Patent Publication Number: US-2018037486-A1

Title: Glass housing, electronic device having the same, manufacturing apparatus and method thereof

Description:
RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. § 119 to Chinese Patent Application No. 201610628997.4, filed on Aug. 3, 2016. The entire content of which is incorporated herein in its entirety. 
     FIELD OF THE INVENTION 
     The present disclosure relates to electronic components, and more particularly relates to a glass housing, an electronic device, a manufacturing apparatus and method thereof. 
     BACKGROUND OF THE INVENTION 
     With the popularity of electronic devices such as smart phones and smart watches which are provided with a touch screen, various manufacturers compete to release differentiated products to attract consumers. A highlight design emerging in current market is to design a housing of the electronic device to be a curved surface. The electronic device with the curved surface can better fit the hand of the user, thus improving the comfort of holding and handling. If the housing of the watch is designed to be a curved surface, it can also better fit the wrist of the user, thus improving the comfort of wearing. In addition, a displaying housing with the curved surface can make the displaying content have more stereoscopic effect, the appearance can thereby be improved. The electronic device becomes more popular using glass as a material of the housing due to its better texture. However, the glass housing of the electronic device, especially with the curved surface, is susceptible to cracking due to accidental fall. 
     SUMMARY 
     Therefore, it is necessary to provide a glass housing, a manufacturing apparatus and method thereof, and an electronic device having the glass housing. 
     A glass housing includes an inner surface comprising a first flat portion and a first curved portion extending inward from a periphery of the first flat portion; an outer surface opposite to the inner surface, the outer surface comprising a second flat portion and a second curved portion extending inward from a periphery of the second flat portion; and a circumferential surface interconnecting the outer surface and the inner surface; wherein a distance between the inner surface and the outer surface ranges from 0.2 mm to 1.0 mm, the first and the second curved portions are arcuate surfaces having radii of curvature ranging from 5 mm to 50 mm. 
     An electronic device is provided including the aforementioned glass housing. 
     A manufacturing apparatus is also provided, which includes a chamber; and an upper die and a lower die disposed in the chamber; wherein the upper die comprises an upper flattened portion and an upper bent portion separated from the upper flattened portion, the lower die comprises a lower flattened portion and a lower bent portion separated from the lower flattened portion, the upper flattened portion and the lower flattened portion are configured to clamp a flat portion of a glass housing, the upper bent portion and the lower bent portion have the same arcuate curved surfaces, and the curved surfaces have radii of curvature ranging from 5 mm to 50 mm, the upper bent portion and the lower bent portion are configured to cooperatively extrude a curved portion of the glass housing. 
     A method of manufacturing the glass housing is also provided, which includes the following steps: cutting a glass mother substrate having a thickness of 0.2 mm to 1 mm into a plurality of glass sub-pieces with a predetermined dimension of the glass housing; CNC processing the glass sub-piece to make the glass sub-piece have a required shape of the glass housing; grinding the glass sub-piece to remove surface scratches and micro-cracks; clamping and positioning a middle portion of the glass sub-piece, then extruding and bending a periphery of the glass sub-piece to form an arcuate curved surface, and the curved surface has a radius of curvature ranging from 5 mm to 50 mm; and immersing the glass sub-piece into an alkali molten salt, thus forming a surface compressive stress layer on a surface of the glass sub-piece. 
     By the configuration of the structural parameters, the aforementioned glass housing can disperse the concentrated stress, enhance the integral strength and reduce the risk that cracks emerge easily by a slight collision due to the concentrated stress. 
     The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings: 
         FIG. 1  is a perspective view of a glass housing according to an embodiment; 
         FIG. 2  is a front view of the glass housing of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view take along line A-A of  FIG. 2 ; 
         FIG. 4  is a side view of the glass housing of  FIG. 2 ; 
         FIG. 5  is a perspective view of a glass housing according to another embodiment; 
         FIG. 6  is a front view of an electronic device according to an embodiment; 
         FIG. 7  is a flowchart of a method of manufacturing a glass housing according to an embodiment; 
         FIG. 8  is a schematic diagram showing glass sub-pieces in various stages of the method of  FIG. 7 ; and 
         FIG. 9  is a schematic view of a manufacturing apparatus of the glass housing according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the invention are described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The various embodiments of the invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     Referring to  FIG. 1  to  FIG. 4 , a glass housing  100  according to an embodiment can be applied to electronic devices such as smart phones or the like, and it can serve as a displaying housing or a back cover plate of phones or the like. 
     The glass housing  100  includes an inner surface  101 , an outer surface  102  opposite to the inner surface  101 , and a circumferential surface  103  interconnecting the outer surface  102  and the inner surface  101 . 
     The inner surface  101  includes a first flat portion  111  and a first curved portion  121  extending inward from a periphery of the first flat portion  111 . The first curved portion  121  is an arcuate surface. The first curved portion  121  has a radius of curvature ranging from 1 mm to 50 mm. In one embodiment, the radius of curvature can range from 5 mm to 50 mm. In another embodiment, the radius of curvature can range from 5 mm to 20 mm. In yet another embodiment, the radius of curvature can range from 5 mm to 10 mm. The smaller the radius of curvature, the more curved the arcuate surface, such that the appearance of the formed glass housing  100  will have a more intense 3D stereoscopic effect. 
     In one embodiment, the first flat portion  111  is shaped as a rectangle having two opposite long sides  112 ,  113  and two opposite short sides  114 ,  115 . In the illustrated embodiment, a radius of curvature of the first curved portion  121  connected to the long sides  112 ,  113  is not equal to a radius of curvature of the first curved portion  121  connected to the short sides  114 ,  115 . Specifically, a radius of curvature of the first curved portion  121  connected to the long sides  112 ,  113  is less than a radius of curvature of the first curved portion  121  connected to the short sides  114 ,  115 . 
     In the embodiment shown in  FIG. 1  to  FIG. 4 , a radius of curvature of the first curved portion  121  connected to the long side  112  is equal to a radius of curvature of the first curved portion  121  connected to the long side  113 . A radius of curvature of the first curved portion  121  connected to the short side  114  is equal to a radius of curvature of the first curved portion  121  connected to the short side  115 . 
     The outer surface  102  also includes a second flat portion  112  and a second curved portion  122  extending inward from a periphery of the second flat portion  112 . The second curved portion  122  and the first curved portion  121  are bent towards the same side, i.e. they are bent towards a side where the inner surface  101  is located. The second curved portion  122  is also an arcuate surface. 
     In one embodiment, the second flat portion  112  is aligned with the first flat portion  111 , and the second flat portion  112  and the first flat portion  111  have the same size, such that when the glass housing  100  is placed on the horizontal plane, orthographic projections of the first flat portion  111  and the second flat portion  112  on the horizontal plane are completely coincided. The second curved portion  122  is aligned with the first curved portion  121 , and the second curved portion  122  and the first curved portion  121  have the same size, such that when the glass housing  100  is placed on the horizontal plane, orthographic projections of the first curved portion  121  and the second curved portion  122  on the horizontal plane are completely coincided. 
     More specifically, radii of curvature of the second curved portion  122  and the first curved portion  121  are the same. In the illustrated embodiment, a distance between the inner surface  101  and the outer surface  102 , i.e., a thickness of the glass housing  100  ranges from 0.2 mm to 1.0 mm. In one embodiment, the glass housing  100  has a thickness ranging from 0.5 mm to 0.7 mm. The glass housing  100  has a uniform thickness, such that the stress concentration can be eliminated and the integral strength of the glass housing  100  can be enhanced. 
     Referring to  FIG. 3 , an angle formed by the tangent of the most distal point of an arc where the second curved portion  122  is located and the extension line of the second flat portion  112  is defined as an angle C. The angle C ranges from 0° to 90°. In one embodiment, the angle C ranges from 0° to 45°. An angle C between the first curved portion  121  and the first flat portion  111  also has the same configuration. 
     In addition, a distance between the most distal point of an arc where the first curved portion  121  is located and the second flat portion  112 , i.e., a height of the glass housing  100  ranges from 0.5 mm to 5.0 mm. 
     In some embodiments, an orthographic projection of the glass housing  100  on the horizontal plane is shaped as a rectangle, which has a length of 50 mm to 500 mm, and a width of 30 mm to 300 mm. 
     In some embodiments, at least one of the inner surface  101  and the outer surface  102  is provided with a decorative layer. The decorative layer can color the glass housing  100  to provide a more appealing appearance. The decorative layer can be formed on the inner surface  101  and/or the outer surface  102  by ink printing or adhering. 
     Specifically, when the decorative layer is formed by ink printing, the decorative layer has a thickness of 5 μm to 40 μm. When the decorative layer is formed by adhering a decorative film, the decorative film has a thickness of 10 μm to 125 μm. The decorative film can be formed by screen printing an explosion-proof membrane with a substrate, and it can also be formed by directly screen printing an adhesive without a substrate. 
     During a manufacturing process of the glass housing  100 , at least one of the inner surface  101  and the outer surface  102  can be subjected to a strengthening treatment, such that the inner surface  101  and/or the outer surface  102  is provided with a surface compressive stress layer. In general, during the machining process of the glass, edges of the glass surface will inevitably generate micro-cracks, which can seriously reduce the strength of the glass. Although a size of the micro-crack can be decreased by physical machining processes such as polishing, further chemical strengthening treatment can achieve a better effect. For example, under a certain temperature, the glass can be immersed into a molten salt, the alkali metal ions in the glass and the alkali metal ions in the molten salt are interchanged by diffusion, therefore the surface compressive stress layer having a certain thickness is formed on the glass surface. Instead of an additional layered structure adhering to the glass surface, the surface compressive stress layer is a strengthening layer formed inwardly from the glass surface with a certain thickness. The micro-crack does not tend to extend due to the surface compressive stress layer, thereby enhancing the strength of the glass. 
     In some embodiments, by the strengthening treatment, the obtained surface compressive stress layer has a thickness of 50 μm to 100 μm. The surface compressive stress layer has a compressive stress of 200 MPa to 300 MPa. A central tensional stress between the inner surface  101  and the outer surface  102  is less than or equal to 100 MPa. 
     In some embodiments, the outer surface  102  is further attached with an anti-fingerprint layer. An initial water droplet angle of the anti-finger printer layer is greater than or equal to 110°. 
     By the configuration of the aforementioned structural parameters, the concentrated stress applied to the glass housing  100  can be dispersed, thus an integral strength of the glass housing  100  is enhanced. The risk that cracks emerge easily by a slight collision due to the concentrated stress is reduced. 
     Referring to  FIG. 5 , a glass housing  200  according to another embodiment is similar to the glass housing  100  shown in  FIG. 1  to  FIG. 4 . For example, the inner surface  201  also includes a first flat portion  211  and a first curved portion  221  extending inward from a periphery of the first flat portion  211 . The first curved portion  221  is also an arcuate surface. The difference is that, a radius of curvature of the first curved portion  221  connected to each side of the first flat portion  211  is constant. The outer surface  202  has a configuration similar to the inner surface  201 , and configurations not mentioned herein can be the same as those in the embodiment shown in  FIG. 1  to  FIG. 4 , which will not be described again. 
     Referring to  FIG. 6 , an electronic device  300  according to an embodiment includes the aforementioned glass housing  100 . In the illustrated embodiment, the electronic device  300  is a smart phone. In alternative embodiments, the electronic device  300  can also be a tablet computer or the like. 
     Referring to  FIG. 7  and  FIG. 8 , a method of manufacturing the aforementioned glass housing  100  is further provided, which includes the following steps: 
     In step S 102 , a glass mother substrate having a thickness of 0.2 mm to 1 mm is cut into a plurality of glass sub-pieces  100 A with a predetermined dimension of the glass housing  100 . The size of the glass mother substrate can be determined according to efficiency and process needs. Cutting methods can be laser cutting or mechanical cutting. 
     In step S 104 , the glass sub-piece  100 A is subjected to CNC processing to obtain a glass sub-piece  100 B having a required shape of the glass housing  100 . 
     In step S 106 , the glass sub-piece  100 B is ground to remove surface scratches and micro-cracks. CNC processing may inevitably damage the processing surface of the glass sub-piece  100 B and generate micro-cracks, some larger micro-cracks can be eliminated by grinding, such that they will not extend easily. 
     In step S 108 , a middle portion of the glass sub-piece  100 B is clamped and positioned, and then a periphery of the glass sub-piece  100 B is extruded and bent by a manufacturing apparatus shown in  FIG. 9 . During step S 108 , edges of the upper surface and the lower surface of the glass sub-piece  100 C can form curved portions, while middle portions of the upper surface and the lower surface are still flat, thereby forming flat portions. 
     Specifically, the glass sub-piece  100 B is heated to a temperature of 690±10° C. The glass sub-piece  100 B is subjected to hot bending under a nitrogen atmosphere, the pressing pressure is 0.14±0.05 MPa, the pressing time is 2±0.5 min. At this moment, a glass sub-piece  100 C is substantially formed, which has a flat portion and a curved portion located at a periphery of the flat portion. 
     Referring to  FIG. 9 , a manufacturing apparatus used in step S 108  is provided. The manufacturing apparatus includes a chamber  500 , and an upper die  510  and a lower die  520  located in the chamber  500 . 
     During extruding and bending, it is necessary to heat the glass sub-piece  100 B under a protective gas atmosphere. The chamber  500  can ensure a better heating performance while providing the protective gas atmosphere. For example, the chamber  500  can be filled with nitrogen. The upper die  510  and the lower die  520  can also be made of materials with high temperature resistance, for example, graphite materials or ceramic materials. In one embodiment, the upper die  510  can also be provided with a silicon rubber layer, such that risks that cracks emerge easily due to the extruding can be reduced. 
     The upper die  510  and the lower die  520  can move towards each other for bending and deforming the glass sub-piece  100 B disposed between the upper die  510  and the lower die  520 . Specifically, the upper die  510  includes an upper flattened portion  511  and an upper bent portion  512  separated from the upper flattened portion  511 . The upper flattened portion  511  and the upper bent portion  512  are separately provided, therefore the upper flattened portion  511  and the upper bent portion  512  can be controlled separately and moved independently. Similarly, the lower die  520  includes a lower flattened portion  521  and a lower bent portion  522  separated from the lower flattened portion  521 . Similarly, the lower flattened portion  521  and the lower bent portion  522  are separately provided, therefore the lower flattened portion  521  and the lower bent portion  522  can be controlled separately and moved independently. By separately providing the flattened portions  511 ,  521  and the bent portions  512 ,  522 , the generation of micro-cracks due to the excessive integral stress of the glass is avoided, thereby improving the yield and the strength of glass products. 
     The upper flattened portion  511  and the lower flattened portion  521  are configured to clamp the flat portions  111 ,  112  of the glass housing  100 . The upper bent portion  512  and the lower bent portion  522  have the same curved surfaces, and the curved surfaces have radii of curvature ranging from 1 mm to 50 mm. In one embodiment, the radii of curvature can range from 5 mm to 50 mm. In another embodiment, the radii of curvature can range from 5 mm to 20 mm. In yet another embodiment, the radii of curvature can range from 5 mm to 10 mm. The upper bent portion  512  and the lower bent portion  522  are configured to cooperatively extrude the curved portions  121 ,  122  of the glass housing  100 . 
     When the glass sub-piece  100 B is subjected to extruding and bending, the upper flattened portion  511  and the lower flattened portion  521  can be controlled to move towards each other, such that the upper flattened portion  511  and the lower flattened portion  521  can clamp and position the glass sub-piece  100 B at a portion corresponds to the flat portions  111 ,  112  of the glass housing  100 . After the glass sub-piece  100 B is fixed and positioned, the upper bent portion  512  and the lower bent portion  522  are then moved towards each other, peripheries of the glass sub-piece  100 B are then extruded. The upper bent portion  512  and the lower bent portion  522  have curved surfaces, such that peripheries of the glass sub-piece  100 C are finally formed into the curved portions  121 ,  122  of the glass housing  100 . 
     In some embodiments, the upper bend portion  512  includes a plurality of (e.g. two, three or four) upper bent sub-portions located around the upper flattened portion  511 . The lower bent portion  522  includes a plurality of lower bent sub-portions located around the lower flattened portion  521 . In alternative embodiments, the upper bent portion  512  can be integrally formed and shaped as a ring, which is disposed on the periphery of the upper flat portion  511 . The lower bent portion  522  can also be integrally formed and shaped as a ring, which is disposed on the periphery of the lower flat portion  521 . 
     In the illustrated embodiment, the upper bent portion  512  and/or the lower bent portion  522  are provided with a heating source to heat the periphery of the glass sub-piece  100 B, while the upper flattened portion  511  and the lower flattened portion  521  are not provided with a heating source, because they only serves to clamp and position the glass sub-piece  100 B. The heat can be conducted by conduction or radiation, for example, a corresponding portion of the glass sub-piece  100 B is precisely radiated and heated by the heating source. By such configurations, the defect that the middle portion of the glass sub-piece  100 B is easily deformed due to an integral hot-pressing can be overcome. 
     In alternative embodiments, both the middle portions and the peripheries of the glass sub-piece  100 B can be heated by providing a heat source on the upper die  510  and the lower die  520 , and the integral glass sub-piece  100 B can be heated by precise radiation. 
     Referring to  FIG. 7  again, in step S 110 , a strengthening treatment is performed. The glass sub-piece  100 C is immersed into an alkali molten salt, such that metal ions within a depth range of 50 μm to 100 μm from the surface of the glass sub-piece  100 C can be exchanged with metal ions in the alkali molten salt, thus forming a surface compressive stress layer on a glass sub-piece  100 D. The surface compressive stress layer has a compressive stress of 200 MPa to 300 MPa by the strengthening treatment. 
     In some embodiments, the method further includes polishing the glass sub-piece  100 C, prior to immersing the glass sub-piece  100 C into the alkali molten salt. The polishing can reduce the micro-cracks generated at the edges in step S 102 , thereby enhancing the strength of the final product, making the final product less susceptible to cracking. 
     In some embodiments, the method further includes forming a decorative layer on a surface of the glass sub-piece  100 D after the strengthening treatment. The decorative layer can color the glass housing  100  to provide a more appealing appearance. The decorative layer can also serve to shield the internal components of an electronic device. The decorative layer can be formed on the inner surface  101  and/or the outer surface  102  by ink printing or adhering. 
     Although the respective embodiments have been described one by one, it shall be appreciated that the respective embodiments will not be isolated. Those skilled in the art can apparently appreciate upon reading the disclosure of this application that the respective technical features involved in the respective embodiments can be combined arbitrarily between the respective embodiments as long as they have no collision with each other. Of course, the respective technical features mentioned in the same embodiment can also be combined arbitrarily as long as they have no collision with each other. 
     The foregoing descriptions are merely specific embodiments of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.