Glazing unit for a vehicle roof, lighting system and vehicle roof

Abstract

This invention relates to a glass window unit for a vehicle roof, configured to couple light into the vehicle interior for illumination and comprising a transparent or translucent roof panel. Devices for coupling light into the roof panel are disposed on its surface to couple light into the roof panel. The roof panel includes a first plate and a film-like coupling structure. The first plate is an inner sheet-like element that acts as a light guide to guide and couple light from the device into the vehicle interior. The coupling structure is located on the side of the first plate facing away from the vehicle interior. The roof panel allows the light source of the device to couple light into the first plate through the coupling structure, which includes a plurality of micromirror elements. The micromirror elements are oriented at an angle relative to the normal to the surface of the coupling structure, such that the internal reflection angle of the light coupled into the first plate is at least 74° relative to the normal to the surface of the first plate, and / or the micromirror elements are distributed in a light cone with an interior angle of at least 45° within the plane of the first plate.

Description

Technical Field

[0001] The present invention relates to a glass window unit for a vehicle roof, preferably an openable panoramic roof, sliding roof or fixed roof of a vehicle, wherein the glass window unit is configured to couple light into the interior of the vehicle for illumination.

[0002] Furthermore, the present invention relates to a lighting system for the roof of such a vehicle, comprising the aforementioned glass window unit and means for coupling light into a roof panel of the glass window unit, and to a corresponding vehicle roof. Background Technology

[0003] Traditional vehicle roof glass units are typically used in openable panoramic roofs, sliding roofs, or fixed roofs, and among other purposes, to couple light into the vehicle interior for illumination. For this purpose, such glass units typically include a transparent or translucent roof panel configured such that a device for coupling light into the roof panel (i.e., a light source) can be positioned on the surface of the roof panel facing the vehicle interior to couple light into the roof panel.

[0004] Furthermore, the roof panel typically includes a first plate and a membrane coupling structure. The first plate is an inner sheet element that serves as a light guide for guiding and coupling light from the device (i.e., the light source) into the vehicle interior. The membrane coupling structure is located on the side of the first plate facing away from the vehicle interior. The roof panel is configured such that the light source can couple light into the first plate through the coupling structure, which for this purpose includes multiple micromirror elements.

[0005] For example, WO2023144282 and US2023324598 disclose similar glass window units that employ a micromirror element coupling concept for glass laminates. For example, they disclose the use of plastic films that may contain tilted reflective surfaces or reflective particles arranged in a microprism arrangement or multiple random, grid, or stepped arrangements.

[0006] Although WO2023144282 and US2023324598 disclose the use of microprisms to couple light into a glass panel, these prior art documents do not disclose the specific shape of such microprisms, nor the specific arrangement or distribution of multiple reflective elements.

[0007] Overall, the existing technology has not solved a fundamental problem in using micromirror element systems, namely, balancing coupling efficiency with the light cone distribution generated by the micromirror element in the glass.

[0008] Micromirror element structures typically require collimated light from a light source to ensure that most of the light reflected from the micromirror element has its own angle suitable for total internal reflection in the glass plate.

[0009] For example, for glass-laminated interfaces (such as glass-PVB interfaces), due to their similar refractive indices, the angular distribution that satisfies the requirement of total internal reflection (TIR) ​​is strictly limited (approximately 74-90° relative to the glass surface normal).

[0010] To achieve such a narrow distribution of reflected light within a plane that traverses the glass and is oriented along the direction of propagation, a strongly collimated light source is required. However, collimation also results in a narrow distribution of reflected light within the plane of the glass itself. Consequently, the light cone produced by each LED within the glass is very narrow and concentrated. This is counterproductive for ambient lighting applications used for vehicle interiors, where a wide light cone is needed to achieve good color mixing and ensure uniform illumination through overlap between adjacent LEDs. Narrow light cones require more LEDs in series (and their associated costs) to ensure uniform illumination; alternatively, when using fewer LEDs, a larger mixing distance is required, which leads to a significant reduction in the area of ​​light transmission over the roof. Summary of the Invention

[0011] Therefore, the object of the present invention is to provide a glass window unit, a lighting system having the glass window unit, and a vehicle roof having the lighting system. Compared with the prior art, the glass window unit, the lighting system, and the vehicle roof can better balance the coupling efficiency and the light cone distribution generated by the micromirror element in the glass.

[0012] This objective is achieved through the subject matter protected by the independent claims.

[0013] Other advantageous embodiments and improvements of the present invention are the subject of protection of the dependent claims.

[0014] The glass window unit according to the invention is used for a vehicle roof, preferably an openable panoramic roof, sliding roof, or fixed roof of a vehicle, wherein the glass window unit is configured to couple light into the vehicle interior for illumination, the glass window unit comprising a transparent or translucent roof panel configured such that means for coupling light into the roof panel can be placed on the surface of the roof panel, preferably the surface of the roof panel facing the vehicle interior, in order to couple light into the roof panel, wherein the roof panel comprises: The first plate, which is an inner sheet-like element, serves as a light guide for guiding and coupling light from the device into the vehicle interior; and A membrane coupling structure, preferably a coupling membrane, is placed on the side of the first plate away from the vehicle interior.

[0015] The roof panel is configured such that the light source of the device, preferably one or more Top-LEDs (top light-emitting diodes), can couple light into the first panel through the coupling structure, which includes a plurality of micromirror elements. Each micromirror element is oriented at an angle α relative to the normal of the surface of the coupling structure, such that the internal reflection angle β of the light coupled into the first panel is at least 74° relative to the normal of the surface of the first panel, and / or each micromirror element is configured to distribute light in a light cone oriented at an interior angle γ of at least 45° within the plane of the first panel, preferably greater than 80°, more preferably 120°.

[0016] According to the present invention, one or more Top-LEDs are preferably used because Top-LEDs offer advantages such as a wider range of supplier choices, lower cost, and the ability to achieve higher power (higher brightness). Similarly, the glass window unit according to the present invention does not require precise alignment of the LEDs with the coupling film. Therefore, the glass window unit according to the present invention does not have the high-precision requirements for mounting optics onto the glass, which simplifies assembly and reduces costs.

[0017] Furthermore, the assembly of the coupling film in the glass and the assembly of the light source (i.e., Top-LEDs) on the glass can be performed separately during the manufacturing process. Top-LED strips can be easily installed under the film, for example, in a cover plate, without much concern about alignment issues.

[0018] Furthermore, the use of microprisms (also known as the "prism concept") described in existing technical literature (e.g., DE102020109338) requires customized LED strips, and the LEDs on the PCB (printed circuit board) must match the geometry and spacing of the prism. In contrast, according to the present invention, there are no such requirements, meaning that any top-LED strip can be used. This increases the flexibility of the system and enables the present invention to use LED strips produced or requested by different customers.

[0019] Unlike the prism concept described above, according to the present invention, any LED spacing can be used. Therefore, when manufacturing the glass window unit according to the present invention, the brightness can be easily increased or decreased simply by changing the LED strips to increase or decrease the number of LEDs.

[0020] According to the present invention, a film-like coupling structure in the form of a coupling film comprising one or more micromirror elements provides an additional improvement in illumination brightness compared to the prior art. The film-like coupling structure according to the present invention can efficiently utilize all light rays and guide them into the glass at a total internal reflection (TIR) ​​angle. This results in a significant increase in brightness (performance improvement) with the same number of LEDs, or a reduction in the number of LEDs required for the same brightness (cost savings).

[0021] According to the present invention, it may not be necessary to remove any coatings, such as low-e coatings, located on the inner surface of the glass panel. For techniques where light is initially incident on the glass at a small angle by a light source (such as prism coupling), parasitic reflections can reduce coupling efficiency or shift color coordinates because the light must first pass through the coating. This effect is offset by locally shading or removing the coating near the coupling area. However, using the glass window unit according to the present invention, and preferably in conjunction with Top-LEDs, produces vertical or near-vertical angles of incidence. At these angles, the effect of coating reflections on color and efficiency is negligible. Therefore, at least the additional complexity and cost of shading or removing the coating are reduced.

[0022] The glass window unit according to the present invention can be further improved as follows: the roof panel further includes a second plate and a laminate, the second plate being an outer sheet element that indirectly contacts the first plate through the laminate; the laminate is arranged between the first plate and the second plate, preferably the coupling structure is arranged between the laminate and the first plate.

[0023] Therefore, although the coupling structure is arranged between the first and second plates in the same way as the laminate, it can be a separate component arranged on or fixed to the laminate; alternatively, the laminate may also contain the coupling structure, rather than only containing the coupling structure arranged on the laminate.

[0024] Furthermore, the glass window unit according to the invention can be further configured such that the coupling structure is attached to the surface of the first plate facing the outside of the vehicle via a laminate and / or a transparent adhesive layer.

[0025] Furthermore, the glass window unit according to the present invention can be implemented as follows: the transparent adhesive layer is OCA (optically transparent adhesive) and / or PSA (pressure-sensitive adhesive), and its refractive index is equal to or higher than 1.48, preferably equal to 1.51 or 1.52.

[0026] In addition, the glass window unit according to the present invention can be constructed as follows: the micromirror elements are arranged in a repeating pattern in at least one direction, preferably the direction of light propagation in the light guide, and / or the micromirror elements are continuous or discontinuous, and / or the micromirror elements are linear, and / or the micromirror elements are in the form of repeating convex or concave patterns, or alternating convex or concave or serpentine patterns defined by a series of semicircles or sine curves.

[0027] In addition, the glass window unit according to the invention can be further improved as follows: the micromirror elements are in a repeating concave pattern and are configured such that the focal point is located between each adjacent micromirror element; furthermore, the micromirror elements can be staggered; in addition, the micromirror elements can have at least two different rotation angles about an axis perpendicular to the surface of the coupling structure; and, the micromirror elements can be configured to guide light in one direction (primarily), or to guide light in said one direction and another direction opposite to said one direction.

[0028] Similarly, the glass window unit according to the invention can be constructed such that the angle α of each micromirror element relative to the normal of the coupling structure surface is equal to or greater than 45°, preferably between 50° and 54°.

[0029] Furthermore, the glass window unit according to the present invention can be implemented such that, in two-dimensional space, that is, in the cross-sectional plane of the coupling structure as a coupling film, the critical distance d3* between two non-interlaced micromirror elements is expressed as a function of the micromirror angle α, the reflection coupling angle β*, and the micromirror height d2 by the following expression: d3* = d2 / tan(90°-α) + d2 / tan(90°-β*). Furthermore, the glass window unit according to the invention can be configured such that the height d2 and width d1 of each micromirror element are between 1 and 300 micrometers, preferably between 20 and 100 micrometers.

[0030] The lighting system according to the invention is used for the roof of a vehicle, preferably an openable panoramic roof, sliding roof or fixed roof of the vehicle, comprising a glass window unit according to the invention and means for coupling light into the roof panel of the glass window unit, the means being disposed on one side of the roof panel, preferably the side of the roof panel facing the interior of the vehicle, to couple light into the roof panel.

[0031] In this respect, the lighting system according to the invention can be implemented as follows: the device includes a light source comprising at least one LED, preferably a top-LED, preferably arranged on a PCB.

[0032] Furthermore, the lighting system according to the present invention can be designed such that the light source and the PCB are installed inside or hidden by the cover plate.

[0033] Additionally, the lighting system according to the invention can be configured such that light from the device is partially or fully collimated by a collimating optics device (preferably a Fresnel lens); alternatively, a corresponding incident angle κ from the light source can be generated by a vertically oriented light source and a light diffraction optics device or film (possibly in combination with the collimating optics device).

[0034] The vehicle roof according to the invention is preferably an openable panoramic roof, a sliding roof, or a fixed roof of the vehicle, which includes the lighting system according to the invention. Attached Figure Description

[0035] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings: Figure 1 A schematic cross-sectional view of a glass window unit according to the present invention is shown; Figure 2 It shows Figure 1 A plan view of the central glass window unit (in the form of a glass panel) shows an overlapping light cone with an interior angle γ; Figure 3 A top view (left side) of a coupling structure according to an embodiment of the present invention. Figure 3 (a) and cross-sectional view (right side - Figure 3 (b) The coupling structure contains multiple rows of linear, continuous tilted micromirrors or micromirror elements; Figure 4 A top view (left side) of the coupling structure according to another embodiment of the present invention. Figure 4 (a) and cross-sectional view (right side - Figure 4 (b) The coupling structure contains multiple rows of linear, tilted micromirrors or micromirror elements in two staggered patterns; Figure 5 A top view (left side) of the coupling structure according to another embodiment of the present invention. Figure 5 (a) and cross-sectional view (right side - Figure 5 (b) The coupling structure contains multiple triangular prism-shaped micromirror elements arranged in two rows of staggered patterns, so that light is reflected in equal and opposite directions; Figure 6 This is a top view of a coupling structure according to another embodiment of the present invention, which includes a plurality of linear, tilted micromirror elements arranged in an interlaced pattern and having different rotation angles about an axis perpendicular to the surface of the coupling film. Figure 7 The image shows a top view of a coupling structure according to another embodiment of the present invention, which includes tilted micromirror elements arranged in repeating convex rows, micromirror elements arranged in repeating concave rows, and micromirror elements arranged in repeating serpentine rows. Figure 8 This is a top view of a coupling structure according to another embodiment of the present invention, the coupling structure comprising tilted micromirror elements arranged in staggered, repeating concave rows, wherein the focal point of one micromirror element is located between two micromirror elements in another row in front of the micromirror element. Figure 9This is a perspective view of a coupling structure according to another embodiment of the present invention, the coupling structure comprising tilted micromirror elements arranged in a repeating serpentine pattern; Figure 10 The path of light interacting with the micromirror element is shown; Figure 11 The curve showing the relationship between the micromirror element angle α required to achieve a specific angle of light within the reflected glass and the refractive index of the adhesive is illustrated. Figure 12 The curves showing the combined relationship between the effective surface percentage of the micromirror element structure and the incident angle on the micromirror element and the angle α of the micromirror element relative to the normal are presented. Detailed Implementation

[0036] Figure 1 A schematic cross-sectional view of the glass window unit 100 according to the present invention is shown. More specifically, Figure 1 A cross-sectional schematic diagram of a glass window unit 100, which is in the form of a vehicle roof glass panel and oriented along the direction of light propagation, is shown.

[0037] In this embodiment, the glass window unit 100 according to the present invention is used for an openable panoramic roof, sliding roof or fixed roof of a vehicle.

[0038] The glass window unit 100 is configured to couple light into the vehicle interior to illuminate the vehicle interior, preferably as ambient lighting for the vehicle interior.

[0039] Therefore, the glass window unit 100 includes at least partially transparent or semi-transparent roof panels 1, 2, and 3. For example... Figure 1 As shown, a device 50 for coupling light into the roof panels 1, 2, and 3 is arranged below the roof panels 1, 2, and 3, corresponding to the side of the roof panels 1, 2, and 3 facing the vehicle interior. Thus, light can pass through the device 50 and be coupled into the vehicle interior via the roof panels 1, 2, and 3.

[0040] In this embodiment, the roof panels 1, 2, and 3 are composed of a first plate 1, a second plate 2, and a laminate 3. A coupling structure 5 is arranged on the laminate 3, which will be described in more detail below. In an alternative embodiment, the roof panels 1, 2, and 3 may include other components in addition to the above-mentioned components.

[0041] The first plate 1 is an inner sheet-like element that serves as a light guide, used to guide and couple light from the device 50 into the vehicle interior. Therefore, in this example, the first plate 1 is a light guide sheet.

[0042] The second plate 2 is an outer sheet element that is indirectly in contact with the first plate 1 through the laminate 3.

[0043] The laminate 3 is arranged between the first plate 1 and the second plate 2, and the coupling structure 5 is arranged between the laminate 3 and the first plate 1, which will be described in more detail below.

[0044] In this embodiment, the membrane coupling structure 5 is a coupling membrane placed on the side of the first plate 1 facing away from the vehicle interior. In other words, the coupling structure 5 is attached to the side of the first plate 1 facing the vehicle exterior via the laminate layer 3 and the transparent adhesive layer 7 in this embodiment.

[0045] The device 50 for coupling light to the roof panel 1 includes a light source 4 comprising one or more LEDs (one or more Top-LEDs in this embodiment), arranged on a PCB 9 in this example. Figure 1 As further shown, the light source 4 and PCB 9 are mounted inside or hidden by the cover plate 10.

[0046] Furthermore, the device 50 for coupling light into the roof panel 1 also includes a collimating optics 8, which is configured to partially or fully collimate the light from the light source 4. In this example, the collimating optics 8 is a Fresnel lens.

[0047] With the above configuration, the roof panels 1, 2, and 3 are configured such that the light source 4 of the device 50 (in this example, multiple Top-LEDs) can couple light into the first panel via the coupling structure 5, which will be described in more detail below.

[0048] The coupling structure 5 includes a plurality of micromirror elements 6, wherein each micromirror element 6 is tilted at an angle α relative to the normal of the surface of the coupling structure 5 (see, for example, see...). Figure 3 Oriented such that the internal reflection angle β of the light coupled to the first plate 1 (see, for example, see...) Figure 1 The normal to the surface of the first plate 1 is at least 74°. Furthermore, in this embodiment, each micromirror element 6 is configured to distribute light in a light cone 13 oriented at an interior angle γ of at least 45° within the plane of the first plate 1 (see, for example, [link to relevant documentation]). Figure 2 The interior angle γ is preferably greater than 80°, and more preferably 120°.

[0049] However, other specific advantageous configurations of the individual mirror elements 6 will be described in more detail below in conjunction with other embodiments of the invention.

[0050] In short, from Figure 1 As can be seen, the light 11 from the light source 4 is collimated by the collimating optical device 8, which acts as a collimator 8, and then reflected from the coupling structure 5 (i.e., the coupling film) attached to the first plate 1 by the optical adhesive 7. Subsequently, it propagates within the first plate 1 by internal reflection, and the internal reflection angle β is at least 74° relative to the normal of the plate surface.

[0051] Figure 2 A plan view of a glass window unit 100 in the form of a glass panel is shown, illustrating an overlapping light cone 13 with an interior angle γ. Furthermore, Figure 3 Top view of coupling structure 5 (i.e., coupling membrane) (left side) Figure 3 (a) and cross-sectional view (right side - Figure 3 (b) The coupling structure contains multiple rows of linear, continuous tilted micromirrors or micromirror elements 6, 6'.

[0052] Furthermore, Figure 4 A top view (left side) of coupling structure 5 (i.e., coupling membrane) is shown. Figure 4 (a) and cross-sectional view (right side - Figure 4 (b) The coupling structure comprises multiple linear, tilted micromirrors or micromirror elements 6'', 6''', arranged in two staggered rows. That is, the discontinuous micromirror elements 6'', 6''' in adjacent rows are staggered / offset in one / first direction of the coupling film, such that the micromirror elements 6'' in one row do not directly face the micromirror elements in the adjacent row in the line of sight, but rather face the next row of micromirror elements 6'' in another / second direction of the coupling film (perpendicular to the one / first direction).

[0053] from Figure 3 As can be seen in more detail, the basic geometry of the micromirror elements 6, 6' corresponds to the geometry of a prism, wherein each micromirror element 6, 6', acting as a prism, extends continuously in a first direction (i.e., the longitudinal direction of the micromirror elements 6, 6'), and this prism geometry is repeated in a second direction perpendicular to the first direction. Figure 3 In the embodiment shown, the height d2 and width d1 of each micromirror are preferably between 1 and 300 micrometers, and more preferably between 20 and 100 micrometers.

[0054] and Figure 3 different, Figure 4 The diagram shows in more detail multiple rows of smaller, independent, discontinuous micromirror elements 6'', 6'''. The next row of micromirror elements 6'', 6''' is staggered relative to the previous row. This staggered arrangement allows space between the individual micromirror elements 6'', 6''', enabling light to pass through without impacting the next micromirror element 6'', 6''' in the next row, thus allowing for closer arrangement and achieving higher efficiency through greater surface area utilization.

[0055] Figure 3 and Figure 4 Different embodiments of the invention are shown, serving as examples of coupling structures that reflect and guide light in a preferred direction. These coupling structures are suitable for vehicle roofs where the light source is positioned at the edge and the light should be directed to the center of the panel.

[0056] Figure 5 A top view (left side) of coupling structure 5 (i.e., coupling membrane) is shown. Figure 5 (a) and cross-sectional view (right side - Figure 5 (b) The coupling structure contains multiple triangular prism-shaped micromirror elements 6'', 6''', arranged in two rows of staggered patterns, so that light 11 is reflected in equal and opposite directions, which is another embodiment of the present invention.

[0057] More specifically, in Figure 5 In the implementation, an example of a coupling structure 5 is shown, which uniformly reflects light in opposite directions. This configuration is advantageous when the light source is arranged in the center of the panel and the light should be uniformly directed to the sides or front and back of the panel. For example, a centrally located light source is advantageous in reducing the number of LEDs required per unit length of roof compared to a left-right LED strip system.

[0058] According to other embodiments described below, the shape and orientation of the light cone within the glass plane can be controlled by changing the reflection direction within the glass plane. For example, this can be achieved by individually changing the orientation of each micromirror element, or by bending the reflective surfaces of the micromirror elements into a convex and / or concave shape as a whole.

[0059] In order to achieve uniform illumination while maximizing roof light transmittance, i.e. minimizing the distance required for light cone overlap, the interior angle γ of the light cone should be at least 45°, ideally greater than 80°, and more preferably 120°.

[0060] Figure 6 The diagram shows a top view of the coupling structure 5 (i.e., the coupling film), which comprises multiple linear, tilted micromirror elements 6'' arranged in an interlaced pattern and rotate at different angles about an axis perpendicular to the surface of the coupling film. This is another embodiment of the invention. The corresponding rotation of each micromirror element 6'' randomizes the direction of the light rays 11 to achieve uniform illumination and color mixing. The magnitude of the rotation angle and the distribution of different rotation angles can be varied to produce the desired light cone shape.

[0061] also, Figure 7 The image shows a top view of the coupling structure 5 (i.e., the coupling membrane), which includes inclined micromirror elements 6'''' arranged in repeating convex rows, micromirror elements 6''''' arranged in repeating concave rows, and micromirror elements 6'''''' arranged in repeating serpentine rows. This is another embodiment of the present invention.

[0062] Figure 8This is a top view of the coupling structure 5 (i.e., the coupling membrane), which includes tilted micromirror elements 6''''' arranged in staggered, repeating concave rows, representing another embodiment of the invention. The focal point 12 of one micromirror element 6''''' is located between two micromirror elements in another row in front of it.

[0063] Furthermore, Figure 9 This is a perspective view of the coupling structure 5 (i.e., the coupling membrane), which includes tilted micromirror elements 6'''''' arranged in a repeating serpentine pattern, which is another embodiment of the present invention.

[0064] Obviously, Figure 7-9 An example of a coupling structure 5 with different micromirror elements is shown.

[0065] For the convex micromirror element 6'''', the light 11 diffuses into a fan shape, forming a light cone and achieving color mixing (see...). Figure 7 (Left side micromirror element row).

[0066] For a concave micromirror element 6''''', light first converges at the focal point and then diffuses like a convex structure. The final shape of the light cone is determined by the curvature shape (see...). Figure 7 (The middle row of micromirror elements). Figure 7 The micromirror element row 6'''''' on the right side is Figure 7 The other two rows are combined in a repeating serpentine pattern (see also...). Figure 9 ).

[0067] Depending on the size of the micromirror elements, the area beneath the light source may contain dozens, hundreds, or even thousands of micromirror elements. Each micromirror element has its own "microscopic" light cone, and these light cones overlap to form a "macroscopic" light cone. This aggregate characteristic of the light cones further contributes to the good color mixing of the various rays emitted by the red-green-blue (RGB) chip inside the LED.

[0068] from Figure 8 As can be seen, another embodiment is shown, which combines several advantageous features. The repeating concave pattern allows for uniform illumination and good color mixing; the staggered arrangement leaves space between micromirror elements, allowing light to pass through without impacting the next micromirror element in the row in front of that micromirror element, thus allowing for a denser arrangement and achieving higher efficiency through higher surface area utilization; the focal point 12 of the reflection is strategically placed between the two micromirror elements in the front row to maximize this arrangement density.

[0069] To better understand the present invention, and especially the embodiments described above, the following calculations and values ​​are provided, based on the premise of an ideal collimated light source. Obviously, deviations are expected due to manufacturing tolerances of the micromirror elements, positioning tolerances during assembly, and the potential for divergence of a few degrees in actual non-ideal collimated optical devices.

[0070] When light is coupled into the glass panel and undergoes internal reflection within the internal glass light guide, the change in the direction of the light and the critical angle for total internal reflection can be determined based on Snell's law, the angle of incidence, and the refractive indices of the two materials at a given interface.

[0071] For light within the glass, the critical angle for total internal reflection is 41° relative to the surface normal at the air-to-interface and 76° relative to the surface normal at the PVB laminate-to-interface (RI = refractive index; RI = 1.52 for glass, 1.48 for PVB, and 1.00 for air). All light rays with an incident angle greater than 41° will be completely reflected at the air-to-interface but partially transmitted at the PVB-to-interface; all light rays with an incident angle greater than 76° will be completely reflected at both interfaces. Therefore, for the most efficient and uniform illumination, ideally, the final angle of reflection within the glass should be greater than 76°. While very small angles can be used, angles greater than 85° should be avoided as a general guideline. The coating on the internal glass light guide may cause a cumulative deviation in the illumination color coordinates due to interaction with the coating, which is more pronounced at angles above 85°. Therefore, the optimal target range for the internal reflection angle β is 76° to 85°.

[0072] Based on the optimal target with internal reflection angle β and the incident angle κ of the light source, the angle α of the micromirror element 6 of the coupling structure 5 (i.e. the coupling film) can be calculated.

[0073] Figure 10 The path of the interaction between light 11 and micromirror element 6 is shown. More specifically, Figure 10 A schematic cross-sectional view of the coupling structure 5 (i.e., the coupling film) containing a single micromirror element 6 is shown, illustrating the incident angle κ of the light source relative to the normal. The ratio of the effective (usable) surface area is defined as d4 / d3. The critical spacing d3* between the two elements in the plane of the coupling structure 5 (i.e., the coupling film) is expressed as a function of the micromirror element angle α, the reflection coupling angle β*, and the micromirror element height d2, by the following equation: d3*= ​​d2 / tan(90°-α) + d2 / tan(90°-β*) ---Equation (1) When the medium surrounding the coupling structure 5 (i.e. the coupling film) has the same refractive index as the internal light guide panel, β = β*.

[0074] However, in practice, the refraction of light as it transitions from the medium embedded in the coupling structure 5 (i.e., the coupling film) to the glass should be considered. In this case, the internal reflection angle β within the glass differs from the coupling angle β* after reflection from the micromirror element.

[0075] The coupling structure 5 (i.e., the coupling film) is attached to the glass surface via an adhesive layer. This adhesive can be a laminate (such as PVB) or a separate adhesive (such as OCA or PSA). The refractive index of these materials is typically between 1.48 and 1.53, preferably equal to 1.51 or 1.52. When the refractive index of the adhesive is less than that of the glass light guide, β* will always be greater than β.

[0076] Figure 11 The graph shows the relationship between the micromirror angle α required to achieve a specific angle of light within the reflected glass and the refractive index of the binder (RI 1.48–1.53). More specifically, Figure 11 The curves showing the relationship between the micromirror element angle α required to achieve a specific angle of light within the reflected glass and the binder refractive index (RI 1.48–1.53) are presented for three different incident light angles (0°, 30°, and 45°).

[0077] For reference, the critical angle for total internal reflection at the glass-PVB interface is indicated. The maximum realizable value (max) of the internal reflection angle β within the glass is also indicated.

[0078] For one possible configuration, consider an adhesive RI of 1.48 and a light source incident angle of 0°. To achieve an internal reflection angle β of 76° within the glass, the micromirror element must reflect light at a coupling angle β* of 89°, requiring an angle of approximately 45° for the micromirror element. Any micromirror element angle greater than 45° will be below the critical angle for total internal reflection (TIR) ​​and cannot achieve an internal reflection angle higher than 76°. Therefore, using the PVB laminate as both the coupling film and the adhesive for the glass is undesirable.

[0079] Consider the second possible configuration: with an adhesive RI of 1.50, a light source incident angle of 0°, and a target internal reflection angle β of 76°, the micromirror element must reflect light at a more practical coupling angle β* of 80°, which requires an angle of approximately 50° for the micromirror element. Similarly, a micromirror element with an angle of 45° would increase the maximum possible angle within the glass to 80°, which is within the optimal range of 76° to 85°.

[0080] Furthermore, an 80° angle within the glass can be achieved through a third construction, for example, with an adhesive RI of 1.52 and a micromirror element angle of approximately 50°.

[0081] Generally, increasing the refractive index of the adhesive increases the angle of the micromirror element required to achieve a total internal reflection (TIR) ​​angle; at the same time, increasing the refractive index of the adhesive also increases the maximum achievable angle within the internal glass light guide.

[0082] Figure 11 Similar curves are also given for examples with light source angles of 35° and 45°. Note that for a given adhesive refractive index, the maximum achievable inner angle does not change, but as the light source angle increases, the micromirror element angle required to achieve a given value becomes larger.

[0083] Refer again Figure 10 This diagram illustrates the path of light 11 interacting with two non-interlaced micromirror elements 6 in a two-dimensional scenario. The length of the repeating pattern (not the spacing between the elements) is given by distance d3. Only light rays that can avoid adjacent elements are usable and can be further guided into the glass panel. If adjacent elements are too close, the light rays may be blocked by the back faces of the adjacent elements. The usable length of the micromirror elements 6 is given by distance d4. Furthermore, any additional free space between the elements is also ineffective surface. Therefore, the ratio of effective (usable) surface is given by d4 / d3. The ratio of effective surface is proportional to the maximum theoretical coupling efficiency of the system.

[0084] exist Figure 10 In the example, all rays 11 reflected within the length defined by d4 will avoid the adjacent element, while all rays beyond d4 will be blocked by the adjacent element or reflected in an undesirable direction.

[0085] Clearly, there exists a critical or threshold distance for this pattern, where all light rays incident on the micromirror element 6 from top to bottom can avoid the adjacent micromirror element 6. Figure 10 The cross-sectional plane shown (two-dimensional view) Figure 10 The critical spacing d3* within the cross-sectional view is given by the above equation (1), which is a function of the micromirror angle α, the reflection coupling angle β*, and the micromirror height d2.

[0086] If the micromirror elements are too far apart, exceeding a critical distance, the ratio of effective surface area (and consequently the coupling efficiency of the system) will decrease. This is because, although the micromirror elements are fully utilized, the increased space between them does not contribute to coupling, and these rays will be lost.

[0087] If the micromirror elements are too close together and less than the critical distance, the coupling efficiency of the system remains unchanged. This is because the d4 / d3 ratio remains the same even if the distance itself is shorter. The reduction in effective surface area is compensated by an increase in the packing density of the micromirror elements (i.e., more micromirror elements per unit area of ​​coupling film, but less usable area per element).

[0088] For example, to achieve an internal reflection angle β of 76° within the glass using an adhesive with a refractive index of 1.50, the micromirror element must reflect light at a coupling angle β* of 80°, which requires the micromirror element's angle α to be approximately 50°. Using the above equation, for a micromirror element with a height of 100 micrometers, the critical spacing between non-staggered elements is 686 micrometers.

[0089] Figure 12 The curves showing the effective surface percentage (d4 / d3) of the micromirror element structure in combination with the incident angle on the micromirror element and the angle α of the micromirror element relative to the normal are presented to produce a final ray with an angle of 80° relative to the normal. It is assumed that the refractive index of the adhesive is the same as that of the glass. The corresponding incident angle κ of the light source is on the secondary axis.

[0090] For example, when the incident angle of the light source is 15°, the incident angle on the micromirror element is 10°, and when reflected from a micromirror element with an angle of 55°, the effective surface area is 20%.

[0091] More specifically, such as Figure 12 As shown, the curves illustrating the relationship between the effective surface percentage (d4 / d3) of the micromirror element structure and the combined angle κ of the light source and the angle α of the micromirror element are presented to produce a final ray with β* of 80°, where it is assumed that the refractive index of the binder is the same as that of the glass, thus β = β*. For a perpendicularly incident light source (κ = 0°), the expected percentage of effective surface (i.e., the maximum theoretical coupling efficiency) is 17%.

[0092] according to Figure 12 Increasing the angle of the light source improves the expected efficiency, but this increase is not unlimited. At higher angles (e.g., κ > 30°, especially greater than the Brewster angle (κ > 57°), losses increase due to increased reflection at the air-glass interface from the inner surface of the inner panel (the inward-facing surface). Therefore, the maximum efficiency in this example is approximately 28%.

[0093] As mentioned above and Figure 11 As shown, for a given target reflection angle inside the glass, the angle α required by the micromirror element increases with the increase of the incident angle of the light source.

[0094] According to another embodiment of the invention, for a micromirror element with an angle of 59°, combined with a light source angle of 30° and an adhesive refractive index of 1.52, the target in-angle is 80°, and the expected maximum efficiency is 23%.

[0095] As a second example of another embodiment of the present invention, when the incident angle of the light source is 15°, the incident angle on the micromirror element is 10°, and when reflected from the micromirror element at an angle of 55°, the effective surface area is 20%.

[0096] However, the angle of the light source cannot be increased indefinitely, as tilting the LED strip increases the component height. An angle of approximately 30° is a good example of a trade-off between improving efficiency and minimizing the increase in package height in the Z direction.

[0097] Alternatively, the light source itself does not need to be tilted. A tilted incident angle κ from the light source can be generated by combining a vertically oriented light source with a second light diffraction optics or film. This additional light-directing optics can be combined with a collimating optics as a single component.

[0098] The lighting system according to the invention is used for a vehicle roof, comprising the glass window unit 100 described above according to any embodiment of the invention, and the means 50 for coupling light to the roof panels 1, 2, 3 of the glass window unit 100, the means being disposed on one side of the roof panels 1, 2, 3 to couple light to the roof panels 1, 2, 3.

[0099] The vehicle roof according to the invention is preferably used for an openable panoramic roof, sliding roof or fixed roof of a vehicle, and includes a lighting system according to the invention.

[0100] The features of the invention disclosed in the foregoing description, drawings and claims are essential to the implementation of the invention, either alone or in any combination.

Claims

1. A glass window unit (100) for a vehicle roof, preferably an openable panoramic roof, sliding roof, or fixed roof, the glass window unit (100) being configured to couple light into the vehicle interior for illumination, the glass window unit (100) comprising: A transparent or translucent roof panel (1, 2, 3) is configured such that a device (50) for coupling light into the roof panel (1, 2, 3) can be placed on the surface of the roof panel (1, 2, 3), preferably on the surface of the roof panel facing the interior of the vehicle, in order to couple light into the roof panel (1, 2, 3). The roof panels (1, 2, 3) include: The first plate (1), which is an inner sheet element and serves as a light guide, is used to guide and couple light from the device (50) into the vehicle interior, and A membrane coupling structure (5), preferably a coupling membrane, is placed on the side of the first plate (1) facing away from the vehicle interior. The roof panel (1, 2, 3) is configured such that the light source (4) of the device (50), preferably one or more Top-LEDs, can couple light into the first plate (1) through the coupling structure (5), which includes a plurality of micromirror elements (6). Its features are, Each micromirror element (6) is oriented at an angle (α) relative to the normal of the surface of the coupling structure (5), such that the internal reflection angle (β) of the light coupled to the first plate (1) is at least 74° relative to the normal of the surface of the first plate (1), and / or Each micromirror element (6) is configured to distribute light in a light cone (13) oriented at an interior angle (γ) of at least 45° in the plane of the first plate (1), wherein the interior angle (γ) is preferably greater than 80°, more preferably 120°.

2. The glass window unit (100) according to claim 1, wherein, The roof panels (1, 2, 3) also include: The second plate (2) is an outer sheet element that is indirectly in contact with the first plate (1) through a laminate (3), and The laminate (3) is disposed between the first plate (1) and the second plate (2). Preferably, the coupling structure (5) is disposed between the laminate (3) and the first plate (1).

3. The glass window unit (100) according to claim 1 or 2, wherein, The coupling structure (5) is attached to the surface of the first plate (1) facing the outside of the vehicle via a laminate (3) and / or a transparent adhesive layer (7).

4. The glass window unit (100) according to claim 3, wherein, The transparent adhesive layer (7) is OCA and / or PSA, with a refractive index equal to or higher than 1.48, preferably equal to 1.51 or 1.

52.

5. The glass window unit (100) according to any one of the preceding claims, wherein, The micromirror element (6) is arranged in a repeating pattern in at least one direction, preferably the direction of light propagation in the light guide, and / or the micromirror element (6) is continuous or discontinuous, and / or the micromirror element (6) is linear, and / or the micromirror element (6) is a repeating convex or concave pattern, or an alternating convex or concave or serpentine pattern defined by a series of semicircles or sine curves.

6. The glass window unit (100) according to claim 5, wherein, The micromirror elements (6) are in the form of a repeating concave pattern and are configured such that the focal point (12) is located between each adjacent micromirror element (6).

7. The glass window unit (100) according to any one of the preceding claims, wherein, The micromirror elements (6) are arranged in an alternating pattern.

8. The glass window unit (100) according to any one of the preceding claims, wherein, The micromirror element (6) has at least two different rotation angles about an axis perpendicular to the surface of the coupling structure (5).

9. The glass window unit (100) according to any one of the preceding claims, wherein, The micromirror element (6) is configured to direct light in one direction, or to direct light in both the one direction and the opposite direction.

10. The glass window unit (100) according to any one of the preceding claims, wherein, The angle (α) of the normal of each micromirror element relative to the surface of the coupling structure (5) is equal to or greater than 45°, preferably between 50° and 54°.

11. The glass window unit (100) according to any one of the preceding claims, wherein, In the cross-sectional plane of the coupling structure (5) which serves as the coupling membrane, the critical distance (d3*) between the two non-interlaced micromirror elements (6) is expressed as a function of the micromirror angle (α), the reflection coupling angle (β*), and the micromirror height (d2) by the following expression: d3* = d2 / tan(90°-α) + d2 / tan(90°-β*).

12. The glass window unit (100) according to any one of the preceding claims, wherein, The height (d2) and width (d1) of each micromirror element are between 1 and 300 micrometers, preferably between 20 and 100 micrometers.

13. A lighting system for a vehicle roof, preferably an openable panoramic roof, sliding roof, or fixed roof, comprising: The glass window unit (100) according to any one of the preceding claims, and A device (50) for coupling light to the roof panel (1, 2, 3) of the glass window unit (100), the device being placed on the surface of the roof panel (1, 2, 3), preferably the surface of the roof panel facing the interior of the vehicle, to couple light to the roof panel (1, 2, 3).

14. The lighting system according to claim 13, wherein, The device (50) includes a light source (4) comprising at least one LED, preferably a top-LED, preferably arranged on a PCB (9).

15. The lighting system according to claim 14, wherein, The light source (4) and the PCB (9) are installed inside the cover plate (10) or hidden by the cover plate (10).

16. The lighting system according to any one of claims 13 to 15, wherein, The light from the device (50) is partially or fully collimated by the collimating optics (8), preferably a Fresnel lens.

17. A vehicle roof, preferably an openable panoramic roof, sliding roof, or fixed roof of a vehicle, comprising a lighting system according to any one of claims 13 to 16.

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