 = 45°, ai = 90°, n = 1.5 e = O,j = 28.13°, k = 18.87°, t / a >0.303

[0079] Figure 5 schematically represents a light guide plate (LGP) equipped with a plurality of control systems (SG) on one of its surfaces. It can be seen that it is possible to provide a plurality of control systems (SG) on the same plate (LGP), which can also be easily cut into several plates, depending on the requirements, which offers a clear advantage in terms of the manufacturing process.

[0080] This application describes various technical features and advantages with reference to the figures and / or various embodiments. Those skilled in the art will understand that the technical features of a given embodiment can in fact be combined with features of another embodiment unless the contrary is explicitly stated, or it is obvious that such features are incompatible, or that the combination does not provide a solution to at least one of the technical problems mentioned in this application. Furthermore, the technical features described in a given embodiment can be isolated from the other features of that embodiment unless the contrary is explicitly stated.

[0081] Detailed list of references in the figures: 1. Core 2. Collimation Structure (Collimator) 3. Coupling Structure (In-coupling) 10. First sheet (Foil 1) 11. Second sheet (Foil 2) a. Size of the management system (MS)

[0082] S. Size of the light source

[0083] SG Light Management System (SG)

[0084] LGP Light guide plate

[0085] d. Distance between the source and the Management System (MS) t. Thickness of the light guide plate (LGP)

Claims

Demands

1. A light management system (SG) comprising illumination achieved using uncollimated light directed towards a flexible light guide plate (LGP) comprising a core (1) in the form of a light-transmitting sheet; Characterized in that it comprises: - A first film (10) adjacent to a first face of the core (1) and comprising at least one collimation structure (2) using a free-form micro-optical element (FF-MOE) design; - At least one coupling structure (3) using a prism design, preferably an air prism, on a second face of the core (1), opposite said first face; - Said collimation structure on the first film (10) directing light towards said coupling structure (3) on the second face to optimize the efficiency of light coupling in the LGP.

2. Light management system (SG) according to claim 1, wherein said coupling structure (3) is formed on a second film adjacent to said second face of the core (1).

3. Light management system (MS) according to any one of claims 1 or 2, wherein said coupling structure (3) is arranged to direct the coupled light out of an area including said collimation structures.

4. Light management system (SM) according to any one of claims 1 to 3, wherein said illumination with non-collimated light is white light illumination.

5. Light management system (LM) according to any one of claims 1 to 4, further comprising decoupling said light injected into said LGP using the same air prism structure to efficiently decouple said light.

6. Light management system (SM) according to any one of claims 1 to 5, wherein said first film (10) and core (1) form a transparent flexible film, optionally with said second film (11), the transmission of light to said opposite face of the transparent flexible film being prevented by said coupling structure (3).

7. Light management system (SM) according to claim 6, wherein said transparent flexible film has variable dimensions and in particular a height that varies from a few tens of micrometers while exhibiting optical characteristics comparable to those of conventional freeform optics which are bulky.

8. Light management system (SG) according to any one of claims 1 to 7, wherein at least the collimation structures are formed by said first film (10) which is laminated onto said core (1) or fixed thereto by an adhesive substance having a refractive index equal to or close to that of said core (1).

9. Light management system (SG) according to any one of claims 1 to 7, wherein the coupling and / or decoupling structures are laminated onto said core (1).

10. Light management system (SG) according to any one of claims 1 to 9, wherein air prism structures are disposed directly on the core material (1) instead of laminated films, to improve manufacturing efficiency and reduce material consumption.

11. Method of manufacturing a light management system (SM), usable with non-collimated light, by creating optical structures on a flexible light guide plate (LGP), said method comprising the following steps: - Creation of a master impression using greyscale lithography to produce optical patterns on a surface; - Printing optical patterns on a first film (10) using direct UV printing based on the master impression, to obtain at least one collimation structure (2) forming a first optical structure, using a design of free-form micro-optical elements (FF-MOEs);- Printing optical patterns on a second film (11) using direct UV printing based on the imprint master or the arrangement of air prism structures directly on a core (1) of a flexible light guide plate (LGP), to obtain at least one coupling structure (3) forming a second optical structure; - Assembly of the films and the core (1) to form a flexible LGP comprising optical patterns and / or air prism structures, with a collimation structure (2) on one face of the core (1) and a coupling structure (3) on the other face.

12. A method according to claim 11, further comprising laser writing processes for the creation on a master, called origination, and the reproduction, called replication, on a target substrate such as a film, of said optical structures in order to ensure precise and personalized patterns.

13. A method according to any one of claims 11 or 12, further comprising a roll-to-roll replication process for optical printing.

14. A method according to any one of claims 11 to 13, further comprising manufacturing a batch of films printed with the structure designed by the origination, among said optical structures, and then a replication process by UV printing.

15. A method according to any one of claims 11 to 14, wherein the impression master is designed to produce optical patterns on film sheets in order to improve the efficiency of light coupling and decoupling in the flexible light guide plate.

16. A method according to any one of claims 11 to 15, wherein the greyscale lithography is carried out using a specialized lithography mask to create subtle variations of greyscale on the impression master.

17. A method according to any one of claims 11 to 16, wherein direct UV printing is carried out by selectively exposing a photosensitive material on the film sheet to a UV light source through the impression master.

18. A method according to any one of claims 11 to 17, wherein said assembly is made by optical bonding using adhesive materials having a refractive index corresponding to that of the first film (10) used to obtain said collimation structure and / or of the core and / or of the second film (11) used to obtain said air prism structure.

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