PATENT DOCUMENT

Publication Number: US-10144107-B2
Application Number: US-201615281025-A
Country: US
Kind Code: B2

Title: Ultrasonic polishing systems and methods of polishing brittle components for electronic devices

Abstract:
Ultrasonic polishing systems and methods of polishing brittle components for electronic devices using ultrasonic polishing systems are disclosed. The ultrasonic polishing system may include an ultrasonic driver and a polishing head operatively coupled to the ultrasonic driver. The ultrasonic drive may have a surface shape that corresponds to a non-planar feature formed in the brittle component. The ultrasonic polishing system may also include an abrasive slurry configured to be disposed between the non-planar feature of the brittle component and the polishing head. The ultrasonic driver may be configured to displace the polishing head toward and away from the non-planar feature formed in the brittle component.

Claims:
What is claimed is: 
     
       1. An ultrasonic polishing system for polishing a non-planar feature formed in a brittle component, the system comprising:
 an ultrasonic driver; 
 a polishing head operatively coupled to the ultrasonic driver and having a surface shape that corresponds to a shape of the non-planar feature formed in the brittle component; and 
 an abrasive slurry configured to be disposed between the non-planar feature of the brittle component and the polishing head; wherein 
 the ultrasonic driver is configured to displace the polishing head toward and away from the non-planar feature formed in the brittle component. 
 
     
     
       2. The ultrasonic polishing system of  claim 1 , wherein the abrasive slurry comprises a solid abrasive material suspended in a liquid, the solid abrasive material having a hardness greater than the brittle component. 
     
     
       3. The ultrasonic polishing system of  claim 2 , wherein a gap formed between the polishing head and the non-planar feature of the brittle component is greater than a grain size of the solid abrasive material. 
     
     
       4. The ultrasonic polishing system of  claim 3 , wherein the polishing head is displaced to:
 contact the non-planar feature of the brittle component; and 
 to form the gap between the polishing head and the non-planar feature of the brittle component that is approximately 150% of the grain size of the solid abrasive material. 
 
     
     
       5. The ultrasonic polishing system of  claim 1 , further comprising an actuating gantry coupled to the ultrasonic driver and configured to move the polishing head in at least one of:
 a first direction; and 
 a second direction, perpendicular to the first direction. 
 
     
     
       6. The ultrasonic polishing system of  claim 1 , wherein the surface shape of the polishing head comprises at least one of:
 a substantially non-linear transition portion; 
 a groove; 
 a protrusion; or 
 an aperture. 
 
     
     
       7. The ultrasonic polishing system of  claim 1 , further comprising an insert surrounding the brittle component and configured to substantially secure the brittle component while the ultrasonic driver displaces the polishing head. 
     
     
       8. The ultrasonic polishing system of  claim 1  further comprising a media flow system in fluid communication with the abrasive slurry, the media flow system configured to recirculate the abrasive slurry. 
     
     
       9. A method for polishing a non-planar feature of a brittle component, the method comprising:
 positioning a polishing head adjacent the non-planar feature of the brittle component, the brittle component at least partially submerged in an abrasive slurry disposed within a housing; 
 moving, at an ultrasonic frequency, at least one of the housing or the polishing head in at least one of:
 a first direction; or 
 a second direction, perpendicular to the first direction; and 
 
 in response to moving at least one of the housing of the polishing head, displacing the abrasive slurry to abrade and polish the non-planar feature of the brittle component; wherein 
 the polishing head comprises a surface shape that corresponds to a shape of the non-planar feature of the brittle component. 
 
     
     
       10. The method of  claim 9 , wherein moving the polishing head comprises repeatedly displacing the polishing head toward and away from the non-planar feature of the brittle component. 
     
     
       11. The method of  claim 10 , wherein displacing the polishing head comprises moving the polishing head to:
 contact the non-planar feature of the brittle component; and 
 form a gap between the polishing head and the non-planar feature of the brittle component, the gap equal to approximately 150% of a grain size of a solid abrasive material of the abrasive slurry. 
 
     
     
       12. The method of  claim 9 , wherein moving the housing comprises repeatedly displacing the brittle component toward and away from the polishing head. 
     
     
       13. The method of  claim 9 , wherein displacing the abrasive slurry to abrade and polish the non-planar feature of the brittle component comprises continuously recirculating the abrasive slurry over the non-planar feature. 
     
     
       14. The method of  claim 9 , further comprising securing the brittle component within the housing prior to positioning the polishing head adjacent the non-planar feature of the brittle component. 
     
     
       15. An ultrasonic polishing system comprising:
 a housing for receiving a brittle component comprising a non-planar feature; 
 a polishing head positioned within the housing, the polishing head having a surface shape that corresponds to a shape of the non-planar feature formed in the brittle component; 
 an abrasive slurry positioned within the housing, the abrasive slurry comprising a solid abrasive material suspended in a liquid; and 
 an ultrasonic driver configured to move at least one of the housing or the polishing head at an ultrasonic frequency to polish the non-planar feature of the brittle component using the abrasive slurry. 
 
     
     
       16. The ultrasonic polishing system of  claim 15 , wherein
 the polishing head comprises a projection having a shape that corresponds to a shape of a groove formed in the brittle component. 
 
     
     
       17. The ultrasonic polishing system of  claim 15 , wherein
 the polishing head comprises a recess having a shape that corresponds to a shape of a protrusion formed in the brittle component. 
 
     
     
       18. The ultrasonic polishing system of  claim 15 , wherein
 the polishing head comprises a T-shaped structure having a shape corresponding to a shape of an aperture formed in the brittle component and a portion of the brittle component surrounding the aperture. 
 
     
     
       19. The ultrasonic polishing system of  claim 15 , wherein a gap formed between the polishing head and the non-planar feature of the brittle component is greater than a grain size of the solid abrasive material. 
     
     
       20. The ultrasonic polishing system of  claim 15 , wherein the solid abrasive material has a hardness greater than the brittle component.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a nonprovisional patent application of and claims the benefit of U.S. Provisional Patent Application No. 62/235,337, filed Sep. 30, 2015 and titled “Ultrasonic Polishing Systems and Methods of Polishing Brittle Components for Electronic Devices,” the disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The disclosure relates generally to polishing brittle components and more particularly to systems and methods of polishing brittle components for electronic devices using an ultrasonic polishing system. 
     BACKGROUND 
     Electronic devices continue to become more prevalent in day-to-day activities. For example, smart phones, tablet computers and electronic devices continue to grow in popularity, and provide everyday personal and business functions to its users. These electronic devices may include a display utilized by the user to interact (e.g., through input/output operations) with the electronic devices and/or receive information therefrom. The display is typically protected by a cover glass, which prevents the display from being damaged during use of the electronic device and/or during undesirable shock events (e.g., drops) which the electronic device may experience in day-to-day use. 
     Conventionally, cover glass is made from reinforced or modified glass. To improve durability, the cover glass can be formed from harder ceramic materials. However, due to the hardness of some ceramic materials, surface finishing operations, such as polishing, may be challenging. Polishing may be particularly difficult if the ceramic component includes non-planar surfaces or features. 
     SUMMARY 
     An ultrasonic polishing system for polishing a non-planar feature formed in a brittle component is disclosed. The ultrasonic polishing system comprises an ultrasonic driver and a polishing head operatively coupled to the ultrasonic driver. The ultrasonic drive has a surface shape that corresponds to the non-planar feature formed in the brittle component. The ultrasonic polishing system also comprises an abrasive slurry configured to be disposed between the non-planar feature of the brittle component and the polishing head. The ultrasonic driver is configured to displace the polishing head toward and away from the non-planar feature formed in the brittle component. 
     A method for polishing a non-planar feature of a brittle component is disclosed. The method comprises positioning a polishing head adjacent the non-planar feature of the brittle component. The brittle component at least partially submerged in an abrasive slurry disposed within a housing. The method also comprises moving, at an ultrasonic frequency, at least one of the housing or the polishing head in at least one of a first direction, and a second direction, perpendicular to the first direction. Additionally, in response to moving at least one of the housing and the polishing head, the method also comprises displacing the abrasive slurry to abrade and polish the non-planar feature of the brittle component. The polishing head comprises a surface shape that corresponds to the non-planar feature of the brittle component. 
     An ultrasonic polishing system is disclosed. The ultrasonic polishing system comprises a housing for receiving a brittle component comprising a non-planar feature, and a polishing head positioned within the housing. The polishing head having a surface shape that corresponds to the non-planar feature formed in the brittle component. The ultrasonic polishing system also comprises an abrasive slurry positioned within the housing. The abrasive slurry comprises a solid abrasive material suspended in a liquid. Additionally, the ultrasonic polishing system comprises an ultrasonic driver configured to move at least one of the housing or the polishing head at an ultrasonic frequency to polish the non-planar feature of the brittle component using the abrasive slurry. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements. 
         FIG. 1  shows an ultrasonic polishing system used to polish a non-planar feature of a brittle component, according to embodiments. 
         FIG. 2A  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to embodiments. A polishing head of the ultrasonic polishing system is positioned in a first position. 
         FIG. 2B  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to embodiments. A polishing head of the ultrasonic polishing system is positioned in a second position. 
         FIG. 3  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to additional embodiments. A polishing head of the ultrasonic polishing system is positioned in a third position. 
         FIG. 4  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to additional embodiments. 
         FIG. 5  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to further embodiments. 
         FIG. 6  shows a cross-section view of the ultrasonic polishing system and brittle component taken along line  2 - 2  of  FIG. 1 , according to embodiments. 
         FIG. 7  shows a cross-section view of the ultrasonic polishing system and brittle component taken along line  2 - 2  of  FIG. 1 , according to further embodiments. The ultrasonic polishing system includes a media flow system. 
         FIG. 8  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to further embodiments. The brittle component includes a protrusion. 
         FIG. 9  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to further embodiments. The brittle component includes a groove. 
         FIG. 10  shows a cross-section view of the ultrasonic polishing system and the brittle component taken along line  2 - 2  of  FIG. 1 , according to further embodiments. The brittle component includes an aperture. 
         FIG. 11  shows a flow chart of an example process for polishing a non-planar feature of a brittle component utilized in an electronic device, according to embodiments. 
         FIG. 12  shows an electronic device that utilizes the brittle component as discussed with respect to  FIGS. 1-11 , according to embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     The following disclosure relates generally to polishing brittle components and more particularly to systems and methods of polishing brittle components for electronic devices using an ultrasonic polishing system. 
     Some example embodiments are directed to a cover or component that is formed from a brittle material, such as sapphire, zirconia, or other ceramic material. Prior to being implemented within the electronic devices, the component formed from the brittle material may undergo a polishing process to improve transparency and/or cosmetic appearance. Flat surfaces of the component may be polished to a desired finish without difficulty. However, polishing intricate or complex geometries may be difficult. For example, if the component includes a cavity or recess, conventional polishing techniques and processes may fall short of providing an adequate or desired polish. In particular, portions of the cavity or recess may have an uneven polish due to functional limitations (e.g., movement, flexibility, compliancy, and so on) of polishing heads (e.g., brushes, bristles, pads and so on) used to polish the cavity. 
     Some example embodiments are directed to an ultrasonic polishing system that includes a polishing head positioned within a housing containing an abrasive slurry and a brittle component formed from a brittle material, submerged in the abrasive slurry. The polishing head and/or the housing are coupled to an ultrasonic driver configured to move the polishing head and/or the brittle component to polish a non-planar feature of the brittle component. The ultrasonic driver moves the polishing head and/or the housing to ensure that the entire non-planar feature of the brittle material is evenly and consistently polished. 
     The polishing head is designed to match the geometry or shape of the non-planar feature of the brittle component to ensure consistent polishing of the brittle material. Specifically, the polishing head has an exterior contact surface with a shape that corresponds to the shape of the non-planar feature of the brittle component. The shape of the exterior contact surface of the polishing head can be a negative of the non-planar feature and/or is a corresponding male/female geometry or shape of the non-planar feature. By including an corresponding shape of the non-planar feature, the polishing head of the ultrasonic polishing system may help to ensure all portions of the non-planar feature are exposed to the polishing head and/or the abrasive polishing slurry evenly, which may result in a consistent polish on the brittle component. 
     The abrasive slurry continuously passes over the non-planar feature of the brittle component during the polishing process to polish the non-planar feature. That is, the motion of the polishing head and/or the housing containing the brittle component may ensure that the abrasive slurry continuously moves, passes-over and/or contacts the non-planar feature. The abrasive properties of the slurry, along with the continuous movement of the abrasive slurry result in the non-planar feature of the brittle component being polished to a desired finish. 
     These and other embodiments are discussed below with reference to  FIGS. 1-12 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting. 
       FIG. 1  shows an ultrasonic polishing system. Ultrasonic polishing system  100  (hereafter, “polishing system  100 ”) includes various components for polishing non-planar features of materials and/or components. That is, and as discussed herein in detail, polishing system  100  may include various components configured to polish non-planar features, geometries and/or features formed in materials and/or components, such that the non-planar features, geometries and/or features have an even surface finish or polish throughout. The terms “non-planar feature or geometries” as discussed herein may refer to portions and/or surfaces of a material or component that are not substantially flat, even, planar or the like. Additionally, non-planar feature or geometries may refer to surfaces or portions of a material or component that includes non-linear transitions portions formed within the material or structure.  FIG. 1  depicts a non-planar feature including a cavity formed within a material, where the cavity includes a base portion, sidewall portion and a curved transition portion positioned between the base portion and the sidewall portion. 
     Polishing system  100  includes a housing  102  for receiving a brittle component  104 . In an example embodiment shown in  FIG. 1 , housing  102  of polishing system  100  is substantially fixed and/or does not move when performing the polishing process on the brittle component  104 . In additional example embodiments discussed herein, housing  102  may be configured to move in at least one direction during the polishing process. As shown in  FIG. 1 , housing  102  has an opening  106  for receiving brittle component  104  and distinct components of polishing system  100  discussed herein. Housing  102  may be formed from any suitable rigid material that can withstand the exposure to the ultrasonic operational parameters of polishing system  100 , discussed herein, for polishing brittle component  104 . 
     Brittle component  104  is positioned within housing  102 , and may rest on a bottom, interior surface of housing  102 . In a non-limiting example shown in  FIG. 1 , the weight of brittle component  104 , the polishing process and/or distinct components of polishing system  100  keep brittle component  104  stationary within housing  102  during the polishing process. In other non-limiting examples (see,  FIG. 6 ) additional layers and/or inserts can be positioned within housing  102  and may substantially surround brittle component  104  to prevent brittle component  104  from moving within housing  102  during the polishing process. Brittle component  104  is formed from a variety of materials that have brittle characteristics or properties. In non-limiting examples, brittle component  104  is formed from glass or ceramics, including, for example, zirconia or sapphire. Additionally, and as discussed herein, brittle component  104  can be utilized within an electronic device, and specifically, brittle component  104  can be used to form a housing and/or a cover for an electronic device. 
     As shown in  FIG. 1 , brittle component  104  includes a non-planar feature or geometry  108  (hereafter, “non-planar feature  108 ”) formed on at least one surface. In the non-limiting example, a cavity is formed within brittle component  104 . Non-planar feature  108  of brittle component  104  includes a curved transition portion between a flat or planar base portion and sidewalls of the cavity formed within brittle component  104 . As discussed herein, non-planar feature  108  is polished using polishing system  100 . 
     Polishing system  100  also includes abrasive polishing slurry (see,  FIGS. 2A and 2B ;  210 ) positioned within housing  102 . The abrasive slurry is omitted from  FIG. 1  for clarity purposes, but will now be discussed in detail and shown and discussed herein with respect to  FIGS. 2A and 2B  (e.g., abrasive slurry  210 ). The abrasive slurry substantially surrounds brittle component  104  within housing  102 . That is, brittle component  104  is submerged in abrasive slurry positioned within in housing  102 . During the polishing process, the abrasive slurry may continuously flow over non-planar feature  108  of brittle component  104  to polish non-planar feature  108 . 
     The abrasive slurry may include a solid abrasive material suspended in a liquid. In some cases, the solid abrasive material is made from a deformable or malleable base material and a substantially tough, hard or solid abrasive material encrusted or impregnated within the base material. The solid abrasive material encrusted or impregnated within the base material may provide the abrasive characteristics for the abrasive slurry that are necessary for polishing non-planar feature  108  of brittle component  104  during a polishing process. In non-limiting examples, the abrasive slurry is a diamond encrusted resin-based material or a diamond impregnated elastomer resin material. The specific material or compositional characteristics of the abrasive slurry, such as the composition of the solid abrasive material or the grain size of the solid abrasive material encrusted or impregnated within the base material, are dependent on various aspects of polishing system  100  and/or brittle component  104 . In non-limiting examples, material or compositional characteristics of abrasive slurry are dependent, at least in part, on the type of material forming brittle component  104 , the geometry of non-planar feature  108  to be polished, the desired polish or finish characteristics for non-planar feature  108 , physical and material characteristics for a polishing component of the polishing system  100 , and so on. The solid abrasive material of the abrasive slurry has a hardness that is greater than the hardness of the brittle material forming brittle component  104  in order to abrade and/or polish non-planar feature  108 , as discussed below in detail. 
     Polishing system  100  also includes a polishing head  112  positioned within the housing  102 . During the polishing process discussed herein, polishing head  112  is positioned within housing  102  adjacent non-planar feature  108  of brittle component  104 . In a non-limiting example, and as discussed herein, polishing head  112  is displaced toward and away from non-planar feature  108  formed in brittle component  104 . Specifically, during the polishing process, polishing head  112  is continuously displaced with respect to brittle component  104 , such that the polishing head  112  is alternated between being positioned a predetermined, maximum distance (D MAX ) (see,  FIG. 2A ) and a predetermined, minimum distance (D MIN ) (see,  FIG. 2B ) from non-planar feature  108  of brittle component  104 . As discussed herein, the distances in which polishing head  112  is displaced is dependent on, at least in part, the grain size of the solid abrasive material of the abrasive slurry. Additionally as discussed herein, the displacement of polishing head  112  aids in flowing of the abrasive slurry over non-planar feature  108  to polish the same. 
     Polishing head  112  can be formed from a variety of materials for polishing non-planar feature  108 . The material used to form polishing head  112  is dependent, at least in part, on the material or composition of brittle component  104  undergoing the polishing process discussed herein. Additionally, the material forming polishing head  112  is dependent, at least in part, on the material or composition of the base material and/or the solid abrasive material forming the abrasive slurry. 
     In a non-limiting example, polishing head  112  is formed from a substantially rigid material. The rigid material forming polishing head  112  includes desired material and/or physical characteristics that depend, at least in part, on the composition of brittle component  104 , the composition of the abrasive slurry and/or the operational parameters of the polishing process discussed herein. In non-limiting examples, the rigid material is substantially dense, substantially tough (e.g., strength, ductility and so on), and/or substantially hard. Having the desired material and/or physical characteristics discussed herein ensures polishing head  112  formed from the rigid material can withstand, for example, the frequency of movement required for polishing non-planar feature  108  of brittle component  104 , and/or provide enough durability to polish brittle component  104  that may be formed from a substantially hard material (e.g., sapphire) as well. In non-limiting examples, polishing head  112  is formed from stainless steel, titanium, carbon steel and any other suitable material having similar and/or the desired material and/or physical characteristics discussed herein. 
     In another non-limiting example, polishing head  112  is formed from a substantially compliant material. Similar to the example including the rigid material discussed above, compliant material forming polishing head  112  includes desired material and/or physical characteristics that depend, at least in part, on the composition of brittle component  104 , the composition of the abrasive slurry and/or the operational parameters of the polishing process discussed herein. However, the same properties or characteristics of brittle component  104 , abrasive slurry and/or the operational parameters of the polishing process may influence the desired material and/or physical characteristics of the compliant material differently. In non-limiting examples, the compliant material is substantially elastic, substantially dense, substantially resilient, and/or has substantial compressive strength. With comparison to the rigid material, which may require the polishing head  112  to be substantially hard, polishing head  112  formed from the complaint material may be substantially elastic and/or flexible. The elasticity and/or flexibility of polishing head  112  ensures that the abrasive slurry is pushed against non-planar feature  108  with enough pressure and/or with enough volume during the polishing process discussed herein to polish brittle component  104  to a desired finish. In non-limiting examples, polishing head  112  is formed from rubber, neoprene, silicone, polyurethane, and/or any other elastomer or substantially compliant material having similar and/or the desired material and/or physical characteristics discussed herein. 
     Polishing head  112  of polishing system  100  has an exterior contact surface  118  positioned within housing  102 , adjacent brittle component  104 . Exterior contact surface  118  has a surface shape that corresponds to the shape of non-planar feature  108  of brittle component  104 . As shown in  FIG. 1 , the surface shape of exterior contact surface  118  substantially corresponds (e.g., male-to-female, positive-to-negative) to the shape of non-planar feature  108 . In the non-limiting example where non-planar feature  108  is curved transition portion of the cavity formed in brittle component  104  (e.g., female portion), exterior contact surface  118  of polishing head  112  has a surface shape (e.g., male portion) corresponding to the non-planar feature. Additionally, the surface shape of exterior contact surface  118  of polishing head  112  includes a shape corresponding to other portions of the cavity formed in brittle component  104 , such as for example, a base portion, and a sidewall portion positioned adjacent non-planar feature  108  (e.g., curved transition portion) of brittle component  104 . Polishing head  112 , and specifically exterior contact surface  118 , is dimensionally (e.g., width) smaller than the cavity formed in brittle component  104  including non-planar feature  108 . The smaller dimension or size of polishing head  112  provides enough space or distance between polishing head  112  and brittle component  104  to allow abrasive slurry to pass between polishing head  112  and brittle component  104  during the polishing processes discussed herein. 
     Polishing system  100  also includes ultrasonic driver  120 . Ultrasonic driver  120  is operatively coupled to polishing head  112  in a non-limiting example shown in  FIG. 1 . However, and as discussed herein, ultrasonic driver  120  may be coupled to distinct and/or multiple components of polishing system  100 . Ultrasonic driver  120  is configured as any suitable apparatus or component that is capable of oscillating polishing head  112  at ultrasonic pulses, frequencies, amplitudes and the like, when polishing brittle component  104 . It is understood that ultrasonic driver  120  includes additional components, such as a transducer, a control system and a power system, for example, to move polishing head  112  in polishing system  100 . 
     Polishing system  100  can also include an actuating gantry  122  coupled to ultrasonic driver  120  and/or polishing head  112 . Although only a single shaft or support is shown for gantry  122 , it is understood that gantry  122  is configured as any suitable gantry, stage, or track system configured to move polishing head  112 , and additional components of polishing system  100  discussed herein, in at least one direction. In a non-limiting example, gantry  122  is configured to move polishing head  112  in a first or axial direction (D A ), as indicated in  FIG. 1 . As discussed herein, the distance between polishing head  112  and brittle component  104  is repeatedly varied in an axial direction (D A ) during the polishing process in order to polish non-planar feature  108 . As such, and in the example shown in  FIG. 1 , ultrasonic gantry  122  is configured to move polishing head  112  in the axial direction (D A ). 
     Additionally, gantry  122  is configured to move polishing head  112  in a second or transversal direction (D T ), perpendicular to the axial direction (D A ), as shown in  FIG. 1 . In a non-limiting example, gantry  122  can move polishing head  112  in the transversal direction (D T ) in conjunction with moving polishing head  112  in the axial direction (D A ). In another non-limiting example, and as discussed herein, gantry  122  can move polishing head  112  only in the transversal direction (D T ), so long as other components of polishing system  100  can repeatedly vary the distance between polishing head  112  and brittle component  104  in an axial direction (D A ) during the polishing process. Polishing head  112  is moved in the transversal direction (D T ) by gantry  122  during the polishing process to ensure all portions of non-planar feature  108  of brittle component  104  is polished. 
     The polishing process will now be discussed briefly with respect to  FIGS. 2A, 2B and 3 .  FIGS. 2A and 2B  show polishing system  200 , substantially identical to polishing system  100  depicted in  FIG. 1 . It is understood that similarly numbered and/or named components may function in a substantially similar fashion. Redundant explanation of these components have been omitted for clarity. 
     As shown in  FIG. 2A , the polishing process of non-planar feature  208  of brittle component  204  has begun. In the non-limiting example, polishing head  212  is positioned within housing  202  and above brittle component  204 . Specifically, gantry  222  has moved polishing head  212  in an axial direction (D A ) away from non-planar feature  208 . In the example shown in  FIG. 2A , polishing head  212  is moved in the axial direction (D A ) a predetermined, maximum distance (D MAX ) from brittle component  204 . The predetermined, maximum distance (D MAX ) is dependent, at least in part, on the material and/or compositional properties of abrasive slurry  210 , the material characteristics of brittle component  204  and/or the desired polish and/or finish for non-planar feature  208  of brittle component  204 . In a non-limiting example, predetermined, maximum distance (D MAX ) between polishing head  212  and brittle component  204  is a distance greater than the grain size of the solid abrasive material of abrasive slurry  210 , and specifically is approximately 150% of the grain size of the solid abrasive material. In the non-limiting example, abrasive slurry  210  is a diamond encrusted resin-based material, and the diamonds formed therein have a grain size of approximately 20 microns. As such, the predetermined, maximum distance (D MAX ) between polishing head  212  and brittle component  204  is within a range of approximately 25 microns and 45 microns, and may be approximately 30 microns. Predetermined, maximum distance (D MAX ) is greater than the grain size of the solid abrasive material to ensure abrasive slurry  210  may move freely and/or without restriction between polishing head  212  and non-planar feature  208  when gantry  222  moves polishing head  212  to the predetermined, maximum distance (D MAX ) and ultrasonic driver  220  pulses polishing head  212 . This also results in abrasive slurry  210  flowing over non-planar feature  208  of brittle component  204  to abrade and/or polish non-planar feature  208 , as discussed herein. 
       FIG. 2B  shows polishing system  200  in a subsequent configuration than shown in  FIG. 2A . Specifically, polishing head  212  system  200  shown in  FIG. 2B  is in a subsequent position or a position that supersedes moving polishing head  212  to the predetermined, maximum distance (D MAX ) from brittle component  204 . Gantry  222  has moved polishing head  212  in an axial direction (D A ) toward non-planar feature  208 . In the example shown in  FIG. 2B , polishing head  212  is moved in the axial direction toward brittle component  204  to be positioned a predetermined, minimum distance (D MIN ) from non-planar feature  208 . Similar to the predetermined, maximum distance (D MAX ), the predetermined, minimum distance (D MIN ) is also dependent, at least in part, on the material and/or compositional properties of abrasive slurry  210 , the material characteristics of brittle component  204  and/or the desired polish and/or finish for non-planar feature  208  of brittle component  204 . In a non-limiting example, predetermined, minimum distance (D MIN ) for polishing head  212  is a distance equal to, or slightly less than, the grain size of the solid abrasive material of abrasive slurry  210 . Continuing the example above with respect to the diamond encrusted resin-based material, the predetermined, minimum distance (D MIN ) between polishing head  212  and brittle component  204  is 20 microns, or alternatively within a range of approximately 15 microns and 18 microns. Predetermined, minimum distance (D MIN ) is equal to or less than the grain size of the solid abrasive material forming abrasive slurry  210  to ensure abrasive slurry  210  positioned between polishing head  212  and non-planar feature  208  is pressed into brittle component  204  with an adequate force or pressure to abrade or polish non-planar feature  208 . Additionally, predetermined, minimum distance (D MIN ) is equal to or less than the grain size of the solid abrasive material to ensure at least a portion of abrasive slurry  210  positioned between polishing head  212  and non-planar feature  208  at the predetermined, maximum distance (D MAX ) (see,  FIG. 2A ) is moved over non-planar feature  208  and/or away from polishing head  212 . 
     As discussed herein, the distance between polishing head  212  and non-planar feature  208  of brittle component  204  may continuously and/or repeatedly vary. The distance may vary between the predetermined, minimum distance (D MIN ) and the predetermined, maximum distance (D MAX ) shown in  FIGS. 2A and 2B . In varying the distance between the predetermined, minimum distance (D MIN ) and the predetermined, maximum distance (D MAX ), polishing head  212  may continuously force abrasive slurry  210  into non-planar feature  208  (e.g., the predetermined, minimum distance (D MIN )) and subsequently allow new and/or additional abrasive slurry  210  to freely flow over brittle component  204  (e.g., the predetermined, maximum distance (D MAX )) to polish non-planar feature  208 . That is, the displacement of the polishing head  212  via gantry  222  and the ultrasonic movements of polishing head  212  via ultrasonic driver  220  causes abrasive slurry  210  to continuously move, be displaced and/or circulate within housing  202 . As a result, as polishing head  212  is moved between the predetermined, minimum distance (D MIN ) and the predetermined, maximum distance (D MAX ), new or “fresh” abrasive slurry  210  is positioned between polishing head  212  and brittle component  204 . Additionally, abrasive slurry  210  previously positioned between polishing head  212  and brittle component  204  is displaced away from brittle component  204  within housing  202  to make room for new abrasive slurry  210 . 
     Although shown and discussed herein as utilizing a single polishing head  212  within polishing system  200  to polish brittle component  204 , it is understood that multiple polishing heads  212  may be utilized in the polishing process. That is, polishing head  212  may be interchanged during the polishing process to repeat the polishing process to achieve distinct polishing characteristics on non-planar feature  208  of brittle component  204 . Additionally, materially and/or compositionally distinct abrasive slurries may be used to polish brittle component  204 , and may be interchanged and/or disposed within housing  202  during the polishing process discussed herein. Furthermore, once brittle component  204  undergoes the polishing process discussed herein, brittle component  204  can be removed from housing  202  and may undergo additional processing, including additional polishing using polishing pads or brushes. 
       FIG. 3  shows a distinct positioning of polishing head  312  of polishing system  300  when performing the polishing process on brittle component  304 . As shown in  FIG. 3 , and as discussed herein in comparison to  FIGS. 1-2B , polishing head  312  is moved in a transversal direction (D T ). In the non-limiting example, gantry  322  moves polishing head  312  in both the axial direction (D A ), as discussed herein with respect to  FIGS. 2A and 2B , and the transversal direction (D T ), as briefly discussed herein with respect to  FIG. 1 . Polishing head  312  is moved in the transversal direction (D T ) to ensure all portions of brittle component  304  is polished to a desired finish. In the non-limiting example, polishing head  312  may be moved in both the axial direction (D A ) and transversal direction (D T ) to ensure that abrasive slurry  310  flows over all portions (e.g., side walls, and transition portions) of the cavity formed in brittle component  304 , including non-planar feature  308 . The combination of moving polishing head  312  in the axial direction (D A ) and transversal direction (D T ) ensures non-planar feature  308  of brittle component  304  is also adequately polished. 
       FIG. 3  also shows another non-limiting step in the polishing process for polishing system  300 . Specifically, polishing head  312  of polishing system  300  may directly contact non-planar feature  308  of brittle component  304  during the polishing process. As shown in  FIG. 3 , the predetermined, minimum distance (D MIN ) (see,  FIG. 2B ) between polishing head  312  and brittle component  304  may be negligible and/or zero, such that polishing head  312  contacts non-planar feature  308  directly. Where polishing head  312  contacts non-planar feature  308  of brittle component  304  directly, no amount of abrasive slurry  310  passes between polishing head  312  and brittle component  304 . In the non-limiting example shown in  FIG. 3 , brittle component  304  may be polished when polishing head  312  is moved from the predetermined, minimum distance (D MIN ) to the predetermined, maximum distance (D MAX ), and vice versa. Additionally, non-planar feature  308  of brittle component  304  may be polished by polishing head  312  directly. That is, the ultrasonic movements of polishing head  312  generated by ultrasonic driver  320 , and contacting polishing head  312  directly to brittle component  304  results in non-planar feature  308  being polished by polishing head  312 . Additionally, and as discussed herein with respect to  FIG. 1 , exterior contact surface  318  of polishing head  312  includes a surface shape corresponding to the shape of non-planar feature  308 . As such, in the non-limiting example shown in  FIG. 3 , non-planar feature  308  of brittle component  304  is evenly and consistently contacted by the entirety of exterior contact surface  318  of polishing head  312  when polishing brittle component  304 . 
     An additional, non-limiting example of polishing system  400  is shown in  FIG. 4 . As shown in  FIG. 4 , and with comparison to  FIGS. 1-3 , polishing head  412  is substantially smaller in size than the cavity formed in brittle component  404  including non-planar feature  408 . Although smaller in size, polishing head  412  includes exterior contact surface  418  that has a surface shape that substantially corresponds to the shape of non-planar feature  408 , as similarly discussed herein. As a result, polishing head  412  is capable and/or configured to abrade and/or polish brittle component  404 , and specifically non-planar feature  408 , so long as polishing head  412  and/or housing  402  is moved in both the axial direction and transversal direction; discussed below in detail. 
     In the non-limiting example shown in  FIG. 4 , ultrasonic driver  420  and gantry  422   a  of polishing system  400  is coupled to housing  402 . Additionally, and as shown in  FIG. 4 , ultrasonic driver  420  is not coupled to polishing head  412 . Rather, polishing head  412  is supported and/or only coupled to gantry  422   b . Polishing head  412  can be moved in at least one direction (e.g., axial direction, transversal direction) as discussed herein with respect to  FIGS. 1-3 , or alternatively, polishing head  412  is stationary and/or held rigidly within housing  402  of polishing system  400 . In the non-limiting example, ultrasonic driver  420  coupled to housing  402  is configured pulse or ultrasonically move housing  402  containing brittle component  404  and gantry  422   a  coupled to housing  402  is configured to repeatedly move housing  402 , and ultimately brittle component  404 , as discussed herein. Specifically, gantry  422   a  coupled to housing  402  is configured to move housing  402  and brittle component  404  in an axial direction (D A ) toward and away from (stationary) polishing head  412  to polish non-planar feature  408  of brittle component  404  in a similar manner as discussed herein with respect to  FIGS. 1-2B . Additionally, gantry  422   a  can also be configured to repeatedly move housing  402  and brittle component  404  in a transversal direction (D T ), as discussed herein with respect to  FIGS. 1 and 3 . 
     In another non-limiting example shown in  FIG. 5 , polishing system  500  includes two distinct ultrasonic motion generators  520   a ,  520   b  and two distinct gantries  522   a ,  522   b . As shown in  FIG. 5 , first ultrasonic driver  520   a  and first gantry  522   a  are coupled to polishing head  512 , and second ultrasonic driver  520   b  and second gantry  522   b  are coupled to housing  502 . Ultrasonic motion generators  520   a ,  520   b  can pulse and/or ultrasonically move polishing head  512  and/or housing  502 , and gantries  522   a ,  522   b  can move polishing head  512  and/or housing  502  in any combination of directions (e.g., axial or transversal) to polish brittle component  504 . In non-limiting example, first gantry  522   a  can move polishing head  512  in an axial direction (D A ), or second gantry  522   b  can move housing  502  in the axial direction (D A ). In another non-limiting example, first gantry  522   a  can move polishing head  512  in the axial direction (D A ), and second gantry  522   b  can move housing  502  in the axial direction (D A ), such that both polishing head  512  and housing  502  are capable of moving in the axial direction (D A ). In conjunction with, or separate from, the non-limiting examples above, first gantry  522   a  can also move polishing head  512  in a transversal direction (D T ), and/or second gantry  522   b  can move housing  502  in the transversal direction (D T ) to aid in polishing non-planar feature  508  of brittle component  504 . 
     As shown in  FIG. 6 , polishing system  600  can include additional features and/or components to aid in polishing non-planar feature  608  of brittle component  604 . Ultrasonic driver of polishing system  600  is omitted from  FIG. 6  for clarity. Polishing system  600  includes insert  624  positioned in housing  602 . Insert  624  is positioned within housing  602  and substantially surrounds brittle component  604 . In a non-limiting example, insert  624  is formed between brittle component  604  and housing  602  to secure brittle component  604  within housing  602 , and/or prevent brittle component  604  from moving during the polishing process. By preventing brittle component  604  from moving within housing  602 , insert  624  may aid in polishing non-planar feature  608  of brittle component  604  to a desired finish. 
     Polishing system  600 , as shown in  FIG. 6 , also includes media flow system  626 . Media flow system  626  is positioned within housing  602  adjacent brittle component  604  and/or polishing head  612 . As shown in  FIG. 6 , media flow system  626  is at least partially submerged in, and in fluid communication with, abrasive slurry  610 . Media flow system  626  may aid in the movement and/or continuous recirculation of abrasive slurry  610  within housing  602  during the polishing process. In a non-limiting example, media flow system  626  may be configured as a pump that may continuously intake abrasive slurry  610  disposed within housing  602  and flow the abrasive slurry  610  toward non-planar feature  608  of brittle component  604 . As discussed herein, the flowing of abrasive slurry  610  over non-planar feature  608  of brittle component  604  results in the polishing of non-planar feature  608 . The flowing or moving of abrasive slurry  610  achieved by the displacing and ultrasonic movement of polishing head  612  and/or housing  602 , as discussed herein with respect to  FIGS. 1-2B , may be supplemented by media flow system  626  to improve polishing quality and/or polishing time. 
       FIG. 7  shows another, non-limiting example of media flow system  726  implemented within polishing system  700 . Similar to  FIG. 6 , ultrasonic driver of polishing system  700  is omitted from  FIG. 7  for clarity. As shown in  FIG. 7 , media flow system  726  includes an inlet  728  formed in and/or through a portion of housing  702 , and a corresponding outlet  730  formed in a distinct portion of housing  702 . In the non-limiting example, abrasive slurry  710  is continuously supplied within housing  702  via inlet  728  to substantially surround brittle component  704  during the polishing process. Simultaneously, abrasive slurry  710  already contained within housing  702  is removed via outlet  730 . As a result of implementing media flow system  726  shown in  FIG. 7 , abrasive slurry  710  is continuously supplied to housing  702  via inlet  728  to flow over and/or polish non-planar feature  708  of brittle component  704 , and is subsequently removed from housing  702  via outlet  730  to make room within housing  702  for newly supplied abrasive slurry  710 . This is distinct from the polishing systems discussed herein with respect to  FIGS. 1-6 , which may have a fixed amount of abrasive slurry supplied to the housing and used to polish the brittle component. 
       FIGS. 8-10  show additional, non-limiting examples of a polishing system configured to polish brittle components having various non-planar features. The ultrasonic drivers of the polishing systems shown in  FIGS. 8-10  are omitted for clarity. Additionally, it is understood that similarly numbered and/or named components may function in a substantially similar fashion. Redundant explanation of these components have been omitted for clarity. 
       FIG. 8  shows non-planar feature  808  as a protrusion extending from a portion of brittle component  804 . Polishing head  812  of polishing system  800  includes exterior contact surface  818  having a surface shape that corresponds to the shape of the protrusion forming non-planar feature  808 . In the non-limiting example shown in  FIG. 8 , polishing head  812  includes a recess having a shape corresponding to the shape of the protrusion. 
       FIG. 9  shows non-planar feature  908  as a groove formed partially through brittle component  904 . Polishing head  912  of polishing system  900  therefore includes exterior contact surface  918  having a surface shape that corresponds to the shape of the groove forming non-planar feature  908 . In the non-limiting example shown in  FIG. 9 , polishing head  912  includes a projection having a shape corresponding to the shape of the groove. Polishing head  912  having the corresponding surface shape for non-planar feature  908  can be configured to polish only a portion of brittle component  904 , or alternatively, polishing head  912  can be rotated by gantry  922  to polish all portions of brittle component  904 . These configurations are shown by the phantom lines in  FIG. 9 , which depict either a newly configured polishing head  912  is positioned adjacent brittle component  904  to polish non-planar feature  908 , or alternatively, that polishing head  912  is rotated to be used to polish all portions of brittle component  904 . 
       FIG. 10  shows a unique non-planar feature as an aperture  1032  formed and/or extending through brittle component  1004 . As a result of aperture  1032  being formed through brittle component  1004 , polishing head  1012  of polishing system  1000  includes a T-shaped structure having a shape corresponding to aperture  1032 . Specifically, and as shown in  FIG. 10  and discussed herein with respect to the polishing process, polishing head  1012  includes a T-shaped structure or configuration having a shape corresponding to aperture  1032  and a portion of brittle component  1004  surrounding aperture  1032 . 
       FIG. 11  depicts an example process  1100  for polishing a non-planar feature of a brittle component utilized in an electronic device. This process may be used with one of various embodiments as discussed above with respect to  FIGS. 1-10 . 
     In operation  1102 , a polishing head of a polishing system is positioned adjacent a non-planar feature of a brittle component. Specifically, the brittle component can be positioned within a housing of the polishing system and the polishing head can be positioned within the housing adjacent the non-planar feature formed in the brittle component. The polishing head includes an external contact surface that has a surface shape that corresponds to the shape of the non-planar feature of the brittle material to be polished. 
     The brittle component is positioned within the housing of the polishing system and is at least partially submerged in an abrasive slurry disposed within the housing. Additionally, the brittle component positioned within the housing can also be secured to the housing by positioning an insert within the housing, where the insert substantially surrounds the brittle component and is positioned between the brittle component and the housing. 
     In operation  1104 , the housing and/or the polishing head are moved. The housing and/or polishing head are moved at an ultrasonic frequency. Additionally, the housing and/or the polishing head are moved in a first direction and/or a second direction, perpendicular to the first direction. The first direction can be toward and/or away from the brittle component. The moving of the housing and/or the polishing head can include repeatedly displacing the polishing head and/or the housing toward and away from (e.g., first direction) the non-planar feature of the brittle component. Additionally, displacing the polishing head and/or the housing can include moving the polishing head and/or the housing to allow the polishing head to contact the non-planar feature of the brittle component and forming a gap between the polishing head and the non-planar feature of the brittle component. The gap formed between the polishing head and the non-planar feature of the brittle component can be dependent on characteristics of the abrasive slurry disposed in the housing of the polishing system. In a non-limiting example, the gap can equal approximately 150% of a grain size of a solid abrasive material forming the abrasive slurry. 
     In operation  1106 , the abrasive slurry is displaced within the housing. Specifically, in response to moving the polishing head and/or housing in operation  1104 , the abrasive slurry is displaced in operation  1106  to abrade and/or polish the non-planar feature of the brittle component. The abrasive slurry moves and/or is displaced between the polishing head and the brittle component, and passes over the non-planar feature of the brittle component. The movement of the housing and/or the polishing head aid in moving the abrasive slurry positioned within the housing over the non-planar feature of the brittle component. Additionally, the displacing of the abrasive slurry includes continuously recirculating the abrasive slurry over the non-planar feature. As the abrasive slurry continuously or repeatedly passes over the brittle component, and specifically the non-planar feature, the abrasive slurry abrades and/or polishes the non-planar feature. 
       FIG. 12  shows an isometric view of an electronic device  1200 . As discussed herein, electronic device  1200  may include various components that may utilize the polished, brittle component having the non-planar feature discussed herein with respect to  FIGS. 1-7 . As shown in  FIG. 9 , electronic device  1200  is implemented as a smart telephone. Other embodiments can implement electronic device  1200  differently, for example, as a laptop or desktop computer, a tablet computing device, a gaming device, a display, a digital music player, a wearable computing device or display, a health monitoring device, and so on. 
     Electronic device  1200  includes a housing  1202  at least partially surrounding a display module  1204 , a cover glass  1206  substantially covering display module  1204  and one or more buttons  1208  or input devices. Housing  1202  can form an outer surface or partial outer surface and protective case for the internal components of the electronic device  1200 , and may at least partially surround display module  1204  positioned within an internal cavity formed by housing  1202 . Housing  1202  can be formed of one or more components operably connected together, such as a front piece and a back piece (not shown). Alternatively, housing  1202  can be formed of a single piece operably connected to display module  1204 . Housing  1202  may be formed from any suitable material that may house and/or may protect the internal components of electronic device  1200 , including display module  1204 . In non-limiting examples, housing  1202  may be formed from glass, or sapphire. 
     Display module  1204  may be substantially surrounded by housing  1202  and/or may be positioned within an internal cavity formed by housing  1202 . Display module  1204  can be implemented with any suitable technology, including, but not limited to, a multi-touch sensing touchscreen that uses liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. Display module  1204  may be positioned within an internal cavity of housing  1202  and may be substantially protected on almost all sides by housing  1202 . 
     Cover glass  1206  may be formed integral with and/or may be coupled to housing  1202  to substantially cover and protect display module  1204 . Cover glass  1206  may cover at least a portion of the front surface of electronic device  1200 . When a user interacts with display module  1204  of electronic device  1200 , the user may touch or contact cover glass  1206 . Cover glass  1206  may be formed from any suitable material that be substantially transparent and may protect display module  1204 . In non-limiting examples, cover glass  1206  may be formed from glass or sapphire. 
     Button  1208  can take the form of a home button, which may be a mechanical button, a soft button (e.g., a button that does not physically move but still accepts inputs), an icon or image on a display, and so on. Further, in some embodiments, button  1208  can be integrated as part of cover glass  1206  of the electronic device  1200 . Button  1208 , like housing  1202 , may be formed from any suitable material that may withstand an undesirable drop event that may occur with electronic device  1200 . In non-limiting examples, button  1208  may be formed from glass, or sapphire. 
     Electronic device  1200  may also utilize the polished, brittle components having the non-planar feature to form at least a portion of an external surface of housing  1202 . That is, a variety of exposed and/or external components of electronic device  1200  may include the polished brittle components. In a non-limiting example shown in  FIG. 9 , the polished, brittle components may be utilized to form housing  1202 . In another non-limiting example, the polished, brittle components can form cover glass  1206 . In a further non-limiting example, the polished, brittle components can also form button  1208 . 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20160929
Publication Date: 20181204
Grant Date: 20181204
Priority Date: 20150930
Inventors: KAMIREDDI, SRIKANTH
HOFFMAN, ALEXANDER M.
Assignee: APPLE INC
CPC Classifications: [{"code": "B24B57/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B37/07", "inventive": true, "first": true, "tree": "[]"}, {"code": "B24B37/042", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B19/009", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B19/009", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B57/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B37/042", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B37/07", "inventive": true, "first": true, "tree": "[]"}, {"code": "B24B57/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B37/07", "inventive": true, "first": true, "tree": "[]"}, {"code": "B24B37/042", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 58408907