Motor vehicle body part having an electronically controllable electrophoretic graphic surface and method for producing the electrophoretic graphic surface
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- DR ING H C F PORSCHE AG
- Filing Date
- 2026-01-20
- Publication Date
- 2026-07-30
Smart Images
Figure EP2026051280_30072026_PF_FP_ABST
Abstract
Description
[0001] MOTOR VEHICLE BODY PART WITH AN ELECTRONICALLY CONTROLLED ELECTROPHORESE GRAPHIC SURFACE AND METHOD FOR PRODUCING THE ELECTROPHORESE GRAPHIC SURFACE
[0002] The invention relates to an externally visible motor vehicle body part with an electronically controllable electrophoresis graphic surface for the required activation of one or more patterns, and relates to a method for producing such an electrophoresis graphic surface on a motor vehicle body part.
[0003] A vehicle body panel with an electronically controlled electrophoretic graphic surface can be visually adapted to different situations. For example, depending on the outside temperature and sunlight intensity, the graphic surface can be switched between dark and light to absorb or reflect the sun's infrared radiation. The graphic surface can also display different decorative patterns depending on the vehicle's driving mode, such as rally stripes in the sport mode of the vehicle's driving dynamics control system.
[0004] Commercially available prefabricated electrophoretic graphic surfaces are designed as multilayer films, with the layers essentially consisting of a distal transparent counter-electrode layer, a proximal primary electrode layer with wire primary electrodes embedded in a plastic film, and a microcapsule layer between the primary electrode layer and the counter-electrode layer. These electrophoretic graphic surfaces are relatively thick and therefore exhibit undesirably large steps at the edges. The proximal primary electrode layer is particularly problematic in this respect, as it is formed by relatively thick wires and their embedding, resulting in a significant raised area of the primary electrode layer. Manufacturing processes for producing an electrophoretic graphic surface on a motor vehicle interior component are known from CN 118011 703 A and CN 118605063 A, wherein the microcapsule layer is sprayed on.
[0005] Thermoformable electrically conductive inks are known from WO 201905306 A1 , WO 202370699 A1 and WO 201036319 A1.
[0006] In contrast, the object of the invention is to create a motor vehicle body part with an electronically controllable electrophoresis graphic surface and a method for its production, which has a low elevation of the electrophoresis graphic surface.
[0007] This problem is solved according to the invention with a motor vehicle body part having the features of claim 1 and with a method for producing the electrophoresis graphic surface of the motor vehicle body part having the method steps of claim 4.
[0008] The automotive body part according to the invention has an electrophoresis graphic surface on its outer surface, which functionally consists essentially of a proximal primary electrode layer with several primary electrodes lying in a single area, a distal transparent counter-electrode layer, and a microcapsule layer between the primary electrode layer and the counter-electrode layer. Furthermore, an electronic graphic control is provided for controlling the counter-electrode layer and for selectively controlling the primary electrodes. The terms "proximal" and "distal" refer to the already painted body of the body part, with "proximal" being understood as facing towards the body of the body part and "distal" as facing away from the body of the body part. In this context, "surface" does not necessarily mean a flat surface, but rather any curved surface, whether simple or complex.
[0009] The microcapsule layer contains numerous electrophoresis microcapsules arranged in a single area. These microcapsules are filled with electrically charged dye particles, such as negatively charged light-colored particles and positively charged dark-colored particles. The dye particles float in a capsule fluid within a typically spherical capsule shell without an electric field. When an electric field is applied between the primary electrode layer and the counter electrode layer, the electrically charged dye particles move within the capsule shell in a proximal or distal direction according to their own electrical potential. When the electric field is switched off, the dye particles remain in their final positions due to the viscosity of the capsule fluid until an electric field is applied again.
[0010] According to the invention, the primary electrodes are designed in a track-like manner and are each formed from an electrically conductive electrode varnish applied additively. "Track-like" in this context means that the protrusion of the primary electrodes is at most one-tenth of their width. The electrode varnish can, for example, be formed from a so-called electrically conductive ink, which is applied additively, either directly or indirectly, to the painted surface of the body shell using a suitable printing process.
[0011] The electrode resist preferably has a layer thickness of at most in the single-digit or low double-digit micrometer range. This is sufficient from an electrical perspective, as no significant electrical power needs to be transferred through the primary electrodes. Due to the small layer thickness of the primary electrodes, the overall thickness of the electrophoretic graphic surface is also small, and furthermore, the thickness of the entire electrophoretic graphic surface is largely constant across the entire area. The edges of the electrophoretic graphic surface have a relatively low profile, which is desirable both haptically and visually.
[0012] Since the primary electrodes are additively applied, for example by a printing process, their layout can be relatively easily adapted to the patterns to be displayed by the electrophoresis graphic surface. Because the patterns displayed by the electrophoresis graphic surface on a vehicle body part are usually relatively simple and cover a large area, the layout of the primary electrode layer can also generally be kept relatively simple. This also reduces the complexity of the electronic graphic control, which may only need to control a few hundred or a few thousand primary electrodes.
[0013] In principle, the track-like primary electrodes can be applied using an overspray-free coating process to apply the subsequently drying electrode lacquer liquid. This coating process allows for the rapid and efficient production of the track-like primary electrodes. Alternatively, the electrode lacquer can be formed from a dried electrode lacquer liquid applied using a pressure applicator. A pressure applicator enables highly precise application of the track-like primary electrodes.
[0014] Preferably, at least two track-like primary electrodes have a track width of more than 10.0 mm, which allows large-area segments of the electrophoresis graphic surface to be targeted with very few primary electrodes.
[0015] According to the inventive method for producing the electrophoretic graphic surface of the motor vehicle body part with the features of the device claims, the following process steps are provided:
[0016] Application of the primary electrode layer to an unprinted distal paint layer of a body panel by applying the electrode paint liquid in a web-like pattern using the printing or painting applicator,
[0017] After the electrode varnish liquid has dried: application of the microcapsule layer to the primary electrode layer, for example by a printing process or a printing-like application process,
[0018] Applying the transparent counter-electrode layer to the microcapsule layer, for example by a coating process, and
[0019] Applying a transparent protective layer to the counter-electrode layer. The inventive method allows an electrophoretic graphic surface to be applied to a motor vehicle body part, largely or completely eliminating the need for prefabricated films.
[0020] Preferably, the printing or painting applicator is part of a robot with appropriate kinematics that allows for large-area production of the primary electrode layer.
[0021] An embodiment of the invention will be explained in more detail below with reference to the drawings. The drawings show:
[0022] Figure 1 shows a schematic sectional view of a motor vehicle body part with an electronically controllable electrophoresis graphic surface.
[0023] Figure 2 shows an enlarged section II of the motor vehicle body part of Figure 1, and
[0024] Figure 3 shows a top view III of the motor vehicle body part of Figure 1 during the application of the primary electrode layer.
[0025] The figures show a motor vehicle body part 30, in this case, by way of example, a front hood of a motor vehicle. The motor vehicle body part has a distal paint layer 34 on a metal or plastic body 32, which can be, for example, a transparent clear coat. An electronically controllable electrophoretic graphic surface 10 is applied to the motor vehicle body part 30.
[0026] The electrophoresis graphic surface 10 comprises four layers: a proximal primary electrode layer 20 with several primary electrodes 201-209 arranged in a single area; a microcapsule layer 22 applied to the primary electrode layer 20; a transparent counter-electrode layer 24 applied to the microcapsule layer 22; and a distal transparent protective layer 26, which is itself applied directly to the counter-electrode layer 24. The primary electrodes 201-209 of the primary electrode layer 20 are arranged in a web-like pattern and are formed from an electrically conductive electrode varnish 20' that is additively applied. The electrode varnish 20' was initially applied in liquid form as electrode varnish liquid 20" by a printing or coating applicator 130 and subsequently dried and solidified to form the electrode varnish 20'.In this way, a large number of orbital primary electrodes 201-209 are formed, most of which have an orbital width x20 of more than 10 mm. The primary electrodes 201-209 have a constant layer thickness of at most a few micrometers.
[0027] The microcapsule layer 22 consists of a plurality of electrophoretic microcapsules 22' lying in a single plane, wherein the electrophoretic microcapsules 22' are each filled with electrically charged color particles, for example with positively charged black color particles and with negatively charged color particles in white or in the base color of the body part 30. The spherical electrophoretic microcapsules 22 have a constant diameter in the range of 20-100 pm.
[0028] The distal transparent counter-electrode layer 24 consists of a transparent and electrically conductive counter-electrode layer body 24', and can, for example, be applied directly to the microcapsule layer 22 by a suitable coating process.
[0029] The outermost transparent protective layer 26 is applied directly to the counter electrode layer 24 and consists of a transparent and electrically non-conductive protective layer body 26', which was also applied by a suitable painting process.
[0030] An electronic graphics control unit 40 is functionally assigned to the vehicle body part 30. This unit controls the color switching of the electrophoresis microcapsules 22' of the microcapsule layer 22. The electronic graphics control unit 40 has three voltage sources: a neutral reference voltage source 41, a positive voltage source 42, and a negative voltage source 43. The voltage differences between the neutral reference voltage source 41 and the other two voltage sources 42 and 43 are approximately equal and each measure between 5 and 20 V. The total voltage difference between the positive voltage source 42 and the negative voltage source 43 is always less than 60 V, i.e., in the low-voltage range.
[0031] The electronic graphics control 40 further comprises a primary electrode switch 46 for each primary electrode 201-209, each switch being permanently electrically connected to the respective primary electrode 201-209 via an electrical connection 46'. The counter electrode layer 24 is also permanently electrically connected to the neutral voltage source 41 via an electrical connection 41'. To change the graphic pattern displayed by the electrophoresis graphic surface, the primary electrode switches 46 are connected to either the positive voltage source 42 or the negative voltage source 43 according to the pattern, causing the electrophoresis dye particles of the electrophoresis microcapsules 22 to migrate in a proximal or distal direction according to their electrical potential, thus displaying the desired graphic image. The electronic graphics control can then be switched off again until the next change to the graphic pattern.
[0032] Figure 3 shows a printing robot 100, which essentially consists of a robot base 110, a controllable robot arm 120, and a printing or coating applicator 130. The printing or coating applicator 130 has a nozzle 140 from which an electrode coating fluid 20” emerges without overspray, thus producing the path-like primary electrodes 201-209.
[0033] The microcapsule layer 22, the counter electrode layer 24 and the transparent protective layer 26 can also be applied in a similar manner.
Claims
8 Patent claims 1. Motor vehicle body part (30) with an electronically controllable electrophoresis graphic surface (10) comprising: a distal transparent counter-electrode layer (24), a proximal primary electrode layer (20) with several primary electrodes (201 - 209) lying in one area, an electronic graphic control (40) for selective control of the primary electrodes (201 - 209), and a microcapsule layer (22) between the primary electrode layer (20) and the counter electrode layer (24), wherein the microcapsule layer (22) has a plurality of electrophoresis microcapsules (22') lying in a plane, and wherein the electrophoresis microcapsules (22') are each filled with electrically charged color particles, characterized by the fact that the primary electrodes (201 - 209) are formed in a track-like manner and are made of an electrically conductive and additively applied electrode varnish (20').
2. Motor vehicle body part (30) according to claim 1, wherein the electrode lacquer (20') is formed from a dried electrode lacquer liquid (20") applied by a pressure or a paint applicator (130).
3. Motor vehicle body part (30) according to one of the preceding claims, wherein at least two primary electrodes (201 - 209) have a track width (x20) of more than 10 mm.9 4. Method for manufacturing a motor vehicle body part (30) having the features of claims 1 and 2, comprising the process steps: Application of the primary electrode layer (20) to an unprinted distal paint layer (34) of a body body (32) by applying the liquid electrode paint fluid (20") in a web-like manner using the pressure or paint applicator (130), After the electrode varnish liquid has dried: application of the microcapsule layer (22) to the primary electrode layer (20), Application of the counter electrode layer (24) to the microcapsule layer (22), and Applying a transparent protective layer (26) to the counter electrode layer (24).
5. Method for manufacturing a motor vehicle body part (30) according to claim 4, wherein the printing or painting applicator (130) is part of a printing robot (100).