Patent Publication Number: US-2023142704-A1

Title: Electronic device comprising a pressure sensor

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from Chinese Utility Model number ZL 2020 2 0134930.7, filed on 21 Jan. 2020, the whole contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus for use in the assembly of an electronic device, a touch screen and electronic device comprising such apparatus and a method of assembling an electronic device. 
     In the development of touch screen consumer electronics, micro pressure sensors are becoming increasingly applied to electronic devices such as mobile telephones. In the manufacture of electronic assemblies in this field, components are typically assembled by means of tolerance control. 
     During manufacture, due to processing conditions and cost-constraints, the tolerances on various parts and components can have a significant influence. This is particularly pertinent when dealing with small and thin film pressure sensors, in which a problem of accumulation of tolerances of various components occurs when the pressure sensor is included in the assembly. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention, there is provided an apparatus for use in the assembly of an electronic device. 
     According to a second aspect of the present invention, there is provided a method of assembling an electronic device. 
     With the apparatus as claimed, the pressure sensor is embedded in the inner elastic layer, and the inner elastic layer is embedded in the outer elastic layer. When the pressure sensor is assembled, the elasticity of the elastic layers is used to overcome any assembly tolerances. This therefore solves the problem of a large accumulation of tolerances of various components when assembling pressure sensors, overcomes the accumulation of assembly tolerances between parts, and ensures that the pressure sensors can be assembled correctly in mass production. 
     Additionally, as the elastic modulus and Poisson’s ratio of the two elastic layers are different, it is convenient to adjust the force state of the elastic layers and the pressure sensor so as to optimize the response of the pressure sensor during touch. 
     Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings. The detailed embodiments show the best mode known to the inventor and provide support for the invention as claimed. However, they are only exemplary and should not be used to interpret or limit the scope of the claims. Their purpose is to provide a teaching to those skilled in the art. Components and processes distinguished by ordinal phrases such as “first” and “second” do not necessarily define an order or ranking of any sort. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG.  1    shows an electronic device in the form of a mobile telephone in accordance with the present invention; 
         FIG.  2    shows a structural schematic diagram of an apparatus in accordance with an embodiment of the present invention; 
         FIG.  3    shows a structural schematic diagram of an alternative apparatus in accordance with an alternative embodiment of the present invention; 
         FIG.  4    shows a further structural schematic diagram of a further alternative apparatus in accordance with a further embodiment of the present invention; 
         FIG.  5    shows a still further structural schematic diagram of a still further apparatus in accordance with a still further embodiment of the present invention; 
         FIG.  6    shows a structural schematic diagram of a further alternative apparatus in accordance with a fifth embodiment of the present invention; 
         FIG.  7    shows a structural schematic diagram of a touch screen comprising an apparatus of the present invention; and 
         FIG.  8    shows a method of assembling an electronic device. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     Figure 1 
     Apparatus for use with an electronic device in accordance with the present invention may be incorporated into an electronic device such as a mobile telephone in the manner of  FIG.  1   . 
     In the embodiment of  FIG.  1   , a user  101  is shown utilizing an electronic device  102  in which electronic device  102  is a mobile telephone. 
     In the embodiment, mobile telephone  102  comprises a touch screen  103 . User  101  can therefore utilize mobile telephone  102  in a conventional manner by applying a pressure by means of their finger to operate mobile telephone  102 . 
     In the mobile telephone  102  in accordance with the invention, mobile telephone  102  comprises and apparatus comprising a pressure sensor embedded into an elastic body. The arrangement as will be described herein ensures that, during assembly of mobile telephone  102 , tolerances can be overcome due to the improved elasticity arising from the present invention and arrangement of the pressure sensor in the elastic body. This addresses the issues typically experienced during assembly due to the large accumulation of tolerances when assembly multiple components in one electronic device. Thus, an improved assembly is provided which assists in the mass production of devices of this type. 
     Figure 2 
     As shown in  FIG.  2   , an embodiment of the present invention provides an apparatus  201 , which comprises a pressure sensor  202 , an inner elastic layer  203 , and an outer elastic layer  204 . Pressure sensor  202  is embedded in inner elastic layer  203 . Inner elastic layer  203  is further embedded in outer elastic layer  204 . 
     In the embodiment, inner elastic layer  203  and outer elastic layer  204  have different elastic moduli. The elastic modulus of inner elastic layer  203  is greater than the elastic modulus of the outer elastic layer  204 . 
     Thus, in the example shown, pressure sensor  202  is embedded in the elastic layer  203 , and elastic layer  203  is embedded in elastic layer  204 . When the pressure sensor  202  is assembled, the elasticity of the elastic layers is used to overcome the assembly tolerances which occur in manufacture, as will be described further with respect to  FIGS.  7  and  8   . The structure therefore solves the problem of a large accumulation of tolerances of various components when assembling the pressure sensor and additionally overcomes the accumulation of assembly tolerances between parts. 
     Additionally, elastic layer  203  and elastic layer  204  also have different Poisson’s ratios, which facilitates the adjustment of force properties of the elastic layers and consequently the pressure sensor, thereby optimizing the response performance of the pressure sensor during touch. 
     In an embodiment, pressure sensor  202  is embedded in the middle of inner elastic layer  203  and may be considered as being embedded in the edge of inner elastic layer  203 . Similarly, inner elastic layer  203  can be considered as being embedded in the middle of outer elastic layer  204  or embedded in the edge of outer elastic layer  204 . 
     When the pressure sensor  202  and inner elastic layer  203  are both embedded at the edge, the recognition accuracy of the pressure sensor can be improved. 
     In addition, the size of inner elastic layer  203  can be adaptively adjusted according to the size of pressure sensor  202 . In an embodiment, inner elastic layer  203  is slightly larger than pressure sensor  202 . 
     Figure 3 
     In an alternative embodiment, as shown in  FIG.  3   , an alternative apparatus  301  comprises a pressure sensor  302 , an inner elastic layer  303  into which pressure sensor  302  is embedded and outer elastic layer  304 . In this embodiment, outer elastic layer  304  comprises an elastic layer that has a viscous effect by itself, for example, it may be an elastic layer formed of substantially viscous glue. 
     Thus, in the embodiment of  FIG.  3   , in addition to the aforesaid outer elastic layer  304  having a viscous effect, an adhesive layer  305  is provided on the surface of outer elastic layer  304 . Adhesive layer  305  provides the surface  306  of outer elastic layer  304  with increased adhesion, and thus, during assembly, adhesive layer  305  assists outer elastic layer  304  to adhere to other components. Further, outer elastic layer  304  can also be stretched when the tolerance of the two components is large, thereby overcoming the influence of the tolerance on the assembly. 
     For example, during assembly, outer elastic layer  304  is arranged between two components (as will be described further with respect to  FIG.  7   ), and the tolerance between the two components is larger than the thickness of outer elastic layer  304 . In this example, outer elastic layer  304  is provided with adhesive layer  305  on its surface  306 . Thus, when outer elastic layer  304  is installed with the components, adhesive layer  305  can be utilized to adhere outer elastic layer  304  to those components. In this way, due to the large tolerance between the two components, and given outer elastic layer  304  is positioned between the two components, it presents an expanded state, thereby overcoming the problem of installation tolerances between components. 
     It is appreciated that, while the previous example provides an outer elastic layer having a viscous effect, outer elastic layer  304 , in alternative embodiments, comprises an elastic layer without a viscous effect, for example, such as a rubber material or similar. However, this embodiment may still comprise a substantially similar outer adhesive layer  305 . 
     In this embodiment, either the surface  306  of outer elastic layer  304  is viscous or the surface of outer elastic layer is provided with an adhesive layer  305 , so that the outermost surface of the outer elastic layer has an adhesion effect. Outer elastic layer  304  is therefore utilized to attach between components, and outer elastic layer  304  can therefore be stretched to overcome the tolerance problem between component or part assembly, so that the installation of the sensor will not be affected by the tolerance between the parts. 
     Figure 4 
     In a further embodiment, as shown in  FIG.  4   , an apparatus  401  comprises a pressure sensor  402 , an inner elastic layer  403  into which pressure sensor  402  is embedded and outer elastic layer  404 . In the embodiment, apparatus  401  further comprises an adhesive layer  405 . 
     In this embodiment, a second adhesive layer  406  is provided between inner elastic layer  403  and outer elastic layer  404 . 
     An adhesive layer  407  is also provided between inner elastic layer  403  and pressure sensor  402 . In this way, the connection between inner elastic layer  403  and outer elastic layer  404  and the connection between inner elastic layer  403  and pressure sensor  402  is improved and made stronger such that the apparatus retains its structure. 
     It is appreciated that variations in the embodiments of any of  FIGS.  2  to  4    may also fall within the claimed invention. Thus, any of the apparatus  201 ,  301 ,  401  may comprise any of the features as appropriate from the other embodiments. For example, an embodiment comprising an adhesive layer between the pressure sensor and the inner elastic layer but without an adhesive layer on the outer elastic layer would be possible. In the embodiment of  FIG.  4   , outer elastic layer  404  may also be substantially viscous or otherwise as per apparatus  201 . Other variations may also be anticipated by the invention. 
     Figure 5 
     A further apparatus  501 , in accordance with a further embodiment of the present invention is now shown in respect to  FIG.  5   . Apparatus  501  comprises a pressure sensor  502 , inner elastic layer  503  and outer elastic layer  504 . In  FIG.  5   , apparatus  501  is shown in schematic exploded form with elastic layers  503  and  504  separate to each other. In use, it is appreciated that elastic layers  503  and  504  would be in contact with each other. 
     In the embodiment of  FIG.  5   , a plurality of grooves  505  is provided in an outer elastic layer  504 , and a plurality of protrusions  506  is provided in inner elastic layer  503 . 
     In the embodiment, the number of protrusions  506  and the number of grooves  505  are identical. In addition, the protrusions  506  and grooves  505  comprise mutually corresponding shapes. 
     Thus, inner elastic layer  503  can be embedded into outer elastic later  504  by inserting the plurality of protrusions  506  into the corresponding grooves  505 . In this way, the arrangement between elastic layer  503  and elastic layer  504  results in a connection of increased strength. 
     Figure 6 
     A still further apparatus  601 , in accordance with a further embodiment of the present invention is now shown in respect to  FIG.  6   . Apparatus  601  comprises a pressure sensor  602 , inner elastic layer  603  and outer elastic layer  604 . In  FIG.  6   , apparatus  601  is shown in schematic exploded form with elastic layers  603  and  604  separate to each other in a substantially similar manner to  FIG.  5   . In use, it is appreciated that elastic layers  603  and  604  would be in contact with each other. 
     In the embodiment of  FIG.  6   , a groove  605  is provided in outer elastic layer  604 . In the embodiment, the shape of groove  605  is identical to that of inner elastic layer  603  such that elastic layer  603  is mutually co-operable with groove  605 . 
     In the embodiment, groove  605  is slightly larger than inner elastic layer  603 , such that inner elastic layer  603  can be positioned in groove  605  and fixed in position in groove  605 . In this way, the connection between inner elastic layer  603  and outer elastic layer  604  is made stronger and is retained securely in use. 
     It is appreciated that that the examples shown in  FIGS.  5  and  6    are suitable examples in accordance with the invention. It is appreciated that any other alternative shapes may be utilized. 
     In the embodiments herein described, the shape of inner elastic layer and outer elastic layer is substantially square or rectangular-shaped. In this way, the shape of the apparatus ensures that the apparatus can meet design needs, in particular as the areas in which the pressure sensors may be applied between components are often elongated in nature. In further embodiments, however, the shape of the layers may be any other suitable shape to meet design requirements. 
     Figure 7 
     Any of the apparatus  201 ,  301 ,  401 ,  501  or  601  described in respect of  FIGS.  2  to  6    can be implemented and incorporated into a touch screen as indicated in  FIG.  1   . As shown in  FIG.  7   , touch screen  701  comprises a screen  702  and a screen frame  703  onto which screen  702  fits. 
     Touch screen  701  further comprises an apparatus  704 , which may be substantially similar to any of the aforementioned apparatus  201 ,  301 ,  401 ,  501  or  601  described herein. Thus, apparatus  704  comprises a pressure sensor, an inner elastic layer and an outer elastic layer. 
     Apparatus  704  is arranged between the screen  702  and screen frame  703 . When screen  702  and screen frame  703  are assembled, a gap  705  is present between screen  702  and screen frame  703 . Gap  705  provides a tolerance. 
     When gap  705  between screen  702  and screen frame  703  is relatively large, and consequently considered to have a large tolerance, compression of the apparatus  704  is reduced and may be considered to be in a free or stretched state. Alternatively, when gap  705  between screen  702  and screen frame  703  is relatively small, that is, when the tolerance is small, the apparatus  704  assumes a compressed state. 
     Thus, apparatus  704  reduces the influence of tolerances when a pressure sensor is installed on a touch screen, thereby overcoming the tolerance problem herein while providing an accurate installation of the pressure sensor. Further, as the elastic modulus and Poisson’s ratio between the two elastic layers are different, the force state of the elastic layers and the pressure sensor can be more easily adjusted, thereby enabling optimization of the response of the pressure sensor during touch events. 
     In the touch screen example of  FIG.  7   , because the touch screen contains the apparatus of the present invention, the force sensor can be embedded effectively in an elastic body meaning that it is the elastic body itself which is used during assembly. The elasticity of the apparatus allows the issues with tolerances during assembly to be overcome thereby solving the problem of accumulation of tolerances of each component when assembling multiple micro-sensors in a given electronic device. The arrangement further ensures that the pressure sensor is implemented correctly during mass assembly processes while also facilitating adjustment of the force state of the elastic layers and the pressure sensor, due to the differences in the elastic modulus and Poisson’s ratio of the elastic layers. As noted, the response of the pressure sensor during a touch even can therefore be optimized. 
     Figure 8 
     A schematic flow chart indicating a method of assembling an electronic device, such as mobile telephone  102  and implementation of the aforementioned apparatus into such and electronic device will now be described with respect to  FIG.  8   . 
     At step  801 , a suitable pressure sensor is obtained. In an embodiment, the pressure sensor is a conventional thin film pressure sensor, although it is appreciated that, any suitable pressure sensor may be utilized. 
     The pressure sensor is then embedded into an inner elastic layer having a given elastic modulus at step  802 . At step  803 , an outer elastic layer is provided and the inner elastic layer having the first elastic modulus is embedded into the outer elastic layer having a second elastic modulus. In particular, the elastic modulus of the outer elastic layer is lower than the elastic modulus of the inner elastic layer. Conversely, it can be said that the inner elastic layer has an elastic modulus greater than the outer elastic layer. This step forms the apparatus of the present invention. 
     The apparatus comprising the pressure sensor, inner elastic layer and outer elastic layer are disposed between a first component and a second component of an electronic device at step  804 . This includes the example described with respect to  FIG.  7   , in which the two components are the touch screen and screen frame which receives the touch screen respectively. 
     The process is completed by incorporating the components, such as the screen and screen frame into an electronic device, such as mobile telephone  102  of  FIG.  1   . 
     It is appreciated that, in specific embodiments, additional steps are included to provide additional layers, such as the adhesive layers described herein. For example, an adhesive layer may be provided between the pressure sensor and the inner elastic layer as part of step  802 . Further, an adhesive layer may be provided following step  803  to the outside surface of the outer elastic layer. It is further appreciated that the outside surface of the outer elastic layer may be provided with the adhesive layer prior to step  803  in which the outer elastic layer is embedded.