Luminescent polymer films and processes for forming same

Abstract

According to the present invention, the light-emitting polymer film is used as a complex optical system, which is applied in the structure of an edge lighting system, the entire or part of the front surface of which can emit a uniform light beam to the outside in the form of a selected pattern. The light-emitting polymer film is made of a clear and transparent polymer material by applying a spraying technology and comprises three layers which are structurally connected with one another: a contact layer (1), an active optical layer (2) and a protective layer (3). The active optical layer (2) comprises a mixture of different types of glass particles (A), (B), (C) and (D), in which the presence of each individual type of glass particles (A), (B), (C) and (D) in the structure of the active optical layer (2) is defined by the number, size and geometry thereof, the refractive index value of light and other physical properties. The contact layer (1) on one side and the final layer (3) on the other side prevent direct physical contact between the active optical layer (2) and the external environment.

Description

Technical Field

[0001] According to the present invention, the light-emitting polymer film is an innovative light-emitting product. The present invention relates to the field of optical components with light position or direction control. According to the International Patent Classification, the related inventions are marked as: G02F 1 / 29 (2006.01) and G02B5 / 02 (2006.01).

[0002] The technical problem solved by this discovery is how to form a luminescent polymer film, which is applied to the structure of an edge-lit system and whose entire front surface or part of the front surface emits a uniform light beam to the outside in the form of a selected pattern. It is colorless, optically transparent, resistant to the mechanical, temperature and chemical influences of the external environment, and resistant to the influence of solar ultraviolet radiation. Background Art

[0003] Edge lighting systems are used for backlighting of LCD screens and more recently they are being used in lighting devices. LEDs are increasingly being used in backlight assemblies to extend color, extend lifetime, improve optical efficiency and cost. However, using the same white point diffuser will scatter the light in all directions up to the critical angle of the light guide air interface. The refraction angle scattering of the light outside the light guide can reach large angles relative to the surface, in which case an optical film is needed to restore some of the light to the normal or desired viewing angle.

[0004] Other backlight configurations have been proposed by using symmetrical scattering particles instead of white dots. Okumura et al. (J. Opt. A: Pure Appl. Opt. 5 (2003) S269-S275) describe the light guide used for scattering as a polymer of "high scattering light transmission" (HSOT). The authors demonstrated that a backlight based on a HSOT polymer has the potential to provide illumination twice as great as a conventional backlight. However, the particles used are symmetrical or spherical. Okumura's teachings do not take into account the asymmetry of the incident light, nor the need to scatter more light vertically, horizontally, or outward from the main side of the light guide. In addition, conventional designs using planar light guides, such as those used in LCD screens, have limitations in terms of angular output, heat, uniformity, efficiency, and form factor. Because the light directly reaches the volume scattering area and causes uneven brightness on the light emitting surface near the edge of the light guide, the light from a light source such as an LED that falls on the volume scattering light guide can be very bright near the LED. If the diffuse intensity of the volumetric light scattering of the light guide (the angular FVHM intensity of the diffuse profile) is significantly reduced to prevent high brightness non-uniformities near the edges, the optical efficiency of the light guide will also be reduced.

[0005] US Patent US2018 / 0039009 A1 published on February 8, 2018 includes a technical solution for a display backlight device and a related display based on a design and operating principle that is substantially different from the design, application and operating principle of the present invention, according to the relevant claims, the light-transmitting particles contact the substrate or the light guide plate, which is not the case with the present invention, on the contrary, the glass particles included in the structure of the active optical layer are not in direct physical contact with the external environment. The refractive index of the light-transmitting layer in the patent application ranges from about 1.1 to about 1.3, which leads to the conclusion that the material from which the light-transmitting layer can be derived belongs to a very expensive and chemically unstable group of materials that are not resistant to the effects of solar ultraviolet radiation and other environmental influences. The light-transmitting particles have a unique spherical shape, which is not the case with the present invention - on the contrary, two of the four glass particles included in the structure of the active optical layer are proposed to have a polycrystalline shape. The front surface of the light guide plate is treated to include a concave-convex matrix, which leads to the conclusion that this is a technically complex and expensive execution process, while the present invention does not have any technical requirements for any specific treatment of the front surface. In addition, the patent application has design elements and working principles that are optimized in detail for display backlighting, and does not meet the basic technical requirements for application to interior or exterior architectures in the same manner as light-emitting polymer films are applied in interior or exterior architectures.

[0006] Patent US8033706 B1 published on October 11, 2011 describes an LED-backlit LCD whose technical solution is based on a structure involving the use of optical materials with extremely low refractive index, which leads to the conclusion that the materials constituting the structure come from a group of very expensive and chemically unstable materials that are not resistant to the effects of solar ultraviolet radiation in the long term, nor to other environmental influences; it has a matrix representation of optical elements, which leads to the conclusion that it is a technically complex and expensive implementation process, whose operating principles and structural elements are optimized for LCD backlighting, and it does not meet the basic technical requirements for use in internal or external architectures, which is different from the present invention, the structural elements of the present invention do not contain optical materials with low refractive index and matrix representation of optical elements.

[0007] Patent WO 2019 / 072938 A1 published on April 18, 2019, relates to a technical solution for a light guide plate as a lighting device, which involves the use of optical elements in the form of particles in contact with a substrate or a light guide plate, which is not the case with the present invention. On the contrary, the glass particles contained in the structure of the active optical layer are not in direct physical contact with the external environment. The claim implies the use of a photoluminescent element that emits light of a wavelength different from that of the incident light, which is not the case with the present invention. The structure of the present invention does not use an optical element that changes the wavelength of the incident light.

[0008] The US 9803819 B2 patent published on October 31, 2017 relates to a technical solution for a transparent general lighting device, which is based on the use of different categories of dielectric particles, such as metal oxides, silicates, glass beads, plastic beads, barium sulfate, inorganic phosphors, orthosilicates, aluminosilicates, nitrides, europium-doped oxynitrides, optional luminescent paint dispersions, etc. Its principle is based on the dispersion of dielectric particles in the light guide plate structure, and its function is to enable the light beam from the edge of the diffuser plate to diffuse and scatter. This is not the case with the present invention. The present invention includes four different types of glass particles with defined mutual relationships, with defined different geometric shapes and defined different refractive index values ​​of light, so that the optical interaction of these light particles with the primary light beam is not based on simple diffusion, but on complex reflections at the internal level of the structure of the light-emitting polymer film and at the external level in the relationship between the light-emitting polymer film and the external environment. In addition, the above-mentioned patent includes a technical solution that is considered to be optically transparent but not optically clear, considering the concentration of dielectric particles in the light guide plate structure, which is not the case with the present invention, in which the glass particles are generally transparent but are also completely coated with polymer materials, showing very low translucency in the visible spectrum.

[0009] According to the invention, the form of the luminescent polymer film meets all technical and safety requirements for application as functional and ambient lighting bodies in interior or exterior architectures and its operating principle is fundamentally different from the principle applied to the above-mentioned technical solutions and other similar solutions that are not listed and belong to the existing background art. Summary of the invention

[0010] According to the present invention, the light emitting polymer film is used as a complex optical system, which is applied in the structure of the edge lighting system so that its entire front surface or a certain part of its front surface can emit a uniform light beam to the outside in the form of a selected pattern.

[0011] The light-emitting polymer film is formed from a transparent, optically clear polymer material by applying a spray coating method, and has a compact structure consisting of three structurally interconnected layers, which are executed from the same polymer material: a contact layer, an active optical layer and a protective layer, wherein the contact layer on one side and the protective layer on the other side prevent direct physical contact between the active optical layer and the external environment.

[0012] The active optical layer contains a mixture of four types of glass particles, wherein the presence of each glass particle in the structure of the active optical layer is defined by its quantity, size and geometry, refractive index value of light and other physical properties.

[0013] The light-emitting polymer film can be applied to one or both front surfaces of edge-lit glass panels, rigid polymer panels, flexible polymer panels / films, on one front surface of self-adhesive polymer films, and applied independently as an insert between two thermoplastic interlayer films within the construction of two or more layers of edge-lit laminated glass. If the light-emitting polymer film has been applied to the construction of the edge-lit system so that it emits a uniform beam of light across the entire front surface, the edge-lit system can be used as a decorative ambient lighting device and / or as an optical barrier to protect privacy from outside views. If the light-emitting polymer film has been applied to the construction of the edge-lit system so that it emits a uniform beam of light in the form of a selected pattern along a portion of its front surface, the edge-lit system can be used as a decorative ambient lighting device and / or a double-sided publicity light panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention will be described in more detail below based on preferred exemplary embodiments, to which the invention should however not be limited, and with reference to the accompanying drawings, in which:

[0015] Figure 1 1. A schematic front view showing a light emitting polymer film, the front surface of which is a typical rectangular shape, as shown in the vertical section AA' and the horizontal section BB';

[0016] Figure 2 represents a light emitting polymer film which can emit a uniform light beam along its entire front surface to the external environment, as shown in the vertical section AA';

[0017] Figure 3 shows various stages of a process of forming a light emitting polymer film which, when applied to the front surface of an edge-lit background, can emit a uniform beam of light along its entire front surface, as shown in horizontal section BB';

[0018] Figure 4 shows the light distribution when a light emitting polymer film is applied to the front surface of an edge-lit substrate so that the entire front surface emits a uniform light beam to the external environment, as shown in the vertical section AA';

[0019] Figure 5 shows the various stages of a process for forming a light-emitting polymer film which, if subsequently applied in a separate process, can emit a uniform light beam along its entire front surface as an insert between two thermoplastic intermediate films which are part of the construction of a double or multilayer edge-lit laminated glazing, as shown in horizontal section BB';

[0020] Figure 6shows various stages of a process of forming a light emitting polymer film which, when applied to the front surface of an edge-lit substrate, can emit a uniform beam of light in a selected pattern along a portion of its front surface to the external environment, as shown in horizontal section BB';

[0021] Figure 7 shows a display of light distribution when a light emitting polymer film is applied to the front surface of an edge-lit substrate so that a portion of the front surface emits a uniform light beam to the outside in the form of a selected pattern, as shown in vertical section AA';

[0022] Figure 8 The various stages of the process of forming a light-emitting polymer film which can emit a uniform light beam in the form of a selected pattern to the external environment through a portion of its front surface, if subsequently applied in a separate process, as an insert between two thermoplastic intermediate films as part of the structure of a double or multilayer edge-lit laminated glass, as shown in the horizontal section BB'. DETAILED DESCRIPTION

[0023] According to the present invention, the light emitting polymer film can emit a uniform light beam to the external environment along its entire front surface, such as Figure 2 As shown in the vertical section AA'.

[0024] The luminescent polymer film is made of a transparent polymer material based on an acrylic or polyurethane binder in an organic or aqueous solvent, or a mixture of acrylic and polyurethane binders in an organic or aqueous solvent, which, due to its viscosity, is suitable for application by using a spraying technique and is optically clear and transparent. Furthermore, after polymerization, it has a fire protection class of at least B-s1-d0 according to the EN13501-1 standard, its optical refractive index value is less than 1.5, and it is long-term resistant to mechanical, thermal and chemical influences in the environment and the effects of UV radiation.

[0025] The light-emitting polymer film itself comprises three structurally connected layers: a contact layer 1, an active optical layer 2 and a protective layer 3, all of which are formed from the same polymer material.

[0026] The contact layer 1 has a thickness of 30 μm and its function is to establish contact and adhesion between the light emitting polymer film and the front surface of the edge lighting system, thereby preventing the active optical layer 2 from being in direct physical contact with the external environment.

[0027] The active optical layer 2 has a thickness of 100 μm and is located between the contact layer 1 and the protective layer 3 to prevent direct physical contact between the contact layer 1 and the protective layer 3 at any point on the surface. The active optical layer 2 comprises a mixture of four types of optically transparent glass particles A, B, C and D.

[0028] The glass particles A for external reflection are transparent spherical particles with a diameter of 35 μm or less and a light refractive index of 2.2 or more, and they occupy a volume (cm 3 ) of 6.2 g. The glass particles B for external reflection are transparent polycrystalline, preferably with a diameter of 35 μm or less and a light refractive index of 2.2 or greater, and they occupy a volume (cm 3 ) of 5.8 grams. The glass particles C for external reflection are transparent spherical particles with a diameter of 35 μm or less and a light refractive index in the range of 1.51 to 1.6. They occupy a volume (cm 3 ) of 3.1 g. The glass particles D for external reflection are transparent polycrystalline, preferably with a diameter of 35 μm or less and a light refractive index between 1.51 and 1.53, and they occupy a volume (cm 3 ) of 2.85 grams.

[0029] The protective layer 3 has a thickness of 30 μm and its function is to prevent the active optical layer 2 from coming into direct physical contact with the external environment, thereby protecting it from external influences.

[0030] The luminescent film formed according to the related invention is 85% transparent in the visible spectrum and has a translucency value of less than 2%.

[0031] The process of forming a light-emitting polymer film which, when applied to the front surface of an edge-lit substrate S, can emit a uniform beam of light along its entire front surface is carried out in several stages. Figure 3 As shown in the horizontal cross section BB' in the figure, the substrate S can be made in the form of a rigid transparent glass or polymer plate, or in the form of an elastic transparent polymer plate / film.

[0032] In preparation for the process, the front surface of the substrate C is thoroughly cleaned and degreased, and three separate liquid polymer mixtures are prepared: for the contact layer 1, for the active optical layer 2 with the addition of glass particles A, B, C and D according to the specified technical specifications, and for the final layer 3.

[0033] The first stage of the process of applying the liquid polymer mixture for the contact layer 1 is carried out by spraying the mixture as recommended over the entire front surface of the substrate S, followed by a rest period of 2-10 minutes before the next stage of the process.

[0034] The next stage of applying the liquid polymer mixture for the active optical layer 2 is carried out by spraying the entire front surface as recommended on the previously applied contact layer 1, followed by a rest period of 2-10 minutes before the next and final stage.

[0035] The application of the active optical layer 2 itself is carried out using a low-volume spray system, wherein the liquid polymer mixture for the active optical layer 2 is in a spray gun pressure container before and during application, the container having an integrated adjustable aerodynamic mixer that continuously mixes the liquid polymer mixture for the active optical layer 2, which prevents gravity sedimentation of the glass particles A, B, C and D at the bottom of the spray gun container and allows the glass particles A, B, C and D to be relatively uniformly spatially arranged in the structure of the active optical layer later.

[0036] The application of the active optical layer 2 can also be carried out using a higher volume spray system, wherein the liquid polymer mixture for the active optical layer 2 is located in a pressurized container in the preparation group before and during application, and the container has an integrated adjustable mixer before using the spray gun, which continuously mixes the liquid polymer mixture for the active optical layer 2, which prevents gravity sedimentation of the glass particles A, B, C and D at the bottom of the container and allows a relatively uniform spatial arrangement of the glass particles A, B, C and D in the structure of the active optical layer 2.

[0037] In the final stage, the liquid polymer mixture for the final layer 3 is also sprayed with the recommended thickness onto the entire front surface of the previously applied active optical layer 2, wherein in addition to the application process, a polymerization process of the applied layer also takes place, which leads to the formation of a functional luminescent polymer film.

[0038] The above-mentioned light-emitting polymer film layers were applied in a corresponding clean spray booth with appropriate filtration and ventilation, wherein the air temperature of the booth space was about 20°C.

[0039] It is recommended to carry out the layer polymerization process and formation of the light-emitting polymer film at a recommended room temperature of about 20°C for about 24 hours, or at a recommended room temperature of about 60°C for about 1 hour, or if the selected polymer mixture is suitable for UV polymerization, at a recommended room temperature of about 20°C and under electro-generated UV radiation for about 2 minutes.

[0040] When the light emitting polymer film is applied to the front surface of the edge-lit substrate S so that it emits a uniform light beam outward along the entire front surface, the light distribution is as follows: Figure 4As shown in the vertical cross section A-A' of . At least one edge of the substrate S has an electric light source mounted thereon, which generates a primary light beam L. The primary light beam L propagates through its cross section from one edge of the substrate S to its other parallel edge, optically interacting with each individual glass particle A, B, C and D within the active optical layer 2. The optical interaction of the primary light beam L with the glass particles A and B for external light reflection generates external secondary light beams LE therein, which propagate outward from the front surface of the light-emitting polymer film by forming a uniform light beam. The optical interaction of the primary light beam L with the glass particles C and D for internal reflection generates internal secondary light beams LI therein, which propagate through the cross section of the active optical layer 2 toward the surrounding glass particles. The relatively uniform spatial arrangement of the glass particles A, B, C and D within the active optical layer 2 allows the internal secondary light beams LI to be spatially uniformly distributed through the cross section of the active optical layer 2, and allows the external secondary light beams LE to be spatially uniformly distributed from the front surface of the light-emitting polymer film to the outside. The light distribution principle remains the same, with the luminescent polymer film being applied as an insert between two thermoplastic intermediate films within the structure of double or multi-layer edge-lit laminated glazing in order to emit a uniform light beam outwards along its entire front surface.

[0041] The following examples of the invention show that a light-emitting polymer film can emit a uniform light beam along its entire front surface if it is subsequently applied independently in a separate technical process as an insert between two thermoplastic intermediate films within the structure of a double or multilayer edge-lit laminated glazing. Figure 5 The process of forming the light-emitting polymer film in the horizontal cross section BB' shown is the same as the previously mentioned process, wherein the polymerization of the applied layer also occurs in the final stage of the process, after which the formed light-emitting polymer film is physically separated from the front surface of the polymer sheet / film PT, making it suitable for the structure of double-layer or multi-layer edge-emitting laminated glass. The polymer sheet / film PT has a smooth, non-stick surface and is made of a chemically stable, heat-resistant polytetrafluoroethylene material.

[0042] The following examples of the present invention show that when a light-emitting polymer film is applied to the front surface of an edge-lit substrate S, the light-emitting polymer film can emit a uniform light beam in the form of a selected pattern on a portion of the front surface thereof. The formation process of the light-emitting polymer film is as follows: Figure 6 The horizontal section BB' is shown.

[0043] The process itself, like the previous ones, consists of a preparation phase, in which the front surface of the substrate S is thoroughly cleaned and degreased, and three separate liquid polymer mixtures are prepared for the contact layer 1, for the active optical layer 2 with the addition of glass particles A, B, C and D according to the prescribed technical specifications, and for the final layer 3, wherein in the preparation phase of the process a previously prepared mask M is temporarily applied to the entire front surface of the substrate S, the mask M preferably being made of a self-adhesive polymer film, in which holes with the contour of the chosen pattern are cut on a CNC machine.

[0044] At the stage of applying the liquid polymer mixture for the contact layer 1, the liquid polymer mixture is sprayed onto the entire front surface of the mask M at a recommended thickness, where the contact layer 1 will physically contact and adhere to the front surface of the substrate S in the opening areas on the mask M, and then rest for 2-10 minutes before the next stage of the process.

[0045] At the stage of applying the liquid polymer mixture for the active optical layer 2, the liquid polymer mixture is sprayed at the recommended thickness onto the entire front surface of the previously applied contact layer 1, after which the mask M is separated from the front surface of the substrate S and then rested for 2-10 minutes before the next stage of the process.

[0046] At the final stage of the process, the liquid polymer mixture for the final layer 3 is sprayed with the recommended thickness onto the entire front surface of the substrate S, including the areas where the contact layer 1 and the active optical layer 2 were previously applied, so that polymerization of the applied layers occurs at the final stage of the process, which leads to the formation of a functional, luminescent polymer film.

[0047] The contact layer 1 and the active optical layer 2 of the light-emitting polymer film are performed in a pattern chosen so as to include only a portion of the front surface of the light-emitting polymer film, whereas the final layer 3 includes the entire front surface, making the light-emitting polymer film compact.

[0048] In the example shown, the contact layer 1 and the active optical layer 2 are implemented in the form of two vertically oriented rectangular fields and can be made in the form of any pattern (for example, as a logo, text, decorative pattern, etc.). All the technical specifications mentioned and described above for the contact layer 1, the active optical layer 2 and the final layer 3 of the light-emitting polymer film are also fully applicable to this case, which can emit a uniform light beam to the outside on part of its front surface in the form of a selected pattern.

[0049] When the light emitting polymer film is applied to the front surface of the edge-lit substrate S so that it emits a uniform light beam outward along a portion of its front surface, the light distribution is as follows: Figure 7 The light distribution in the given example is the same as the above example, where the light emitting polymer film is applied to one front surface of the edge-lit substrate S so that the entire front surface thereof emits a uniform light beam to the external environment.

[0050] The following examples of the invention show that, if subsequently applied independently in a separate technical process, as an insert between two thermoplastic intermediate films within the structure of a double or multilayer edge-lit laminated glass, a luminous polymer film can emit a uniform light beam in the form of a selected pattern over a portion of its front surface. Figure 8 The process of forming the light-emitting polymer film in the horizontal section BB' shown is the same as the process of forming the light-emitting polymer film mentioned above, wherein the polymerization of the applied layer also occurs in the final stage of the process, after which the formed light-emitting polymer film is physically separated from the front surface of the polymer plate / film PT and is therefore suitable for the structure of double or multi-layer edge-lit laminated glass.

[0051] All the above-described implementation examples of the related invention may also be modified without departing from the inventive concept of the related invention as defined in the patent claims.

Claims

1. A light-emitting polymer film made of a transparent polymer, characterized in that: The light-emitting polymer film comprises a contact layer (1), an active optical layer (2) and a final layer (3), wherein the contact layer (1) brings the light-emitting film into contact with and adheres to a surface, while the final layer (3) prevents the active optical layer (2) from coming into direct physical contact with the external environment and protects it from external influences.

2. The light-emitting polymer film according to claim 1, characterized in that The active optical layer (2) comprises a mixture of four types of optically transparent glass particles (A), (B), (C) and (D), wherein the glass particles (A) and (B) are used for external reflection of light, and the glass particles (C) and (D) are used for internal reflection of light.

3. The light-emitting polymer film according to claim 1, characterized in that The glass particles (A) and (C) are spherical in shape and have a diameter of 35 μm or less, while the glass particles (B) and (D) are polycrystalline in shape and have a particle diameter of 35 μm or less.

4. The light-emitting polymer film according to any one of claims 1 to 3, characterized in that The refractive index of light in the glass particles (A) and (B) is 2.2 or more, and the refractive index of light in the glass particles (C) and (D) is 1.5 to 1.

6.

5. The light-emitting polymer film according to any one of claims 1 to 4, characterized in that The thickness of the contact layer (1) is 30 μm, the thickness of the active optical layer (2) is 100 μm, and the thickness of the protective layer (3) is 30 μm.

6. A method for preparing a light-emitting polymer film, characterized in that: include: - a preparation phase consisting of thoroughly cleaning and degreasing the front surface of the substrate and preparing three separate liquid polymer mixtures for the contact layer (1), the active optical layer (2) and the final layer (3); - a stage of applying a contact layer (1), said contact layer (1) being applied by spraying; - a stage of applying an active optical layer (2), said active optical layer (2) being applied by spraying; - a phase of applying the final layer (3), said final layer (3) being applied by spraying; and - Phase involving the polymerization of the applied layer.

7. The method according to claim 6, characterized in that There will be a rest period of 2 to 10 minutes between coatings (1) and (2).

8. The method according to claim 6, characterized in that The air temperature in the spray booth for application of layers (1), (2) and (3) was approximately 20°C.

9. The method according to claim 6, characterized in that The polymerization is carried out at an air temperature of 20°C to 60°C and lasts for 2 minutes to 24 hours.

10. The method according to claim 6, characterized in that After polymerization, physical separation of the light-emitting polymer film is seen when applying a polymer sheet / film (PT), which is suitable for subsequent application on the structure of double or multi-layer laminated glazing.

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