Composite pane with an integrated sensor element package

Abstract

The invention relates to a composite pane (100) with an integrated sensor element (S), in particular a touch sensor with an illumination function or light sensor element, comprising at least an outer pane (1) and an inner pane (2) which are connected together via a thermoplastic intermediate layer (3), wherein the sensor element (S) is provided at least on an active end of a printed circuit board between the outer pane (1) and the inner pane (2) in an opening in the intermediate layer (3), and the sensor element (S) at the active end is designed as a sensor element package (10) which comprises electronic SMD components, including at least one LED (4) and a diffuser (D) which is located over the LED (4) in the emission direction thereof and which is provided on a printed circuit board (5) and is connected thereto, said SMD components and printed circuit board (5) being enclosed at the active end by a frame-shaped casing (8). The invention additionally relates to a method for producing such a composite pane and to the use thereof.

Description

[0001] Composite pane with integrated sensor element package

[0002] The invention relates to a composite pane with an integrated electronic sensor element, in particular with a sensor element comprising an integrated capacitive touch sensor with illumination or a light sensor element, a method for its production and its use.

[0003] In motor vehicles, the detection of environmental conditions or parameters is playing an increasingly important role for safe and efficient operation. Modern cars are therefore equipped with a multitude of sensors that record relevant environmental conditions or parameters and transmit the current values ​​to processing and control units that manage the vehicle's functions. This applies not only to motor vehicles, but also, to a certain extent, to certain watercraft, rail vehicles, and aircraft.

[0004] Certain sensors can be advantageously installed on or in the windshield, or possibly also the rear window, side windows, or a glass roof unit of a car. Similar arrangements are known, for example, for rain sensors that control the vehicle's windshield wiper functions. As part of the general trend toward the largely complete prefabrication of vehicle components, there are developments aimed at integrating corresponding sensors into a prefabricated glazing unit (e.g., the windshield or rear window) of a vehicle. Corresponding solutions are mentioned in WO2019057574.

[0005] Vehicle windows with integrated or partially integrated sensors are also known from EP2121308B1. DE102004054465 A1 discloses an optical moisture sensor for detecting moisture on the outside and / or inside of a vehicle window. This sensor is integrated into the PVB film used to bond the two panes of the laminated glass pane together. Furthermore, WO 2015 / 162107 A1 discloses a glass panel with an illuminated button and heating function.

[0006] WO 2019 / 150037A1 discloses an OLED functional module on a circuit board within a composite pane, which is attached to one of the glass panes via a plastic tape. Similarly, WO 2017 / 103426A1 discloses an OLED functional module on a circuit board within a composite pane. DE202015009229U1 and DE102013003686A1 disclose LED functional elements on circuit boards within a composite pane. WO2017097536A1 discloses photodiodes on a circuit board within a composite pane.

[0007] To facilitate light diffusion from lighting elements such as LEDs, the conductor tracks with which the LEDs are contacted are often embedded as flexible circuit boards in the surrounding clear PVB interlayer in laminated panes. To conceal the conductor tracks, they are usually covered with a black or white masking print, and the light from the LED is emitted primarily through a designated cutout in this masking print (black print). A diffuser, such as a PDLC film, arranged around the active part of the circuit board with the LEDs, advantageously distributes the light, scattering it evenly through the designated cutout of the masking print and emitting it through the surface of the laminated pane, rather than laterally into the pane.

[0008] If the cutouts in the cover print or other geometric structures are positioned particularly close to the light elements, such as the LEDs used as light sensors, the PVB film will be illuminated, resulting in an undesirable halo effect, or the light will shine through the cover print instead of the intended cutout, which is also undesirable. These effects can also be unintentionally caused by the curving of the panes. Generally, diffuse light elements in or behind laminated glass emit light in all directions, resulting in what is known as a corona effect.

[0009] It has also been found that the inevitable flow of the composite polymer film(s) used to form the intermediate layer between the two panes of the composite pane can exert mechanical influences on an electronic sensor and / or light element arranged between the panes, leading to a deterioration in its performance and / or reliability or to uneven illumination, for example of a switch. This problem occurs particularly when the actual sensor element, as in LED light sensors, is surrounded by thin, closely spaced conductor structures, which are particularly sensitive. Furthermore, the handling of multilayer stacks, for example for electronic sensor elements under cleanroom conditions, requires millimeter-precise positioning of the individual components, which makes this situation even more difficult.In addition, lamination and bending processes can result in a shift of individual components or structures relative to one another, especially circuit boards with LEDs and a diffuser mounted on them. This further exacerbates the aforementioned unfavorable conditions and leads to undesirable light guide effects.

[0010] The invention is therefore based on the object of specifying an improved composite pane and an improved method for its production, which are suitable for ensuring unrestricted performance and reliability of the embedded electronic sensor element, in particular a light sensor element or an illuminated sensor element, even after passing through the required lamination and / or bending process and for preventing undesired displacements of the electronic components and the occurrence of undesired light effects.

[0011] These and other objects are achieved according to the invention with a composite pane according to claim 1 and with a method according to claim 9. Further advantageous embodiments emerge from the subclaims.

[0012] According to the invention, a composite pane with an integrated sensor element, in particular a touch sensor with lighting or light sensor element, is provided, which comprises at least one outer pane and an inner pane, which are connected to one another via a thermoplastic intermediate layer, wherein the sensor element is arranged at least at one active end of a printed circuit board between the outer pane and the inner pane in a recess of the intermediate layer, wherein the sensor element is designed at this active end as a sensor element package, which comprises electronic SMD components (surface-mounted devices), comprising at least one LED and a diffuser arranged above it in the beam direction of the LED, which are arranged on a printed circuit board and connected to it and furthermore the SMD components, comprising the LED,and the circuit board are enclosed at this active end by a frame-shaped casing. In other words, the components of the sensor element—i.e., the circuit board and the SMD components arranged thereon, in particular the LED, as well as the diffuser arranged above it in the beam direction of the LED—are enclosed by a frame that prevents the components from drifting apart and shifting relative to each other during lamination or a bending process. This leads to a more reliably manufacturable quality of the sensor element embedded in the composite pane, which is particularly advantageous in industrial series production, as significantly fewer rejects are generated. The term "SMD components" is generally known to those skilled in the art and is a common technical term in the field of electronics.

[0013] In a preferred embodiment, the frame-shaped casing is made of a polymer film, particularly preferably of polyvinyl chloride,

[0014] In a further preferred embodiment, the frame-shaped sheath is formed from a polymer film with a thickness in a range of 150 pm to 50 pm, for example with a thickness of 70 pm.

[0015] In a preferred embodiment, the frame-shaped casing of the sensor element package is made of an optically opaque material and arranged in an optically dense manner. This, i.e., the optically opaque and optically dense arrangement of the casing material, i.e., the arrangement of the casing material impermeable to the LED radiation, prevents or reduces lateral emission of the LED light and the occurrence of undesirable lighting effects, such as the halo effect (i.e., the occurrence of light circles, arcs, and / or spots around the sensor element with the LED, which are generated by undesirable refraction and / or reflection of the light), or the corona effect (i.e., the occurrence of ring-shaped halos and circles due to light diffraction), as well as other inhomogeneities in the illumination of the sensor element.According to the invention, lateral "crosstalk" of light into undesired areas, for example outside of an illuminated sensor button, can be significantly reduced or even completely prevented in this way. This advantageously contributes to the illumination, for example of a sensor button, appearing more distinct and clearer to a user. Furthermore, with a light sensor in the sensor element package, the sensor performance can also be improved and overall product quality can be improved. In a preferred embodiment of the composite pane, it is provided that the frame-shaped casing has an emission cutout for the LED, which is arranged substantially overlapping with a corresponding emission cutout in an opaque cover print on the inner and / or outer pane. In other words, the cutouts are preferably arranged substantially congruently to one another.This also ensures that the LED can be fully utilized as an emitter for lighting or as a light sensor, and the cover print also creates a visually appealing appearance by concealing cables and sheathing to the interior and / or exterior.

[0016] In another preferred embodiment, the casing has air outlet devices, preferably radial lateral incisions. Through the air outlet devices, which are designed, for example, and preferably, in the form of radial incisions in the outer edge of the casing, existing air can escape during production, particularly during the lamination process, and undesirable, quality-reducing air pockets can be prevented. The lateral incisions in the casing extend from the outer edge toward the emission cutout, but are expediently not continuous to the emission cutout, so that a closed casing region remains around the emission cutout to stabilize and cover the sensor element and its components.The incisions can be formed, for example, as a straight line or in the shape of acute-angled triangles, with such incision triangles widening towards the outer edge of the casing. These incisions can be created by cutting, but can also be formed, for example, by punching.

[0017] In a preferred embodiment, the circuit board is a flexible circuit board, also known as a flex circuit board. Such circuit boards are made of flexible, bendable polymer films, for example, polyimide films. The films for the circuit board preferably have a thickness of less than 0.5 mm. This achieves particularly good results in terms of flexibility on the one hand and stability on the other. Due to their flexibility and low thickness, flexible circuit boards are particularly suitable for lamination into a composite pane, especially a curved composite pane.

[0018] Since the LEDs, which are preferably used as lighting and / or sensor elements, are surface-mounted SMD components, an SMD circuit board is expediently used.

[0019] The circuit board can be arranged directly on one of the panes, i.e., the inner or outer pane, particularly with the side facing away from the sensor elements, such as LED photodiodes, on the outer surface of the inner pane. It has been shown that the presence of the locally confined circuit board does not have a significant adverse effect on the stability of the finished laminated composite pane. However, the circuit board can also be arranged between two thermoplastic layers, for example, between two layers of the thermoplastic intermediate layer.

[0020] The circuit board has connection surfaces for external electrical contact on the connection end facing away from the active end. These connection surfaces are used to connect the circuit board to external evaluation and control electronics via connection cables, for example to transmit the current pulse generated by a photodiode when light is incident or the switching process triggered by a touch sensor to the evaluation and control electronics. The connection surfaces are preferably contacted using a flat conductor (also called a ribbon conductor or foil conductor). A flat conductor is preferably connected to the connection points of the circuit board, for example using a soldering compound or an electrically conductive adhesive. The flat conductor preferably has a connector (plug or socket) on its end facing away from the circuit board for connecting to other cables of the on-board electronics.

[0021] In a preferred embodiment, the circuit board is arranged entirely within the composite pane and contacted with a flat conductor that extends beyond the side edge of the composite pane. Contacting the circuit board with the flat conductor takes place before the composite pane is manufactured, during which the circuit board is then arranged in the composite stack so that it is completely within the surface of the panes. The advantage is a reduced risk of breakage for the circuit board, which is typically more susceptible to damage than the flat conductor.

[0022] Alternatively, the circuit board can extend from the interior of the composite pane beyond its side edges, with the sensor element package being arranged inside the composite pane and the connection surfaces for the connecting cable outside the composite pane. Contacting the circuit board with the connecting cable can then take place after the composite pane has been manufactured. For example, the composite pane with the integrated sensor element package, in particular the light sensor element package, can be sold to the vehicle manufacturer without a connecting cable, for example, who can then make the contact before installing the composite pane. Of course, the flat conductor can also be connected to the circuit board beforehand, and the composite pane with the integrated sensor element package (preferably a light sensor element package) can be provided together with the connected flat conductor.

[0023] In a preferred embodiment, a plurality of LEDs (light-emitting diodes), for example photodiodes, are preferably arranged on a circuit board in a sensor element package, for example at least four photodiodes, preferably at least six photodiodes. Sensitivity can be increased by a light sensor based on multiple photodiodes. Furthermore, the redundancy can reduce incorrect measurements, and the use of multiple photodiodes also enables the measurement of the radiation direction of the detected light. All LEDs for illumination and / or photodiodes and / or other provided sensors, such as touch sensors, are preferably arranged on the same side of the circuit board in the sensor element package. In an advantageous embodiment, the LEDs are arranged in the form of a matrix with rows and columns.

[0024] The invention further relates to a method for producing a composite pane as described above, comprising the steps:

[0025] A) Applying and connecting at least one SMD component, comprising at least one LED, to and with an active end of a printed circuit board; B) Providing a frame-shaped casing with an emission cutout made of a polymer film;

[0026] C) enclosing the SMD component, in particular the LED, and a diffuser arranged above it in the beam direction of the LED and the circuit board with the frame-shaped casing to form a sensor element package, wherein the LED is arranged at least partially within the emission cutout in the beam direction;

[0027] D) providing an inner pane, an outer pane and at least one composite film;

[0028] E) forming a stacking sequence of the inner pane, the composite film, the sensor element package and the outer pane in this order, wherein the sensor element package is at least partially inserted into a recess of the composite film and

[0029] F) Joining the stacking sequence under the influence of heat, pressure and / or vacuum.

[0030] In a preferred embodiment, in step B), the sheath is cut or punched from a polymer film, for example, a PVC film. These manufacturing steps are particularly simple and cost-effective.

[0031] In another preferred embodiment of the method, in step B), additional air outlet devices are formed, preferably circumferentially, radial lateral incisions on an outer edge region of the casing. These incisions can be created, for example, by cutting or punching. They can be formed in a single punching step for producing the casing from a polymer film. The polymer film remains intact around the intended emission cutout, in particular for light emission, and is therefore not incised, resulting in a frame-shaped, closed cover of the sensor element package in a plan view. Air outlet devices ensure that any air present in and around the sensor element package can escape during the lamination process and that no air pockets are formed.The radially arranged incisions, preferably designed all the way around, also ensure that the sensor element components can be more easily wrapped and enclosed with the film during production. This frame-shaped enclosure prevents, in particular, lateral slippage of the components, such as the LED and a diffuser, from occurring. This significantly simplifies handling during the process, improves overall product quality, and significantly reduces scrap in industrial series production.

[0032] In the production of the composite pane, known processes for lamination in step F) can advantageously be used, for example autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators or combinations thereof.

[0033] The invention further relates to the use of a composite pane with an integrated sensor element, such as a touch switch with illumination or a light sensor, as described above in various embodiments, as a windshield, rear window or side window of a vehicle, preferably a motor vehicle.

[0034] In a further preferred use, it is provided that one or more LEDs serve as illumination for a capacitive touch switch or the LEDs are connected as light sensor elements to an evaluation and control electronics of a vehicle and the switching state of the vehicle lighting, the transmission properties of a window area and / or the intensity of display elements in the vehicle interior are controlled as a function of the ambient light measured by the LEDs (photodiodes).

[0035] The invention is explained in more detail below using exemplary embodiments, with reference to the accompanying figures. They show, in simplified, schematic representations, not to scale:

[0036] Figure 1 shows a composite pane according to the invention in the form of

[0037] Windshield in top view with a sensor element package;

[0038] Figure 2 shows a composite pane with an integrated sensor element without a sheath according to the invention (not according to the invention);

[0039] Figure 3 shows the composite pane according to the invention with the sensor element package from Figure 1 in cross section XX' and Figure 4 shows a plan view of a sensor element with the casing before being enclosed to form the sensor element package (without the printed circuit board shown).

[0040] Figure 1 shows, in an exemplary embodiment, a composite pane 100 according to the invention as a windshield in plan view with a sensor element package 10, which is arranged in the region of the usual edge-side masking area with an opaque cover print 7, often designed as a black print made of enamel, i.e. at the lower end of the motor edge M of the windshield. The positioning of the sensor element package 10 and the circuit board 5 connected thereto can be carried out almost arbitrarily, but particularly preferably in the circumferentially applied masking area with the cover print 7. An edge-side arrangement is also advantageous for the simple implementation of the necessary or desired connections 6 of the sensor element package 10 and the components contained therein to a power supply and / or a control system, in particular of on-board electronics.In the plan view of the outer pane 1, the sensor element package 10 is arranged below the cover print 7, wherein the emission cutout 9a of the casing 8 is arranged congruently with the emission cutout 9b of the cover print 7 and is therefore not visible.

[0041] Figure 2 shows a composite pane 100 as shown in Figure 1 in cross-section XX', but only with an integrated sensor element S, without the casing 8 according to the invention, i.e. in a configuration not according to the invention. In the form shown, the circuit board 5, which carries the LEDs 4 as SMD (surface mounted device) at an active end, is arranged directly on the outer side III of the inner pane 2. The LEDs 4 are covered and surrounded in the beam direction by a PDLC film as a diffuser D. This active end of the circuit board 5 with the sensor element S is arranged in a recess in the intermediate layer 3, for example made of PVB. This allows any height difference to be compensated for by inserting the sensor element S, and glass breakage during production or resulting stresses and distortions in the glass can be prevented.Without the inventive sheathing 8 (see Figure 3), the sensor element S with the LEDs 4 and the diffuser D can slip against each other during lamination to form the composite pane 100 or during a bending process, which can lead to optical and functional degradation. Furthermore, light can be emitted laterally into the PVB interlayer 3, which can produce undesirable light effects, such as corona effects.

[0042] Figure 3 shows, in a preferred embodiment, a composite pane 100 according to the invention with a sensor element package 10 from Figure 1 in cross section X-X', which is arranged between the outer pane 1 and the inner pane 2. The sensor element package 10 is arranged at the active end of the circuit board 5 and enclosed by the frame-shaped casing 8, which can consist, for example, of a polymer film, in particular of a punched or cut polyvinyl chloride film. The casing 8 according to the invention prevents the components, in particular the LED 4 and the diffuser D arranged above it in the beam direction, from slipping during lamination to form the composite pane 100. In other words, the relevant components are enclosed by a frame that prevents them from drifting apart and shifting relative to one another during lamination or during a bending process.This leads to a more reliably manufacturable quality of the sensor element S embedded in the composite pane 100, which is particularly advantageous in industrial series production, since significantly fewer rejects are produced. The casing 8 is preferably made of a material that is opaque to the radiation of the LED and / or optically dense. As a result, lateral radiation of the LED 4 and the occurrence of undesirable light effects, such as the halo effect, corona effect and inhomogeneities in the illumination, for example of a capacitive button with a touch sensor, can be significantly reduced or even completely prevented. Furthermore, the frame-shaped casing 8 has an emission cutout 9a which is preferably arranged essentially congruently, i.e. overlapping in plan view, with an emission cutout 9b in an opaque cover print 7 in the edge-side masking area.This ensures that, by concealing cables and sheathing facing the interior and / or exterior, the LED 4 can fully function as an emitter for the lighting or as a light sensor. Additionally, the cover print 7 creates a visually appealing appearance. The diffuser D ensures uniform light distribution and emission.

[0043] Figure 4 shows a plan view of a sensor element S with multiple LEDs 4 and a diffuser D, for example a PDLC film, with a casing 8 before being enclosed to form the sensor element package 10. The diffuser D is arranged between the LEDs 4 and the casing 8. In this exemplary embodiment, the casing 8 has a round emission cutout 9a within which the majority of the provided LEDs 4 are expediently arranged in a grid-like manner. The emission cutout 9a can alternatively also be designed in other regular or irregular geometric shapes, for example square or hexagonal, and can advantageously be adapted to the respective application. In a preferred variant, the emission cutouts 9a, 9b in the casing 8 and in the cover print 7 are formed in the same shape and area and are introduced and arranged at least substantially congruently in the composite pane 100.In the illustrated embodiment, the casing 8 has notches 11 on its outer edge, which simplify the enclosing of the sensor element S with the LEDs 4, the diffuser D, and the active end of the circuit board 5. These notches can also help to allow air to escape during the lamination process. In the area where the circuit board 5 protrudes from the sensor element package 10, the frame-shaped casing 8 can have a cutout or be wrapped around it with the notches 11.

[0044] List of reference symbols

[0045] 100 composite panes

[0046] 10 sensor element package

[0047] 1 outer pane

[0048] 2 inner pane

[0049] 3 thermoplastic intermediate layer

[0050] 4 LEDs (photodiodes / illuminators)

[0051] 5 Printed circuit board (PCB)

[0052] 6 Connection (connection cable / flat conductor)

[0053] 7 opaque cover print

[0054] 8 Sheathing

[0055] 9 Section (Emission section)

[0056] 9a Emission cutout sheath

[0057] 9b Emission section cover print (7)

[0058] 11 cuts (in sheath)

[0059] S sensor element

[0060] D diffuser

[0061] O Top edge (roof edge)

[0062] U Lower edge (motor edge)

[0063] XX' cross section

[0064] I outside surface of the outer pane 1

[0065] II Interior surface of the outer pane 1

[0066] III outer surface of the inner pane 2

[0067] IV Interior surface of the inner pane 2

Claims

Patent claims 1. Composite pane (100) with an integrated sensor element (S), in particular a touch sensor with lighting or a light sensor element, at least comprising an outer pane (1) and an inner pane (2) which are connected to one another via a thermoplastic intermediate layer (3), characterized in that the sensor element (S) is arranged at least at one active end of a printed circuit board between the outer pane (1) and the inner pane (2) in a recess of the intermediate layer (3), wherein the sensor element (S) is designed at this active end as a sensor element package (10) which comprises electronic SMD components, comprising at least one LED (4), and a diffuser (D) arranged above it in the beam direction of the LED (4), which are arranged on a printed circuit board (5) and connected to it, and the SMD components and the printed circuit board (5) are enclosed at this active end by a frame-shaped casing (8).

2. Composite pane (100) according to claim 1, characterized in that the frame-shaped casing (8) is made of a polymer film, preferably of polyvinyl chloride.

3. Composite pane (100) according to claim 1 or 2, characterized in that the frame-shaped casing (8) is formed from an optically non-transparent material and is arranged in an optically tight manner.

4. Composite pane (100) according to one of claims 1 to 3, characterized in that the frame-shaped casing (8) is formed from a polymer film with a thickness of 150 pm to 50 pm, preferably with a thickness of 70 pm.

5. Composite pane (100) according to one of claims 1 to 4, characterized in that the frame-shaped casing (8) has an emission cutout (9a) for the LED (4), which is arranged substantially overlapping with a corresponding emission cutout (9b) in an opaque cover print (7) on the inner and / or outer pane (1, 2).

6. Composite pane (100) according to one of claims 1 to 5, characterized in that the frame-shaped casing (8) has air outlet devices and / or radial lateral incisions (11).

7. Composite pane (100) according to one of claims 1 to 6, characterized in that the printed circuit board (5) is a flexible printed circuit board.

8. Composite pane (100) according to one of the preceding claims 1 to 7, characterized in that a plurality of LEDs (4) are arranged on a printed circuit board (5) in a sensor element package (10).

9. A method for producing a composite pane (100) according to any one of the preceding claims 1 to 8, comprising the steps: A) applying and connecting at least one SMD component, comprising at least one LED (4), on and to an active end of a printed circuit board (5); B) providing a frame-shaped casing (8) with an emission cutout (9a) made of a polymer film; C) enclosing the SMD component, in particular the LED (4) and a diffuser arranged above it in the beam direction of the LED, and the circuit board (5) at its active end with the frame-shaped casing (8) to form a sensor element package (10), wherein the LED (4) is arranged at least partially within the emission cutout (9a) in the beam direction; D) providing an inner pane (2), an outer pane (1) and at least one composite film; E) forming a stacking sequence of the inner pane (2), the composite film (3), the sensor element package (10) and the outer pane (1) in this order, wherein the sensor element package (10) is at least partially inserted into a recess of the composite film and F) Joining the stacking sequence under the influence of heat, pressure and / or vacuum.

10. The method according to claim 9, characterized in that in step B) the frame-shaped casing (8) is cut or punched from a polymer film, preferably from polyvinyl chloride.

11. The method according to claim 9 or 10, characterized in that in step B) additional air outlet devices and / or, preferably circumferential, radial lateral incisions (11) are formed on an outer edge region of the casing (8).

12. Method according to one of claims 9 to 11, characterized in that the printed circuit board (5) is connected to a control and / or evaluation electronics, in particular an on-board electronics, at a connection end opposite the active end.

13. Use of a composite pane (100) with an integrated sensor element package (10) according to one of claims 1 to 8 as a windshield, rear window or side window of a vehicle, preferably a motor vehicle.

14. Use according to claim 13, wherein one or more LEDs (4) serve as lighting for a capacitive touch switch or the LEDs (4) are connected as light sensor elements to an evaluation and control electronics of a vehicle and the switching state of the vehicle lighting, the transmission properties of a window area and / or the intensity of display elements in the vehicle interior is controlled as a function of the ambient light measured by the LEDs (4).

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