JP6147154B2 - Manufacturing method of glass substrate of cover glass for electronic device - Google Patents

Description

  The present invention relates to a cover glass for an electronic device including a cover glass for a portable device used as a cover member for a display screen of a portable device (portable electronic device) and a cover glass for a touch sensor used as a cover member for the touch sensor. The present invention relates to a method for manufacturing a glass substrate.

  In a portable device such as a smartphone, a slate PC (Personal Computer), and a PDA (Personal Digital Assistant), a cover glass is disposed outside the display device in order to protect the display device such as a liquid crystal. Also in the touch sensor, a cover glass is disposed to protect the sensor substrate.

  In general, a cover glass is manufactured by separating a glass substrate of an arbitrary shape from a large single glass plate, and further processing such as printing on the separated glass substrate. As a method for separating the glass substrate from the glass base plate, not only machining but also a method using an etching process is known.

  In patent document 1, the glass base plate which formed the resist pattern in the main surface is etched, and the glass substrate of a desired shape is isolate | separated from the glass base plate. Patent Document 1 states that by forming the outer shape by the etching process in this way, the end surface becomes a mirror surface and has extremely high smoothness, and microcracks that are inevitably generated in machining are not generated. It also states that there is an advantage that even a complicated shape difficult to machine can be easily processed by an etching process.

  In Patent Document 2, after a glass substrate is cut into a desired shape by first etching the glass substrate using a resist pattern formed on the main surface of the plate-like glass substrate as a mask, a glass substrate is further obtained. The glass substrate is second etched in an etchant having a flow in the thickness direction. Patent Document 2 states that a pointed portion protruding from the end face can be reduced in this way, and a glass substrate having high mechanical strength can be obtained.

  In Patent Document 3, a material glass block in which a large number of material plate glasses are integrally stacked via a peelable fixing material is provided, and the material glass block is divided to form a divided glass block having a small area. After polishing the end surface of the divided glass block with a rotary polishing machine having a smooth polishing surface, the edge of each divided plate glass is polished by rotating the end surface with a rotating brush provided with a large number of flexible brush materials radially on the outer periphery. Chamfered. Patent Document 3 states that productivity can be improved by polishing a large number of glass plates at the same time.

JP 2009-167086 A JP 2009-227523 A JP 2010-269389 A

  However, in the manufacturing method of Patent Document 1, the end face shape of the glass substrate is not completely flat, and a sharp shape peculiar to etching separation occurs. In the manufacturing method of Patent Document 2, even if the sharpness of the sharp shape of the end face of the glass substrate is reduced, the shape remains in a reduced form.

  Here, it is also possible to mechanically polish the end face of the glass substrate by using a rotating grindstone after etching by the manufacturing method of Patent Document 1. However, mechanical polishing has to be performed one by one (single wafer polishing), which has a problem of low productivity. In addition, it is necessary to input complicated shape data and perform polishing using a precise processing apparatus, which also reduces productivity.

  In addition, as described in Patent Document 3, it is conceivable to stack and polish with a brush in order to increase productivity. However, a glass substrate that has been subjected to outer shape processing by etching treatment has a sharp shape on the end surface, and thus the dimensional accuracy of the outer shape is unstable. Further, the end of the remaining etching resistant layer protrudes from the end surface of the glass substrate. For these reasons, when a plurality of glass substrates are laminated, accurate alignment is difficult, and the glass substrates are laminated in a state of being slightly shifted. When this is brush-polished, the entire surface of the laminate is polished, so that the protruding end face of a glass substrate is overpolished and the retracted end face is underpolished. That is, there is a problem that the degree of polishing differs for each end face, resulting in processing variations.

  Therefore, the present invention provides a method for producing a glass substrate for a cover glass for an electronic device, which can uniformly flatten the end face of each glass substrate without processing variations when a laminated body in which a plurality of glass substrates are laminated is polished. It is intended to provide.

  In order to solve the above problems, a typical structure of a method for producing a glass substrate of a cover glass for an electronic device according to the present invention is obtained from a single glass base plate, and is laterally viewed in a sectional view in the thickness direction. A lamination step of laminating a plurality of glass substrates in the thickness direction in the shape of a cover glass for an electronic device in which convex portions facing the surface are formed on the end surface, and polishing the side surface of the glass substrate laminate obtained in the lamination step A polishing step, and a polishing tool having a polishing base that is elastically deformable and a polishing pad that is provided on a surface of the polishing base and is deformable together with the polishing base. A polishing substrate is brought into contact with an end surface of the glass substrate through a polishing pad, and the end surface is polished while rotating the polishing substrate.

  According to the above configuration, when a laminated body of a plurality of glass substrates is collectively polished, the polishing substrate and the polishing pad are elastically deformed and follow (follow) the shape of the side surface of the laminated body. A polishing action is evenly produced on the convex portions (top portions) of the end surfaces of the steel plates. Therefore, when a laminated body in which a plurality of glass substrates are laminated is polished, the end surfaces of the glass substrates can be uniformly planarized without processing variations. Further, since the polishing base is elastically deformable, the machining allowance by polishing is controlled not by the position of the polishing tool but by the pressure applied to the laminate of the polishing tool. For this reason, a strict positional relationship is not necessary for the distance between the laminate and the rotating shaft of the polishing tool, and control can be facilitated, so that productivity can be improved.

  The polishing base is a balloon member that has flexibility and is deformed into a predetermined cylindrical shape by fluid pressure introduced into the inside, and the polishing tool attaches the polishing pad to the cylindrical side surface of the balloon member. The one worn is preferred.

  In this case, since the balloon member is flexible and has shape retention force due to fluid pressure, the polishing pad attached to the balloon member comes into contact with the end surface of each glass substrate of the laminate at a constant pressure. As a result, the biasing pressure increases as the sharpness of the end face of each glass substrate increases, following the specific sharpness of the end face of each glass substrate, and preferentially uniform from the high sharpness part. Can be polished. In addition, since the amount of polishing (polishing rate) is adjusted by pressure, the end face can be polished following the shape of the side surface of the laminate, and the exact positional relationship between the distance between the glass substrate and the rotating shaft of the polishing tool is It is unnecessary.

  In the laminating step, it is preferable to form a laminated body by laminating a plurality of glass substrates and urging them from both ends in the thickness direction toward the center in the thickness direction. In this case, by urging from both ends in the thickness direction, a laminated body in which a plurality of glass substrates are assembled is formed, and if the urging is released after the polishing process is finished, the laminated body is applied to the plurality of glass substrates. To separate. This eliminates the need for bonding and peeling processes. Therefore, it is possible to easily separate the glass substrate and the laminated glass substrate.

  It is preferable to polish the end face of the glass substrate simultaneously from a plurality of directions using a plurality of polishing tools. Thereby, polishing time can be shortened.

  Polishing is preferably performed using a polishing tool in a state where an etching resistant layer is provided on the surface of the glass substrate. Thereby, since the surface of the glass substrate is protected by the etching resistant layer, it is possible to prevent the surface of the glass substrate from being damaged in the step of polishing the end face.

  After rough polishing using a polishing tool for rough polishing, it is preferable to perform final polishing using a polishing tool for final polishing. Thereby, the surface of the end surface of the glass substrate can be more smoothly polished.

  ADVANTAGE OF THE INVENTION According to this invention, when grind | polishing the laminated body which laminated | stacked several glass substrates, the end surface of each glass substrate can be each uniformly planarized without process variation.

It is a fragmentary sectional view of the glass substrate which carried out etching isolation | separation by etching with respect to a glass base plate from upper direction and the downward direction. It is a figure explaining the process in which a laminated body is formed in the lamination process of a glass substrate. It is a side view explaining a mode that the laminated body of a glass substrate is grind | polished with an abrasive | polishing tool. It is a top view explaining a mode that grinding | polishing of FIG. It is a fragmentary sectional view which shows the process in which the laminated body of a glass substrate is grind | polished. It is a side view explaining a mode that a laminated body is grind | polished simultaneously from several directions using the polishing tool for rough polishing, and the polishing tool for final polishing. It is a top view explaining a mode that grinding | polishing of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a view for explaining a glass substrate 100. The outer periphery of the glass substrate 100 is generally substantially rectangular. The glass substrate 100 is used as a cover glass for an electronic device that protects a display screen of a mobile terminal, for example. The cover glass for an electronic device includes a cover glass for a portable device used as a cover member for a display screen of a portable device (portable electronic device), a cover glass for a touch sensor used as a cover member for a touch sensor, and a housing. Includes an external protective cover glass that is detachably attached.

  FIG.1 (b) is a figure which shows a glass base plate. The glass substrate 100 is separated from the large-sized glass base plate 180 by an etching process. Specifically, an etching resistant layer 102 (resist layer) having a processing pattern 182 (groove) in the shape of the glass substrate 100 is formed on both main surfaces of a large glass base plate 180, and the glass base plate is formed along the processing pattern 182. By melting, the glass substrate 100 in the shape of a cover glass for electronic equipment is separated from the glass base plate 180.

  FIG.1 (c) is a fragmentary sectional view of the glass substrate 100 just after isolate | separating by an etching process, and is AA sectional drawing of Fig.1 (a). The etching resistant layer 102 remains on both the upper and lower main surfaces of the glass substrate 100. On the end surface of the glass substrate 100, a convex portion 104 is formed at a substantially central portion in the thickness direction in a sectional view. This convex part 104 is the part melt | dissolved last, when the glass substrate 100 isolate | separates as a result of etching from both surfaces of the glass base plate 180. FIG. In this embodiment, the sharpness height H of the convex portion 104 is 50 to 200 μm.

  Instead of performing double-sided etching as in the glass substrate 100 of the present embodiment, for example, only one side may be etched from above to separate the glass substrate 100. In this case, the convex part 104 is formed in the vicinity of the lower surface (surface opposite to the etching surface) of the glass substrate 100. Even in that case, the present invention can be applied in exactly the same manner, and the benefits of the invention can be enjoyed.

  FIG. 2 is a diagram for explaining a process of forming the stacked body 110 in the stacking process of the glass substrate 100. First, as shown in FIG. 2A, a plurality of glass substrates 100 are laminated in the thickness direction (for example, 10 to 50 laminated sheets). Thereafter, as shown in FIG. 2B, the laminating means 106 urges the glass substrate 100 laminated in a plurality of layers inward in the laminating direction from both ends in the thickness direction. By this urging, the plurality of laminated glass substrates 100 are fixed and supported, so that the laminated body 110 is formed.

  In the present embodiment, the stacking means 106 includes a shaft portion 112 that can rotate around the center of the stack 110 and a flange portion 114 that is provided at the tip of the shaft 112 and presses against the stack 110. It is configured with. The laminated body 110 can rotate by rotating the shaft portion 112.

  In this manner, a laminated body 110 in which a plurality of glass substrates 100 are gathered is formed by urging from both ends in the thickness direction. Therefore, if the bias is released after the polishing process is finished, the laminate 110 is separated into a plurality of glass substrates 100. That is, the glass substrate 100 can be easily laminated and the laminated glass substrate 100 can be easily separated.

  However, a glass substrate that has been subjected to outer shape processing by etching processing has a sharp shape on the end surface, and thus the dimensional accuracy of the outer shape is unstable. Further, the end of the remaining etching resistant layer protrudes from the end surface of the glass substrate. For these reasons, when a plurality of glass substrates are laminated, accurate alignment is difficult, and the glass substrates are laminated in a slightly shifted state as shown in FIG.

  FIG. 3 is a side view for explaining how the laminated body 110 of the glass substrate 100 is polished by the polishing tool 200. FIG. 4 is a plan view of FIG. As shown in these drawings, the polishing tool 200 includes an elastically deformable polishing base 202 and a polishing pad 204 provided on the surface of the polishing base 202 and deformable together with the polishing base 202.

  In the present embodiment, the polishing tool 200 includes a polishing base 202 and a polishing pad 204. The polishing substrate 202 is a balloon member that has flexibility and is deformed into a predetermined cylindrical shape by a fluid pressure introduced therein. The fluid may be a gas such as air or a liquid such as water. The polishing pad 204 is attached to the cylindrical side surface of the polishing substrate 202 in an exchangeable manner.

  As a material of the polishing base 202, for example, natural rubber, synthetic rubber (for example, IIR) close to natural rubber having a hardness of 20 to 50 degrees or rubber-like resin is used. The thickness of the polishing substrate 202 is uniform throughout, and is about 0.5 to 2 mm (usually about 1 mm). It is preferable to prepare a plurality of types of polishing substrates 202 according to the size and outer peripheral shape of the laminate 110 to be polished.

  The polishing pad 204 is formed of a sheet material having a thickness of about 1 mm made of, for example, a fibrous cloth such as foamed polyurethane, felt, or nonwoven fabric, or a synthetic resin.

  The polishing tool 200 of this embodiment is performed by supplying a polishing liquid between the laminate 110 and the polishing pad 204. As the polishing liquid, a solution in which abrasive grains that are abrasives are dispersed (free abrasive grains) is used. Although it will not specifically limit if it is an abrasive grain used for grinding | polishing of glass substrates, such as an alumina, diamond powder, a cerium oxide, colloidal silica, as an abrasive grain, It is preferable to use colloidal silica as a free abrasive grain.

  Here, as shown in FIG. 6, the polishing tool 200 is supported by the polishing tool fixing portion 115. The polishing tool fixing portion 115 sandwiches the polishing tool 200 between a shaft portion 116 that can rotate about the center of the polishing tool 200 as a central axis, and a flange portion 118 that is provided at the tip of the shaft portion 116 and fixes the polishing tool 200. It is configured to be provided at a position facing vertically. When the shaft portion 116 of the polishing tool fixing portion 115 rotates, the polishing tool 200 rotates. Further, the polishing tool fixing portion 115 is movable in the direction of separating from the surface to be polished, and is biased toward the laminate 110 with a constant pressure.

  By using the polishing tool 200 having the above-described configuration, the polishing base 202 is brought into contact with the end surface of each glass substrate 100 with the same pressure, following the shape of the side surface of the laminate 110, as shown in FIG. Therefore, even if the glass substrates are stacked in a shifted state, the end surfaces of the respective glass substrates can be uniformly flattened without processing variations.

  As shown in FIG. 4A to FIG. 4C, the polishing base body 202 is interposed via the polishing pad 204 with respect to the end surfaces of the plurality of glass substrates 100 forming the side surface of the laminate 110 using the polishing tool 200. The end surface of the glass substrate 100 is polished while the polishing substrate 202 is rotated. At the same time, by slowly rotating the laminate 110 of the glass substrate 100 together with the laminate means 106, the entire circumference of the laminate 110 is polished while moving the surface to be polished.

  The polishing surface is displaced in the direction of separation due to the outer peripheral shape of the laminate 110 that rotates slowly. As described above, the polishing pad 204 is moved forward and backward by the polishing tool fixing portion 115 being biased with a constant pressure. Following this, it comes into contact with the polishing surface with a constant pressure. In addition, the circle drawn with a broken line in FIG. 4 shows the reference position when the polishing tool fixing part 115 is displaced to the outermost side. Further, the position of the shaft portion 116 of the polishing tool fixing portion 115 is not fixed in order to support the polishing tool 200 so as to pressurize the laminated body 110 with a constant pressure. Therefore, a strict positional relationship (control) is not required for the distance between the laminate and the polishing tool 200, and control can be facilitated, so that productivity can be improved.

  Here, the side surface of the laminate 110 that is the polishing surface has irregularities due to the shift of the glass substrate 100. However, since the polishing base body 202 to which the polishing pad 204 is adhered is made of an elastic material, as shown in FIG. 3, it absorbs the displacement of the unevenness and comes into contact with the end face of each glass substrate 100 with a constant pressure.

  FIGS. 5A and 5B are partial cross-sectional views showing a process in which the laminated body 110 of the glass substrate 100 is polished. FIG. 5A illustrates a state at the start of polishing and FIG. 5B illustrates a state at the end of the polishing. It is. As shown in FIG. 5A, the polishing base body 202 and the polishing pad 204 are elastically deformed to follow (follow) the shape of the side surface of the laminate 110. For this reason, a grinding | polishing effect | action arises uniformly in the convex part 104 (top part) of the end surface of each glass substrate 100 in the laminated body 110. FIG. And as shown in FIG.5 (b), the convex part 104 is grind | polished similarly in each glass substrate 100, and the end surface of each glass substrate 100 is similarly planarized, with the shift | offset | difference of each glass substrate 100 as it is.

  Specifically, the sharpness H of the convex portion 104 of each glass substrate 100 before polishing was 50 to 200 μm, but after the polishing, the convex portion 104 of each glass substrate 100 disappeared and the sharpness was increased. H can be halved to 25-100 μm. In addition, when the number of stacked layers is 30, the width of variation between the individual sharpness heights H of the plurality of glass substrates 100 after polishing (difference between the individual having the largest sharpness height H and the individual having the smallest sharpness height H) is The thickness is 10 μm or less, and the processing uniformity for the plurality of glass substrates 100 can be improved. In addition, in the immersion etching method as shown in Patent Document 2, when the same treatment was performed on the laminate of 30 laminated sheets, the sharpness height H was 50 to 200 μm was 40 to 160 μm, The width of variation between individuals having a sharp height H of a plurality of glass substrates 100 (difference between the individual having the largest sharp height H and the individual having the smallest sharp height H) was about 20 μm.

  Thus, according to the present invention, even when there is a slight shift (unevenness) between the glass substrates 100 when the laminated body 110 in which a plurality of glass substrates 100 are stacked is polished, The end surfaces can be evenly flattened without any processing variations.

  In this embodiment, since the laminate 110 is formed and polished with the etching resistant layer 102 on the surface of the glass substrate 100, the surface of the glass substrate 100 is protected by the etching resistant layer 102. . Therefore, it is possible to prevent the surface of the glass substrate 100 from being damaged in the step of polishing the end surface.

  6 and 7, it is also possible to polish the end face of the glass substrate 100 simultaneously from a plurality of directions using a plurality of polishing tools 200. Thereby, polishing time can be shortened.

  As shown in FIG. 6, the polishing tool 200 is used for rough polishing, and a polishing tool 220 for final polishing is prepared. After the rough polishing is performed using the polishing tool 200 for rough polishing, a standby is performed in advance. It is also possible to finish polishing by exchanging with the polishing tool 220 for finishing polishing. Thereby, the surface of the end surface of the glass substrate 100 can be more smoothly polished.

  For example, the polishing tool 200 for rough polishing uses cerium oxide as the free abrasive grains of the abrasive, while the polishing tool 220 for final polishing uses a colloidal silica having a particle diameter finer than that of cerium oxide to polish the polishing process. It is possible to use an abrasive suitable for the above. In this case, the polishing pads of the polishing tools 200 and 220 are made of a material suitable for each polishing material. Further, the internal pressure or biasing force of the polishing base 202 of the polishing tool 220 for final polishing is made lower than the pressure of the polishing base 202 of the polishing tool 200 for rough polishing, and the size, shape, curvature, etc. of the polishing base 202 are other than that. It is also possible to adjust the parameters. In order to switch between such rough polishing and finish polishing tools, a method of replacing the polishing pad 204 with the polishing base 202, a method of replacing the polishing tool 200 with the polishing tool fixing portion 115, and a polishing tool A method of exchanging or switching the entire polishing tool fixing unit 115 including 200 is possible.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the present embodiment, the glass substrate 100 is polished using the polishing tool 200 with the etching resistant layer 102 on the surface of the glass substrate 100, but the glass substrate 100 has no etching resistant layer 102. Also, the laminate 110 can be constituted and polished. In this case, it is preferable to use a spacer so that the main surface is not damaged.

  In this embodiment, loose abrasive grains are used as the abrasive, but a polishing pad containing fixed abrasive grains may be used. If a specific example is given about this fixed abrasive, it is preferable to contain any one or more of alumina, alumina hydrate, silicon carbide, zirconia, titanium oxide, silica, cerium oxide.

  The present invention relates to a cover glass for an electronic device including a cover glass for a portable device used as a cover member for a display screen of a portable device (portable electronic device) and a cover glass for a touch sensor used as a cover member for the touch sensor. It can utilize as a manufacturing method of a glass substrate.

DESCRIPTION OF SYMBOLS 100 ... Glass substrate, 102 ... Etch-resistant layer, 104 ... Convex part, 106 ... Laminating means, 110 ... Laminated body, 112 ... Shaft part, 114 ... Flange part, 115 ... Polishing tool fixing part, 116 ... Shaft part, 118 ... Flange portion, 180 ... glass base plate, 182 ... processing pattern, 200 ... polishing tool (polishing tool for rough polishing), 202 ... polishing substrate, 204 ... polishing pad, 220 ... polishing tool for final polishing

Claims (6)

A plurality of glass substrates in the shape of a cover glass for an electronic device, which are obtained from a single glass base plate and have convex portions formed on the end face in a cross-sectional view in the thickness direction, are laminated in the thickness direction. Lamination process;
A polishing step of polishing a side surface of the laminate of the glass substrates obtained in the lamination step,
In the polishing step, using a polishing tool having an elastically deformable polishing base and a polishing pad provided on the surface of the polishing base and deformable together with the polishing base, a plurality of the side surfaces of the laminate are formed. A method for producing a glass substrate for a cover glass for an electronic device, wherein the polishing substrate is brought into contact with an end surface of the glass substrate via the polishing pad, and the end surface is polished while rotating the polishing substrate. .   The polishing base is a balloon member that has flexibility and is deformed into a predetermined cylindrical shape by fluid pressure introduced into the inside, and the polishing tool has the polishing pad on the cylindrical side surface of the balloon member. The manufacturing method of the glass substrate of the cover glass for electronic devices of Claim 1 characterized by the above-mentioned.   2. The stacking step is characterized in that the stacked body is formed by stacking a plurality of the glass substrates and urging them from both ends in the thickness direction toward the center in the thickness direction. Or the manufacturing method of the glass substrate of the cover glass for electronic devices of 2.   The method for producing a glass substrate of a cover glass for an electronic device according to any one of claims 1 to 3, wherein an end face of the glass substrate is simultaneously polished from a plurality of directions by using a plurality of the polishing tools.   5. The glass substrate for an electronic device cover glass according to claim 1, wherein the glass substrate is polished with the polishing tool in a state having an etching resistant layer on the surface of the glass substrate. Method.   6. The electronic device cover according to claim 1, wherein rough polishing is performed using the polishing tool for rough polishing, and then final polishing is performed using the polishing tool for final polishing. 6. Manufacturing method of glass substrate of glass.

Images