Optical structure with light guide
By using a combination structure of light guide and protective layer in the motor vehicle lighting system, and by taking advantage of the refractive index difference and fully filled interface, the problems of low optical efficiency and visible decorative elements are solved, achieving efficient light-emitting patterns and beautiful appearance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- VALEO VISION SA
- Filing Date
- 2024-10-10
- Publication Date
- 2026-05-08
AI Technical Summary
Existing vehicle lighting systems have low optical efficiency when activated and decorative elements are visible when deactivated, affecting aesthetics.
The structure employs a combination of a light guide and a protective layer, wherein the light guide is made of a first material and the protective layer is made of a second material, with a refractive index difference between the two between 0.1 and 0.3, forming a fully filled interface. A decoupling element on the rear surface of the light guide redirects the light to the front surface, ensuring that reflection at the interface between the light guide and the protective layer is minimized.
Achieving highly optically efficient luminescent patterns when the light source is activated, and making the decoupling elements and decorative layers invisible when the light source is turned off, thus enhancing the aesthetic effect.
Smart Images
Figure CN122003564A_ABST
Abstract
Description
[0001] The field of this invention is the field of optical structures, and particularly the field of optical structures for motor vehicles, including light guides for directing light and illuminating, for example, body parts, protective external lenses (such as the external lenses of headlights or taillights), or the internal surfaces of motor vehicles.
[0002] To give vehicles specific luminous characteristics or create a luminous environment in the passenger compartment, it is increasingly common to introduce luminous systems that allow luminous patterns to be produced when the light source of the luminous system is activated. For visual effect, it is desirable that the luminous patterns, or even the luminous system itself, be invisible when the light source is off. Therefore, the luminous patterns only appear when the light source is activated.
[0003] Therefore, decorative elements are typically placed on top of the light-emitting system. Thus, the decorative elements conceal the light-emitting system, making the pattern invisible when the system is off. However, when the light-emitting system is activated, the decorative elements cut off some of the light emitted by the system, which reduces the optical efficiency of the system.
[0004] Therefore, there is a need to provide a light-emitting system that allows for the generation of light-emitting patterns with better optical efficiency when turned on, and is invisible when turned off.
[0005] Therefore, one subject of the present invention is an optical structure, particularly an optical structure for motor vehicles, the optical structure comprising: - An optical guide having decoupling elements on its rear surface, these decoupling elements being configured to redirect light guided by the optical guide to a front surface opposite to the rear surface of the optical guide, the optical guide being made of a first material having a first refractive index (n1). - A protective layer covering the decoupling element on the rear surface of the light guide. The protective layer is transparent and is made of a second material having a second refractive index (n2).
[0006] In the optical structure, the first refractive index (n1) is greater than the second refractive index (n2), the difference between the first refractive index (n1) and the second refractive index (n2) is between 0.1 and 0.3, and the contact between the light guide and the protective layer forms a completely filled interface, so that the decoupling element is invisible when no light is incident on the light guide.
[0007] A layer with a high transmittance is called a "transparent layer" (especially in the context of transparent protective layers). If the inherent transmittance of the layer is taken into account, then the layer can be considered transparent when its transmittance is greater than 95% or 99%. The inherent transmittance of the layer is determined by neglecting Fresnel reflection at its interface, which depends on the refractive index of the adjacent material. If the transmittance of the layer in air is taken into account, then the layer can be considered transparent when its transmittance is greater than 85% or 90%.
[0008] When light is introduced into the light guide, the decoupling element allows the formation of one or more luminescent patterns. With the decorative layer and protective layer positioned face-to-face, light does not need to pass through the decorative layer to leave the optical structure (because the decoupling element is configured to redirect light guided by the light guide to the front face of the light guide opposite to the rear face of the receiving protective layer), which imparts good optical efficiency to the optical structure.
[0009] In this invention, the difference between the first refractive index (n1) and the second refractive index (n2) is advantageously chosen to be greater than 0.1 so as to ensure that light incident on the light guide is guided through the light guide by total internal reflection, and less than 0.3 so that light from the environment outside the optical structure is deflected as little as possible by refraction at the interface between the light guide and the protective layer.
[0010] In addition, the contact between the light guide and the protective layer forms a completely filled interface.
[0011] A fully filled interface refers to an interface that contains no air or air bubbles. This fully filled interface prevents parasitic reflections at the interface between the light guide and the protective layer, which would otherwise allow the decoupling pattern to be visible. A fully filled interface is achieved by directly bonding the two components at the interface.
[0012] Therefore, the interface between the light guide and the protective layer is airless, which allows for the minimization of light deflection at the interface between the light guide and the protective layer.
[0013] By utilizing the difference between the first refractive index (n1) and the second refractive index (n2) and the fully filled interface between the light guide and the protective layer, the decoupling element is made invisible when no light is incident on the light guide, as will be described in more detail below.
[0014] According to one aspect of the invention, the light guide has an interface with air at its front surface. In other words, the light guide has no additional protective layer on its front surface. Therefore, light from the light guide is directly emitted into the world outside the light guide. In other words, light from the light guide will not pass through other elements once it leaves the light guide. Thus, the optical efficiency of the optical structure is maximized.
[0015] Additionally, even when no light is incident on the light guide (in the off state), ambient light may be reflected. These reflections may occur particularly at the interface between the air and the light guide, and at the interface between the light guide and the protective layer. The reflection at the interface between the light guide and the protective layer is not very visible because the difference in refractive index between the light guide and the protective layer is small. Reflections from the interface between the air and the light guide (which corresponds to reflections from an unpatterned surface) are also not very visible. Therefore, even when no light is incident on the light guide, it is visible through the light guide and the protective layer. In other words, the stack of the light guide and the protective layer appears transparent. In particular, the decoupling elements (like the luminescent patterns they produce) are invisible or not very visible. Therefore, the decorative layer can be placed facing the protective layer. Thus, the strongest reflections will be at the interface between the protective layer and the decorative layer, especially from one side of the decorative layer. This side of the decorative layer can be, for example, a uniform surface, or optionally, a design forming a decorative pattern. Therefore, the present invention enables a satisfactory aesthetic effect when only the decorative layer is visible while the light guide is exposed to ambient light.
[0016] According to one aspect of the invention, the light guide receives an additional protective layer on its front surface.
[0017] Where appropriate, the additional protective layer may have a first side that contacts the light guide, particularly the front surface of the light guide, and a second side opposite to the first side, which has an interface with air.
[0018] Advantageously, the additional protective layer has a refractive index that is different (preferably slightly different) from that of the light guide. For example, the difference between the first refractive index and the refractive index of the additional protective layer is between 0.1 and 0.3. In a particular example, the additional protective layer has the same optical index as the protective layer. Therefore, light is guided through the light guide by total internal reflection, and light leakage associated with the presence of dust is avoided. Since the light is guided within the light guide, rather than within the additional protective layer (due to the difference in refractive index), this leakage is avoided. The additional protective layer thus forms a protection between the light guide and the dust, and the dust (which can act as a decoupling element) does not come into contact with the light guided within the light guide. Furthermore, the small difference in refractive index minimizes any reflection at the interface between the additional protective layer and the light guide. Therefore, the decorative layer can be placed opposite the protective layer such that, in the absence of light incident into the light guide, the decorative layer, and in particular one side of the decorative layer, is visible through the additional protective layer, the light guide, and the protective layer.
[0019] According to one aspect of the invention, the contact between the light guide and the additional protective layer forms a fully filled interface.
[0020] According to one aspect of the invention, the light guide is formed of a transparent material.
[0021] According to one aspect of the invention, the light guide is formed of a material selected from polyurethane, polycarbonate, polymethyl methacrylate, or glass. It is particularly advantageous to make the light guide from polyurethane when the optical structure does not have an additional protective layer. Specifically, polyurethane allows light to be both guided through the light guide and protected from the influence of the external environment.
[0022] According to one aspect of the invention, the protective layer is formed of a material selected from the following: silicone, polyethylene, polymethyl methacrylate, or a nanocomposite coating.
[0023] According to one aspect of the invention, the thickness of the transparent protective layer is less than 10 mm, preferably less than 5 mm, or even less than 1 mm. Therefore, if the decorative layer is placed opposite the protective layer, such a small thickness advantageously prevents the decorative layer from being positioned too far from the rear surface of the light guide, which would degrade the appearance of the decorative layer (in the closed state of the optical structure).
[0024] According to one aspect of the invention, the first material and the second material form one of the pairs of materials (first material / second material) in the following list: - Polymethyl methacrylate / nanocomposite coating - Polycarbonate / polymethyl methacrylate - Polycarbonate / Silicone - Polycarbonate / nanocomposite coating - Polyurethane / Silicone - Polyurethane / Polyethylene - Glass / Silicone - Glass / nanocomposite coating.
[0025] According to one aspect of the invention, the decoupling elements in the light guide are formed from inclined or curved facets or rough facets, for example, by cutting, molding, ablation (e.g., laser ablation), or pressing. These decoupling elements make it possible to create one or more light-emitting patterns, for example, by grouping decoupling microstructures in the light guide. These light-emitting patterns are visible when light is incident on the light guide.
[0026] According to one aspect of the invention, the decoupling element comprises a microstructure that may have different shapes.
[0027] According to one aspect of the invention, the decoupling element has a height of less than 500 micrometers, particularly less than 200 micrometers or less than 100 micrometers.
[0028] According to one aspect of the invention, the protective layer is a material overmolded onto the light guide.
[0029] According to one aspect of the invention, the protective layer has a thickness greater than 5 µm, preferably equal to 10 µm.
[0030] According to one aspect of the invention, the protective layer is a coating having a low refractive index (e.g., a refractive index of 1.35).
[0031] According to one aspect of the invention, the light guide and protective layer are produced using a 2K molding process. This molding process is specifically performed using a mold that includes at least two cavities A and B in its movable portion. The injection is performed in two stages. In the first stage, cavity A faces the fixed portion of the mold, and a first material is injected. Subsequently, the part remains in the fixed portion, the movable portion moves to present cavity B (typically this is done by rotating the mold), and a second material is injected. Thus, a one-piece part is obtained using two different materials. Of course, other methods can be used.
[0032] According to one aspect of the invention, the optical structure includes a decorative layer that is placed over the protective layer of the optical structure and is visible through the front surface of the light guide, through the protective layer of the optical structure, and through the light guide when no light is incident into the light guide.
[0033] According to one aspect of the invention, the decorative layer and the protective layer form a completely filled interface. This is advantageous, particularly when the optical structure is intended to form at least a portion of a motor vehicle component (such as a trim piece for the passenger compartment or body section of a motor vehicle). Specifically, avoiding air between the decorative layer and the protective layer ensures the hue of the optical structure can be maintained even in the absence of incident light. This prevents Fresnel loss at the interface and prevents the light guide from being seen. Therefore, the appearance of the optical structure in the closed state is improved.
[0034] According to one aspect of the invention, the decorative layer may be a paint coating, a print formed with ink, a deposit formed by physical vapor deposition (PVD), or a surface plated with chromium using an electrolytic process.
[0035] According to one aspect of the invention, the light guide is rigid, for example, for integration into the outer lens of a headlight or body section of a motor vehicle. In particular, the light guide may optionally deform only when subjected to stress. For example, if a force is applied to each end of the light guide, the light guide may be slightly bent.
[0036] According to one aspect of the invention, the light guide may have a thickness greater than or equal to 1.5 mm, preferably greater than or equal to 3 mm.
[0037] According to one aspect of the invention, the light guide can form at least a portion of a motor vehicle component (such as the enclosed outer lens of a motor vehicle's headlight or taillight, or a body panel or passenger compartment trim). According to this aspect, the light guide itself forms part of the vehicle component. It does not need to be pre-positioned on a carrier for subsequent fastening to the vehicle component.
[0038] As a variant, the light guide is flexible / flexible. The entire optical structure can be flexible / flexible. In this variant, it is necessary to position the light guide, or even the optical structure, on a rigid support so that it can be integrated into vehicle components.
[0039] According to one aspect of the invention, the front and rear surfaces of the light guide are parallel.
[0040] Another subject of the present invention is a light-emitting system comprising: - As described above, the optical structure - A light source configured to incident light into a light guide via an incident region configured such that the incident light is guided through the light guide and reflected by a decoupling element on the rear surface of the light guide, particularly towards the front surface of the light guide.
[0041] Because the light is guided through the light guide and reflected by the decoupling element, the light does not pass through the decorative layer.
[0042] According to one aspect of the invention, the light source is located outside the optical structure.
[0043] According to one aspect of the invention, light rays delivered by a light source are reflected (while remaining in the light guide) by the surface of the light guide to decoupling elements, which guide these light rays toward the interface between the front surface of the light guide and the air, such that the light rays leave the light guide with an intensity distribution controlled by the shape of the decoupling elements.
[0044] According to one aspect of the invention, the shape of the decoupling element is configured to produce a Lambertian or quasi-Lambertian distribution of light rays leaving the light guide, which is advantageous for opening the appearance because the light-emitting pattern produced by the decoupling element is visible in all directions with the same intensity, i.e., regardless of the position of the eye.
[0045] As a variant, the shape of the decoupling element is configured to produce a narrower angle of light intensity distribution, which allows for good photometric efficiency in one or more specific directions (also known as preferred directions). This can be particularly advantageous when the optical structure is involved in performing a signaling function, and when regulations require that the signaling function to be efficient in one or more specific / preferred directions.
[0046] According to one aspect of the invention, the light-emitting system is configured to participate in performing a signaling function. The signaling function may be, for example, a daytime running light function, a position light function, or a turn signal function.
[0047] According to one aspect of the invention, the light guide includes an inner surface on which light is reflected.
[0048] According to one aspect of the invention, the light source and one of the surfaces of the light guide are positioned face to face, such that light emitted by the light source penetrates into the light guide.
[0049] According to one aspect of the invention, the light source and the light guide are positioned face-to-face in the area outside the protective layer.
[0050] According to one aspect of the invention, the light-emitting system includes an opaque insert that allows the light source to be hidden in order to block direct light from the light source. This opaque insert makes it possible to conceal unsightly technical areas.
[0051] According to one aspect of the invention, the rear surface of the light guide includes a coupling region for coupling light to the light guide and positioning it in front of the light source.
[0052] According to one aspect of the invention, the coupling region may have a planar shape, a conical shape, a lens shape, or a collimator shape.
[0053] According to one aspect of the invention, the decorative layer is placed on the side of the protective layer opposite to the side against which the light guide is placed, and preferably outside the coupling region.
[0054] According to one aspect of the invention, the light guide has an inclined surface that forms an acute angle with the coupling region and is positioned facing the light source to reflect light propagating through the light guide in the direction of the decoupling element by total internal reflection.
[0055] According to one aspect of the invention, the decoupling element is placed outside the coupling region.
[0056] According to one aspect of the invention, an opaque insert is placed on the periphery of the light guide.
[0057] According to another aspect of the invention, the light guide includes a coupling region substantially perpendicular to adjacent edges of the light guide, and the light source is positioned facing the coupling region such that light is incident through the coupling region.
[0058] According to one aspect of the invention, the rear face includes a main region, particularly a curved main region, on which a decoupling element is formed.
[0059] According to one aspect of the invention, the radius of curvature of the curve in the main region is at least five times the thickness of the optical guide.
[0060] According to one aspect of the invention, the rear face includes an extended region offset in the thickness direction, and the extended region engages with the lateral face.
[0061] According to one aspect of the invention, the extended region and the complementary opposite side of the light guide form a light incident region.
[0062] According to another aspect of the invention, the light guide includes a bent section defining a light incident region and a main section engaging with the bent section. The main section, on which decoupling elements are formed, is particularly bent.
[0063] According to one aspect of the invention, the bent section is curved, particularly having an arcuate profile.
[0064] According to one aspect of the invention, the light source is positioned facing the end face of the bent section and outside the protective layer.
[0065] According to one aspect of the invention, the protective layer extends on the main section and the bent section.
[0066] According to one aspect of the invention, the light incident region has a shape with a reduced angular aperture that allows light rays to propagate through the light guide, the angular aperture particularly having a conical shape, a lens shape, or a collimator shape.
[0067] According to one aspect of the invention, the light-emitting system is used to illuminate a body part, a protective outer lens of a light-emitting device (such as a headlight or taillight), or an inner surface of the vehicle.
[0068] Another subject of the invention is a motor vehicle component comprising an optical structure including a rigid light guide that forms at least a portion of the vehicle component. The term "motor vehicle component" should be understood to mean an element intended to form part of a motor vehicle (particularly a structure of a motor vehicle). For example, a motor vehicle component may be a closed outer lens of a headlight or taillight of a motor vehicle, or a trim piece of a body section or passenger compartment.
[0069] Further features, details, and advantages of the invention will become clearer, on the one hand, by reading the following description, and on the other hand, by referring to the numerous non-limiting examples of embodiments given by way of illustration in the accompanying illustrative drawings, in which: [ Figure 1A ] Figure 1A A schematic perspective view of an example light-emitting system according to an embodiment of the present invention is shown, the light-emitting system being in an on state and including an optical structure that allows the formation of a light-emitting pattern; [ Figure 1B ] Figure 1B The screen is shown as closed. Figure 1A A schematic three-dimensional diagram of the light-emitting system; [ Figure 2 ] Figure 2 A first embodiment of the light-emitting system according to the present invention is shown schematically in cross-section; [ Figure 3 ] Figure 3 A second embodiment of the light-emitting system according to the present invention is shown schematically in cross-section; [ Figure 4 ] Figure 4 A third embodiment of the light-emitting system according to the present invention is shown schematically in cross-section; [ Figure 5 ] Figure 5 A fourth embodiment of the light-emitting system according to the present invention is shown schematically in cross-section.
[0070] Features, variations, and forms of embodiments of the present invention can be associated with each other in a variety of combinations, provided that they are not mutually exclusive or incompatible. In particular, variations of the invention are contemplated to include only features selected and described in isolation from the other features described below, provided that such selection of features is sufficient to provide technical advantages and / or distinguish the invention from the prior art.
[0071] Figure 1A and Figure 1B as well as Figure 2 A light-emitting system 100 is shown, which includes an optical structure 10 and a light source 50, which is formed, for example, by one or more LEDs.
[0072] Optical structure 10 is an outer lens used to illuminate body parts, the inner surface of the vehicle, or even the headlights of the vehicle.
[0073] The optical structure 10 includes a light guide 40 having opposing front and rear faces 41 and 42. The front face 41 has an interface with air. In other words, in the example shown, the optical structure 10 does not have an additional protective layer placed on the front face 41 of the light guide 40.
[0074] The light guide 40 has a decoupling element 60 on its rear surface 42, which is configured to redirect light emitted by the light source 50 and guided by the light guide 40 toward the front surface 41. In the described example, such as Figure 1A As shown, the decoupling element 60 is arranged to produce a diamond-shaped light-emitting pattern 61 when light is incident on the light guide 40.
[0075] The light guide 40 is rigid. Advantageously, it has a thickness of 1.5 mm or more, or even 3 mm or more. Therefore, the optical structure 10, especially the light guide 40, can form at least a part of a motor vehicle component (such as the closed outer lens of a motor vehicle's headlight or taillight, or a body part or passenger compartment trim).
[0076] Therefore, the present invention also covers motor vehicle components (such as enclosed outer lenses for headlights or taillights of motor vehicles, or trim pieces for body parts or passenger compartments) that include optical structures having rigid light guides forming at least a portion of optical elements.
[0077] The light guide 40 is made of a first material (such as transparent polyurethane) having a first refractive index (n1) similar to that of the core and coating.
[0078] As a variant, the primary material of the light guide 40 can be polycarbonate, polymethyl methacrylate, or glass.
[0079] As a variant, the light guide 40 is flexible / flexible.
[0080] The optical structure 10 includes a transparent protective layer 30 having an inherent transmittance greater than 95% or a transmittance greater than 85% when in air, ignoring Fresnel reflections at the interface. The protective layer 30 has a thickness of less than 10 mm and is made of a second material (such as silicone) having a second refractive index (n2).
[0081] As a variant, the protective layer 30 is made of polyethylene, polymethyl methacrylate, or a nanocomposite coating.
[0082] Optical structure 10 employs paired materials (first material of light guide 40 / second material of protective layer 30), such as polyurethane / silicone. The first refractive index (n1) of light guide 40 is greater than the second refractive index (n2) of protective layer 30. The difference between the first refractive index (n1) and the second refractive index (n2) is between 0.1 and 0.3. This difference is greater than 0.1 to ensure that light generated by light source 50 and incident on light guide 40 is guided in light guide 40 by total internal reflection, and less than 0.3 to minimize the deflection of light from the environment outside optical structure 10 by refraction at the interface between light guide 40 and protective layer 30, and thus make decoupling element 60 invisible, especially when light is not incident on light guide 40 by light source 50.
[0083] In the absence of an additional protective layer on its front surface 41, it is particularly advantageous to provide a polyurethane light guide. Specifically, this material not only allows light incident on the light guide to be directed, but also allows the light guide to be protected from the effects of the external environment. For example, in the event of a collision, impact, or scratch on the front surface, the polyurethane will self-heal, which prevents the light being directed in the light guide from being interrupted.
[0084] Furthermore, the contact between the light guide 40 and the protective layer 30 forms a completely filled interface, i.e., an interface that does not contain any bubbles that could generate parasitic reflections that would allow the decoupling element 60 to be seen. This helps to make the decoupling element 60 invisible when no light is incident on the light guide.
[0085] As a variant, the paired materials (the first material of the light guide 40 / the second material of the protective layer 30) are polymethyl methacrylate / nanocomposite coating, polycarbonate / polymethyl methacrylate, polycarbonate / silicone, polycarbonate / nanocomposite coating, polyurethane / polyethylene, glass / silicone, or glass / nanocomposite coating.
[0086] The optical structure 10 also includes a decorative layer 20. The decorative layer 20 is positioned facing the protective layer 30 and is visible through the protective layer and the front surface 41 of the light guide 40 when no light is incident into the light guide 40.
[0087] In this example, the contact between the decorative layer 20 and the protective layer 30 forms a fully filled interface.
[0088] The decorative layer 20 is, for example, uniform in appearance throughout its entirety. As a variation, the decorative layer 20 may have a characteristic design, such as a logo, also known as a decorative pattern. It should be understood that the choice of decorative pattern is independent of the choice of the luminescent pattern 61 formed by the decoupling element 61. In other words, the decorative pattern may have the same shape as the luminescent pattern 61 or a different shape, depending on the desired appearance of the luminescent system 100 in both the off state (i.e., when the light source 50 associated with the light guide 40 is off) and the on state (i.e., when the light source 50 associated with the light guide 40 is on).
[0089] Light source 50 is configured to direct light into light guide 40 via an incident region, which is configured such that the incident light is guided through light guide 40. In the example shown, only one light source 50 is shown; it should be understood that multiple light sources may be present for directing light into the light guide. In this case, the light guide may have a single incident region or multiple incident regions to allow light emitted by the light source to be incident into the light guide 40. The rear surface 42 of the light guide 40 includes a decoupling element 60 for reflecting light. Because the light is guided through the light guide 40 and reflected by the decoupling element 60, the light does not pass through the decorative layer 20.
[0090] The light source 50 is located outside the optical structure 10 and positioned face-to-face with one of the surfaces of the light guide 40, such that light emitted by the light source 50 penetrates into the light guide 40 outside the protective layer 30. Light rays 51 from the light source 50 are reflected by the inner surface of the light guide 40 to decoupling elements 60. These decoupling elements 60 guide them toward the interface between the front surface 41 of the light guide 40 and the air, such that the light rays 51 exit the light guide 40 with an intensity distribution controlled by the shape of the decoupling elements 60. The shape of the decoupling elements 60 is configured to produce a Lambertian distribution of the light rays 51 exiting the light guide 40, which enables good visibility.
[0091] As a variant, the intensity distribution of the light 51 leaving the light guide 40 is almost Lambertian.
[0092] As a variant, the shape of the decoupling element 60 produces the intensity distribution of the light ray 51 in a narrower angle, thereby allowing for good photometric efficiency.
[0093] A primary reflection occurs at the first interface between the air and the light guide 40, and a secondary reflection occurs at the internal interface between the light guide 40 and the protective layer 30. Because the difference in refractive index between the light guide 40 and the protective layer 30 is very small, this secondary reflection is substantially weaker than the primary reflection, and as a result, it is extremely difficult to perceive, making the decoupling element 60 invisible. However, this primary reflection is still less visible than the primary reflection formed by the interface between the decorative layer 20 and the light guide 40. Therefore, when no light from the light source 50 is transmitted to the light guide 40, the decorative layer 20 is visible, especially through the light guide 40 and the protective layer 30.
[0094] The protective layer 30 is a material overmolded onto the optical guide 40. Both components are manufactured using a 2K molding process. The protective layer 30 has a thickness greater than 5 µm.
[0095] As a variant, the light guide 40 incorporates an additional protective layer on the front surface of the light guide.
[0096] The decoupling element 60 is formed by an inclined facet created by cutting.
[0097] As a variant, the decoupling element 60 is formed from curved or rough facets. They have a height of less than 500 micrometers and include microstructures that can have different shapes.
[0098] As a variant, the decoupling element 60 is formed by facets produced by molding, laser ablation, or pressing.
[0099] exist Figure 1A In the middle, the light-emitting system 100 is turned on (the light source 50 emits light), and the diamond-shaped light-emitting pattern 61 generated by the decoupling element 60 is visible.
[0100] exist Figure 1B In the middle, the light-emitting system 100 is turned off (the light source 50 does not emit light and there is ambient light), and the diamond-shaped light-emitting pattern 61 generated by the decoupling element 60 is not visible; only the decorative layer 20 (which has a uniform appearance) is visible.
[0101] Different embodiments of the light-emitting system 100 will now be described, and these embodiments are... Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown in the figure. These embodiments differ primarily in the shape of the light guide.
[0102] exist Figure 2 In a first embodiment of the light-emitting system 100 shown, the light guide 40 includes an opaque insert 70 placed around the periphery of the light guide 40 and allowing the light source 50 to be concealed to block direct light from the light source. The opaque insert 70 allows unsightly technical areas to be hidden.
[0103] The light guide 40 has a planar coupling region 62 located on its rear surface 42. This coupling region 62 allows light to be coupled to the light guide 40 and is positioned in front of the light source 50.
[0104] As a variant, coupling region 62 is in the shape of a lens or collimator.
[0105] The decorative layer 20 is placed on the surface of the protective layer 30 opposite to the surface against which the light guide 40 is placed, and outside the coupling region 62.
[0106] The light guide 40 has an inclined surface 43 that forms an acute angle with the coupling region 62 and is positioned facing the light source 50 to reflect light propagating through the light guide 40 in the direction of the decoupling element 60 by total internal reflection. The decoupling element is placed outside the coupling region 62.
[0107] exist Figure 3 In a second embodiment of the light-emitting system 100 shown, the light guide 400 includes a coupling region 620 perpendicular to adjacent edges of the light guide 400. The light-emitting system 100 also includes a light source 50 positioned facing the coupling region 620, such that light is incident through the coupling region 620.
[0108] The rear surface 420 includes a curved main region 450, the radius of curvature of which is at least five times the thickness of the light guide 400 (this curve is not shown in the figure). A decoupling element 600 is formed in this main region 450. The rear surface 420 also includes an extension region 460 offset in the thickness direction, and this extension region 460 engages with the lateral surface 440. This extension region 460 forms a light incident region with the complementary opposite surface 470 of the light guide 400.
[0109] exist Figure 4 In a third embodiment of the illustrated light-emitting system 100, the light guide 700 includes a bent section 760 that is arched and has an arcuate profile defining a light incident area. The light guide 760 also includes a main section 750 that engages the bent section 760. A decoupling element 800 is formed on the bent main section 750.
[0110] The light-emitting system 100 has a protective layer 300 extending on the main section 750 and the bent section 760.
[0111] The light source 50 is positioned facing the end face of the bent section 460 and outside the protective layer 300.
[0112] exist Figure 5 In the fourth embodiment of the light-emitting system 100 shown, the light guide 900 has a front surface 910 and a rear surface 920 that are parallel to each other. These surfaces receive corresponding protective layers 915 and 925. Therefore, unwanted light decoupling caused by the presence of dust can be prevented.
[0113] The light guide 900 has a tapered light incident area 950, which allows for a reduction in the angular aperture of light propagating through the light guide 900.
[0114] As a variant, the incident region 950 can be in the shape of a lens or collimator.
Claims
1. An optical structure (10), particularly an optical structure for motor vehicles, said optical structure comprising: - A light guide (40) having decoupling elements (60) on its rear surface (42) configured to redirect light guided by the light guide to a front surface (41) opposite to the rear surface of the light guide (40), the light guide (40) being made of a first material having a first refractive index (n1). - A protective layer (30; 300) covering the decoupling element (60) on the rear surface (42) of the light guide (40), the protective layer (30) being transparent and made of a second material having a second refractive index (n2), The first refractive index (n1) is greater than the second refractive index (n2), the difference between the first refractive index (n1) and the second refractive index (n2) is between 0.1 and 0.3, and the contact between the light guide (40) and the protective layer (30; 300) forms a completely filled interface, such that the decoupling element (60) is invisible when no light is incident on the light guide (40).
2. The optical structure (10) as described in claim 1, wherein, The light guide (40) has an interface with air at its front surface (41).
3. The optical structure (10) as described in claim 1, wherein, The light guide receives an additional protective layer on its front surface (41), the additional protective layer preferably having a first surface in contact with the light guide and a second surface opposite to the first surface, the second surface having an interface with air.
4. The optical structure (10) as described in any of the preceding claims, wherein, The first material and the second material are formed in one of the following pairs of materials (first material / second material): - Polymethyl methacrylate / nanocomposite coating - Polycarbonate / polymethyl methacrylate - Polycarbonate / Silicone - Polycarbonate / nanocomposite coating - Polyurethane / Silicone - Polyurethane / Polyethylene - Glass / Silicone - Glass / nanocomposite coating.
5. The optical structure (10) as described in any of the preceding claims, wherein, The decoupling element (60) has a height of less than 500 micrometers, particularly less than 200 micrometers or less than 100 micrometers.
6. The optical structure (10) as claimed in any of the preceding claims, comprising a decorative layer (20) placed over the protective layer (30) of the optical structure and visible through the front surface of the light guide (40) and through the protective layer (30) and the light guide (40) of the optical structure when no light is incident into the light guide.
7. The optical structure (10) as described in the preceding claim, wherein, The decorative layer (20) and the protective layer (30) form a fully filled interface.
8. The optical structure (10) as described in any of the preceding claims, wherein, The optical guide is rigid.
9. The optical structure (10) as described in the preceding claim, wherein, The light guide has a thickness of 1.5 mm or more, preferably 3 mm or more.
10. The optical structure (10) as claimed in claim 8 or 9, wherein, The light guide can form at least a portion of a motor vehicle component, such as a closed outer lens of a headlight or taillight of a motor vehicle, or a trim piece of a vehicle body or passenger compartment.
11. A light-emitting system (100), particularly a light-emitting system for motor vehicles, said light-emitting system comprising: - The optical structure (10) as described in any of the preceding claims. - A light source (50) is configured to incident light into the light guide (40) via an incident region, the incident region being configured such that the incident light is guided through the light guide (40) and reflected by a decoupling element (60) on the rear surface of the light guide (40).
12. The light-emitting system (100) as claimed in claim 11, wherein, The light source and the light guide (40) are positioned face-to-face in the area outside the protective layer (30).
13. The light-emitting system (100) of claim 11 or 12, comprising an opaque insert (70) that allows the light source to be hidden in order to block direct light from the light source.
14. The light-emitting system (100) according to any one of claims 11 to 13, wherein, The light-emitting system (100) is configured to participate in the signal-emitting function.
15. A motor vehicle component including the optical structure of claim 10, wherein the light guide forms at least a portion of the vehicle component.