Exemplary arrangements relate to a housing component for a mobile terminal with a transmitting and/or receiving device, such as a cell phone or a tablet computer. Exemplary arrangements relate to a housing component made of carbon fiber reinforced plastic that provides electromagnetic shielding and that includes an antenna window.
For the production of mobile terminals with transmitting and/or receiving devices, such as cell phones or tablet computers, it is useful to manufacture the housing of the mobile terminal from carbon fiber reinforced plastic. The carbon fiber reinforced plastic has strength values similar to those of other types of molded parts made of cast aluminum/magnesium. A particular feature of the carbon fiber reinforced plastic is that it can absorb impacts, as is occasionally the case when a device is dropped from hand height, with the absorbed kinetic energy being dissipated in the carbon fiber composite and not passed on to other components. Another useful aspect of housings made of carbon fiber reinforced plastic is their low weight. Some types of cell phones, known as “smartphones,” may often weigh 200 g or more, which, when carried in an inside pocket of a suit jacket, can lead to undesirable distortion of the suit. The sometimes one-sided weight of the smartphone is also perceived as annoying. With folding smartphones, i.e. smartphones with a foldable display, the weight increases considerably because each molded part reaches about the weight of a single smartphone.
In international patent application WO 2017/202751 A1, which corresponds to U.S. Pat. No. 10,934,415 the disclosure of which is incorporated herein by reference in its entirety, polycarbonate compositions containing fillers, a carboxylic acid and glycerol or diglycerol esters thereof are disclosed, wherein the fillers are carbon fibers. Such a composite material is disclosed for use in constructing a thin wall application such as so-called ultrabooks or smartphones.
As a rule, applications of carbon fiber composites are characterized by their mechanical properties and their weight. A rather fashionable side effect of carbon fiber composites is the visibility of the carbon fiber scrim or fabric.
The use of carbon fiber composites has been found to have a useful side effect. Due to the high electrical conductivity of the carbon fibers, a housing wall for a cell phone, tablet computer or smartphone has a shielding effect like a Faraday cage. The effect is more pronounced the more directions in which the carbon fiber filaments are regularly laid. There are unidirectional carbon fiber composites, often referred to as UD composites. In unidirectional fabrics, the effect as a Faraday cage is less pronounced and the shielding is strongly dependent on the direction of lay in relation to the orientation of the antenna within the mobile terminal. Other influencing factors are the frequency of the electromagnetic radiation and also the propagation of the electromagnetic radiation as a dipole antenna. Even with a bidirectional fabric or a multilayer fabric with different directions of the filaments, the shielding effect as a Faraday cage increases strongly. In fabrics with few filaments, about 1,000 per strand, the shielding effect is so strong that electromagnetic signal transmission and reception through the material are no longer possible. Compared with another plastic composite material, carbon fiber composite material has the advantage that the electromagnetic radiation from the cell phone is strongly shielded. The shielding performance or the attenuation of the electromagnetic radiation is comparable to the attenuation of a housing made of aluminum and/or magnesium.
In order to operate a transmitting and receiving antenna in a mobile terminal, it is known in aluminum and/or magnesium housings to galvanically isolate one edge of the housing from the rest of the housing. The galvanically separated edge is used as an antenna for the transmission and receipt of electromagnetic signals of the mobile terminal. Such galvanic separation of an edge of a mobile terminal can be recognized externally by apparent design strips. In fact, however, the strips are made of plastic or glass to provide the galvanic isolation.
A comparable design of a housing made of carbon reinforced plastic is not possible, however.
It is therefore useful to provide a housing component including a molded part for use as part of a housing of mobile devices that is made of carbon fiber reinforced plastic, which enables operation of a transmitting and receiving antenna within the mobile device. In exemplary arrangements the housing component includes at least one antenna window. In exemplary arrangements an antenna window may comprise a window portion of a different plastic material that does not shield electromagnetic radiation that is in fixed connection by being inserted into the carbon fiber reinforced molded part or that is formed as an opening into which an insert antenna is positioned. Alternative antenna windows may include an electrically insulating connecting portion of the housing component that isolates an antenna from the carbon fiber of the carbon fiber reinforced plastic.
In exemplary arrangements, it is intended, in contrast to known moldings for housings of transmitting mobile terminals, to incorporate an antenna window into the molded housing component. The exemplary molded housing component thus consists of at least two different materials, whereby in an advantageous exemplary arrangement the material of the antenna window may also be a fiber composite material. Fiber reinforced plastics in fact have a pronounced anisotropy with regard to fracture propagation within their microstructure. In order to prevent a mechanical shock wave from building up at the junction between the different materials due to an abrupt change in mechanical properties, such as local modulus of elasticity or shear modulus, in the event of a mechanical impact on the housing of the mobile terminal, for example by dropping, in such a way that a crack is formed at the junction line between the different materials, it can be provided that the antenna window is made of glass fiber or other fiber reinforced plastic. In some arrangements the glass fibers may be laid in the identical direction as the carbon fibers or woven with the same pattern. Although the mechanical properties are different between carbon fiber reinforced plastic and glass or other fiber reinforced plastic, the anisotropy of the local mechanical properties of the different fiber reinforced materials is comparable. A mechanical shock wave propagates more uniformly when passing from one material to the other. If the antenna window formed as an antenna window portion in which an antenna is inserted or embedded, a plastic material which electrically isolates the antenna from the carbon fiber forms the second material of the antenna window.
In order to increase the electromagnetic attenuation of the body material in the area of the carbon fiber reinforced plastic, and at the same time to make the isotropy of the mechanical shock wave propagation more uniform, it can be provided that the carbon fiber reinforced plastic in some arrangements may comprise a multi-axial carbon fabric. On the other hand, in some arrangements the antenna window can be made of glass fiber reinforced plastic to adjust the shock wave propagation.
In some exemplary arrangements in order to increase stability in the region of the junction of the carbon fiber reinforced plastic and the antenna window and to reduce a tendency to break along the junction line in the event of an impact, it may be provided that the junction between the carbon fiber reinforced plastic and the antenna window may include interengaging projections and recesses, for example the body may include a recess therein formed as an undercut, wherein a negative shape of the undercut in the carbon fiber reinforced plastic corresponds to a positive shape projection within the undercut on the antenna window. Further in exemplary arrangements the joint between the carbon fiber reinforced plastic and the antenna window is covered with an overmold layer of plastic on at least one transverse side.
The interengagement of the undercut ensures that the different materials are joined in fixed engagement and interlock tightly. Overmolding a plastic layer that extends over a part of the body portion and a part of the window portion and which can be applied to the housing component in the injection molding process, ensures the positive mold and the negative mold of the undercut are positively connected by engagement with one another and the overmold layer before lateral breakout.
For further stabilization of the connection between the carbon fiber reinforced plastic body portion and the antenna window portion, it can be provided that the connection between the carbon fiber reinforced plastic body and the antenna window is designed as an overlap in which one of the body and the window is in overlying relation with the other. For this purpose in some arrangements, the carbon fiber reinforced plastic body may be reduced to about half its wall thickness by milling. The antenna window can be formed and held in fixed connection with the body by applying a prepreg and pressing under heat or by applying a thermoplastic and glass fiber reinforced plastic to the milled surface.
As an alternative to an antenna window that extends through the entire housing component wall and that is permeable to electromagnetic radiation, an antenna window portion may be incorporated in a first side of a wall of the carbon fiber reinforced body portion that extends to a reduced thickness such as about half the surrounding wall thickness. The first side is configured to serve as an external side of the terminal housing. To utilize the antenna window portion, an antenna can be incorporated in the window portion, which has an electrical connection through the carbon fiber reinforced wall to connect the antenna to electronics located on a second side of the molded body of the housing component, that is configured to be on an internal side of the terminal housing when the terminal is assembled.
In an exemplary arrangement it may be provided that the antenna window portion is embedded in the surface of the first side of the molded body made of carbon fiber reinforced plastic. In this arrangement an antenna such as a coil antenna made of carbon fibers is positioned within the antenna window portion. Carbon fibers have a specific electrical conductivity comparable to metallic electrical conductivity, and optionally the conductivity of carbon fibers is even higher. Carbon fibers of the exemplary antenna may be sheathed with or otherwise surrounded by thermoplastic resin to bond them to the resin and bonding them together during compression under heat. This sheathing results in a shell providing good electrical insulation of the individual carbon fibers of the antenna. If the carbon fibers and the shell are now placed in the embedded antenna window portion like a coil antenna, and if the ends of the carbon fibers are passed through the fabric or scrim of the carbon fibers which reinforce the plastic of the body, the organic carbon antenna can be used like a metallic antenna. The use of an organic carbon fiber antenna in some arrangements has the further advantage that the body component is completely transparent to X-rays. Cell phones, smartphones, tablet computers can thus be better screened during a routine inspection at the airport or in other security areas. For the construction of the molded part of the body including carbon fiber reinforced plastic, it can be provided in some arrangements that the molded body has a multi-layer multi-axial carbon fabric (fabric made of carbon fibers). In an exemplary antenna window portion in which a coil is inserted as a coil antenna made of carbon fibers, the ends of the carbon fibers of the coil antenna may be passed through the multi-axial carbon fabric to the second side. The multilayer carbon fabric shields the electronics present on the second side inside the molded body of the housing component from the transmitting power of the electromagnetic signals output by the antenna.
In a further, alternative arrangement of the molded body part, it can be provided that an insert antenna is arranged in the region of the antenna window. In such an arrangement the antenna is separated by an electrically insulating connecting portion from the carbon fibers of the body. The connecting portion and the antenna is connected to the molded body by overmolding the carbon fiber reinforced plastic. Thus, according to this optional exemplary arrangement, it is provided that the molded body part is equipped with an insert antenna, wherein the insert antenna is on the first side and can transmit and receive electromagnetic signals through the antenna window.
The density of the carbon fibers and the density of the meshes of the fabric have an influence on the shielding effect against electromagnetic radiation in the range from 800 MHz to 4 GHz. Fabrics woven with 1,000 fibers per strand, with 3,000 fibers per strand, and with 12,000 fibers per strand have been found to be useful in exemplary arrangements. Such carbon fiber fabrics are commercially available as 1 K (1,000 fibers/filaments), 3K (3,000 fibers/filaments), and 12 K fabrics (12,000 fibers/filaments). The molded part of the body can be made in exemplary arrangements by compressing a prepreg in a mold or from hot forming a thermoplastic and carbon fiber reinforced plastic or from fibers already coated with a thermoplastic.
In an exemplary arrangement the molded part of the body of the terminal housing component may have a side wall on a first side of the molded body that comprises an antenna window. The window includes an electrically insulating connecting portion of the housing component. Metallic high-performance antenna may be positioned, wherein the material of the connecting portion of the antenna window galvanically separates the metallic high-performance antenna from the carbon fiber of the carbon fiber reinforced plastic body.
Exemplary arrangements are explained in more detail in the following Detailed Description.
In
In
To avoid forming an undercut in the mold that would require a complex mold to demold, an exemplary enclosure 112′ can be injected into the edge of the housing component as an overmold layer 105. The exemplary enclosure 112′ leans against the inner wall of the housing component and forms a enclosure 105′ for a display 111 in the area of the upper wall edge of the side wall 110, as shown in
Thus the exemplary arrangements described herein achieve improved operation, eliminate difficulties encountered in the use of prior devices, systems and methods, and attain the useful results described herein.
In the foregoing description certain terms have been used for brevity, clarity and understanding. However no unnecessary limitations are to be implied therefrom because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover the descriptions and illustrations herein are by way of examples and the new and useful concepts are not limited to the exact features that have been shown and described.
It should be understood that features and/or relationships associated with one exemplary arrangement can be combined with features and/or relationships from another exemplary arrangement. That is various features and/or relationships from various arrangements can be combined into further arrangements. The new and useful scope of the disclosure is not limited only to the exemplary arrangements that have been shown or described herein.
Having described the features, discoveries and principles of the exemplary arrangements, the manner in which they are constructed and operated, and the advantages and useful results attained, the new and useful features, devices, elements, configurations, parts, combinations, systems, equipment, operations, methods, processes and relationships are set forth in the appended claims.
Number | Date | Country | Kind |
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10 2020 118 348.8 | Jul 2020 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2021/056173 | 7/9/2021 | WO |