WO2012132293A1 - 電子機器用カバーガラスブランクの製造方法および電子機器用カバーガラスの製造方法 - Google Patents

電子機器用カバーガラスブランクの製造方法および電子機器用カバーガラスの製造方法 Download PDF

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Publication number
WO2012132293A1
WO2012132293A1 PCT/JP2012/001840 JP2012001840W WO2012132293A1 WO 2012132293 A1 WO2012132293 A1 WO 2012132293A1 JP 2012001840 W JP2012001840 W JP 2012001840W WO 2012132293 A1 WO2012132293 A1 WO 2012132293A1
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WIPO (PCT)
Prior art keywords
glass
cover glass
blank
glass blank
press
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Application number
PCT/JP2012/001840
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English (en)
French (fr)
Japanese (ja)
Inventor
磯野　英樹
村上　明
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Hoya株式会社
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Publication date
Application filed by Hoya株式会社 filed Critical Hoya株式会社
Priority to CN2012800155919A priority Critical patent/CN103459335A/zh
Publication of WO2012132293A1 publication Critical patent/WO2012132293A1/ja

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
    • C03B11/06—Construction of plunger or mould
    • C03B11/08—Construction of plunger or mould for making solid articles, e.g. lenses
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B7/00—Distributors for the molten glass; Means for taking-off charges of molten glass; Producing the gob, e.g. controlling the gob shape, weight or delivery tact
    • C03B7/10—Cutting-off or severing the glass flow with the aid of knives or scissors or non-contacting cutting means, e.g. a gas jet; Construction of the blades used
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2215/00—Press-moulding glass
    • C03B2215/40—Product characteristics
    • C03B2215/44—Flat, parallel-faced disc or plate products
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2215/00—Press-moulding glass
    • C03B2215/70—Horizontal or inclined press axis

Definitions

  • the present invention relates to a method for manufacturing a cover glass blank for electronic equipment and a method for manufacturing a cover glass for electronic equipment.
  • a cover glass for a mobile device is used mainly for protecting a display screen in a mobile device such as a mobile phone, a PDA (Personal Digital Assistant), a digital still camera, and a video camera.
  • a mobile device such as a mobile phone, a PDA (Personal Digital Assistant), a digital still camera, and a video camera.
  • the cover glass for portable devices as the cover glass is required to be thin and have high mechanical strength. Therefore, in order to satisfy these required characteristics, a thin glass substrate subjected to chemical strengthening has been produced.
  • Patent Document 1 discloses that chemical strengthening is performed on a sheet glass containing lithium ions and sodium ions.
  • a float method, a downdraw method, or the like is employed as a method for producing a plate glass (or glass substrate).
  • a pressing method can be considered as a method for producing a sheet glass (glass blank) suitable for small-quantity, multi-product production.
  • a known press method is a method (vertical direct press method) in which a molten glass lump is supplied onto a lower mold and a molten glass lump (molten glass lump) is press-molded using the upper mold.
  • this method has a problem that the flatness (shape accuracy) of the glass blank to be produced is poor.
  • the reason for this is as follows.
  • the lower mold is heated by the high-temperature molten glass during the period from the placement of the molten glass block on the lower mold supported by the rotary table to the start of press molding. Therefore, heat is easily transmitted to the rotary table that supports the lower mold, and the rotary table is deformed by the heat. As a result, shape accuracy such as plate thickness deviation and flatness of the glass blank is lowered.
  • the viscosity distribution (temperature distribution) inside the molten glass block immediately before press molding is in a wide range. That is, immediately before press molding, the viscosity difference between the lower side and the upper side inside the molten glass lump is relatively large.
  • press molding is performed in this state, an increase in thickness deviation of the glass blank and a decrease in flatness are caused.
  • the increase in the thickness deviation and the decrease in flatness of the glass blank are due to the time difference between the placement of the molten glass lump on the lower mold and the start of press molding. Can not be suppressed.
  • a solid lubricant such as BN (boron nitride), for example, is applied to the lower mold in order to prevent the molten glass lump from sticking to the lower mold and being unable to be removed.
  • BN boron nitride
  • the transparency deteriorates if such a solid lubricant remains attached to the glass blank.
  • the glass blank produced by the vertical direct press method requires a main surface processing step in a subsequent step in order to improve the flatness and peel off the solid lubricant. For this reason, the conventional press molding method is not suitable for manufacturing a cover glass blank for electronic equipment.
  • An object of the present invention is to provide a method for manufacturing a cover glass blank for electronic equipment suitable for small-quantity, multi-product production and a method for manufacturing a cover glass for electronic equipment.
  • the present inventors conducted extensive research, and as a result, the inventors devised a new press molding method. That is, in the method for manufacturing a glass blank of the present embodiment, a pair of molds (press molds) in which a molten glass lump that is falling is arranged to face each other in a direction (horizontal direction) orthogonal to the dropping direction of the molten glass lump.
  • the horizontal direct press method is used. In this horizontal direct press method, the molten glass lump is not temporarily brought into contact with or held by a member having a temperature lower than that of the molten glass lump until being pressed. This is different from the conventional vertical direct press method.
  • the viscosity distribution inside the molten glass lump becomes very wide at the time of press molding, whereas in the horizontal direct press of this embodiment, the molten glass The viscosity distribution of the mass is kept uniform.
  • the horizontal direct press method makes it extremely easy to stretch the molten glass lump to be pressed uniformly and thinly. Therefore, as a result, compared with the case where the glass blank is manufactured using the vertical direct press method, the decrease in flatness is drastically suppressed when the glass blank is manufactured using the horizontal direct press method. It is very easy.
  • the maximum value of the temperature difference (absolute value) between the pair of molds for realizing the flatness required for the cover glass for electronic equipment can be found. Therefore, by controlling the temperature difference between the pair of molds to be equal to or less than the maximum value, the flatness required for the cover glass for electronic devices can be realized.
  • the present invention is a method for manufacturing a cover glass blank for an electronic device that includes a molding step of press-molding a lump of molten glass using a pair of molds. Based on the correlation between the temperature difference between the opposed positions of the pair of molds and the flatness of the glass blank obtained after press molding, the pair of the above can realize the flatness required for the cover glass for electronic devices.
  • a cover for electronic equipment wherein a temperature difference between molds is obtained and press molding is performed while controlling the temperature of the pair of molds so that the temperature of the pair of molds is within the obtained temperature difference. It is a manufacturing method of a glass blank.
  • the temperature of the portion of the pair of molds that contacts the molten glass is the same temperature between the pair of molds. It is characterized by pressing.
  • the temperature of the pair of molds until the lump comes in contact with the mold and leaves is set to a temperature lower than the glass transition point (Tg) of the molten glass. It is characterized by that.
  • press molding is performed so that the thickness of the glass blank obtained by the press molding step is the same as that required for the cover glass for electronic equipment. It is characterized by performing.
  • the manufacturing method of the cover glass blank for an electronic device preferably includes a cutting step of cutting the molten glass and dropping the lump toward the pair of molds. In the cutting step, a cut mark of the molten glass is formed. The molten glass is cut so as to be positioned at the periphery of the glass blank.
  • the method for producing the cover glass blank for an electronic device preferably includes a cutting step of cutting the molten glass and dropping the lump toward the pair of molds.
  • a cut mark of the molten glass is provided in the press molding step. Is characterized in that the molten glass is pressed at a timing of protruding from the pair of molds.
  • the manufacturing method of the cover glass for electronic devices of this invention is the state which left the distortion which has arisen in the glass blank manufactured by the manufacturing method of the said cover glass blank for electronic devices, and the said glass blank is cover glass for electronic devices. It is characterized by performing a shape processing step of processing into the shape of.
  • the manufacturing method of the cover glass for electronic devices of this invention maintains the surface state of the main surface of the glass blank manufactured by the manufacturing method of the said cover glass blank for electronic devices, and the main surface of the said glass blank is for electronic devices.
  • a shape processing step of processing the outer peripheral shape of the glass blank into the outer peripheral shape of the cover glass for electronic equipment is performed so as to be the main surface of the cover glass.
  • the method for producing an electronic device cover glass according to the present invention is characterized in that an electronic device cover glass is produced using the electronic device glass blank obtained by the method for producing an electronic device cover glass blank.
  • a cover glass blank for electronic equipment and a cover glass for electronic equipment that are suitable for small-quantity, multi-product production.
  • the figure which shows the structure of the cover glass for portable devices of embodiment The figure which shows the flow of one Embodiment of the manufacturing method of the cover glass for portable devices of embodiment.
  • a cover glass blank for a mobile device and a cover glass for a mobile device will be described as examples of the cover glass blank for an electronic device and the cover glass for an electronic device, respectively.
  • (1) First Embodiment (1-1) Cover Glass of Embodiment The configuration of the cover glass of the present embodiment will be described with reference to FIG. In FIG. 1, (a) is a perspective view of the cover glass of this embodiment according to one shape example, and (b) is a cross-sectional view of the cover glass of this embodiment.
  • the cover glass of the present embodiment is a glass substrate itself or a glass substrate on which a printed layer is formed (the latter structure is shown in FIG. 1).
  • a preferred usage of the cover glass of the present embodiment is, for example, a cover glass used for a display screen of a portable electronic device, particularly a mobile phone (mobile device). Therefore, the cover glass of the present embodiment needs to be a glass that is thin and has high strength so as to satisfy the specifications for the device drop or the operation input to the display screen (operation input as a touch panel function). For this reason, the cover glass of this embodiment consists of glass material containing the alkali metal oxide which can be chemically strengthened by an ion exchange process.
  • a known glass material such as aluminosilicate glass containing SiO 2 , Al 2 O 3, and at least one alkali metal oxide selected from Li 2 O and Na 2 O, and soda lime glass are used. It is preferable to use it.
  • the aluminosilicate glass includes 62% by weight to 75% by weight of SiO 2 and 5% by weight to 15% by weight from the practical viewpoints such as plate glass manufacturability, mechanical strength, and chemical durability.
  • A1 2 O 3 , 0-8 wt% Li 2 O, 4 wt% -16 wt% Na 2 O, 0-6 wt% K 2 O, 0 wt% -12 wt% ZrO 2 and 0 to 6% by weight of MgO are more preferable.
  • a compressive stress layer 10U and a compressive stress layer 10V are formed on the surface layer portions on the front surface side and the back surface side of the glass substrate 10 of the present embodiment, respectively.
  • the compressive stress layer 10U and the compressive stress layer 10V are altered layers in which a part of the alkali metal originally contained in the glass material constituting the glass substrate is replaced with an alkali metal having a larger ionic radius.
  • sodium ions contained in the glass material constituting the glass substrate of this embodiment are replaced with potassium ions.
  • the thickness of the compressive stress layers 10U and 10V is appropriately selected according to the use of the glass substrate, from the viewpoint of ensuring the scratch resistance of the main surfaces 10T and 10B and the impact resistance of the glass substrate 10, It is preferably 10 ⁇ m or more, more preferably 30 ⁇ m or more, and further preferably 40 ⁇ m or more.
  • the upper limit of the thickness of the compressive stress layers 10U and 10V is not particularly limited. It should be noted that the time required for the ion exchange process is increased, and the spontaneous crushing (self-destruction) during the production of the glass substrate 10 due to the deterioration of the stress balance of both main surfaces at the time of cutting by outer shape processing (cutting processing, wet etching) is prevented.
  • the thickness is preferably 100 ⁇ m or less, and more preferably 70 ⁇ m or less. Further, the thickness of the compressive stress layer 10U and the thickness of the compressive stress layer 10V may be different. However, in this case, the stress balance on both main surfaces 10T and 10B of the glass substrate 10 is lost, and the glass substrate 10 is likely to warp. Therefore, normally, the thickness of the compressive stress layer 10U and the thickness of the compressive stress layer 10V are preferably substantially the same.
  • the thickness T of the glass substrate 10 is not particularly limited, but it is usually preferably 1 mm or less from the viewpoint of suppressing an increase in the weight of various devices using the glass substrate 10 and reducing the thickness of the device. The following is more preferable.
  • board thickness shall be 0.2 mm or more from a viewpoint of ensuring the mechanical strength of the glass substrate 10.
  • the glass substrate 10 of this embodiment may be comprised only from the main body of the glass substrate 10, as shown in FIG. 1 according to the use application of the glass substrate 10, both main surface 10T of a glass substrate. , 10B, one or more decorative layers 20 may be provided.
  • the decorative layer 20 is represented by (1) an AR coat (anti-reflection coat, anti-glare coat, half mirror coat, layer having optical functions such as a polarizing film), and (2) an ITO (Indium Tin Oxide) film. Examples include a layer having an electrical function such as a transparent electrode film, and (3) a layer having a function of improving aesthetics such as a printed layer, etc.
  • a plurality of types of decorative layers 20 are laminated and patterned. By doing so, a function as a touch panel can be added to the glass substrate 10.
  • FIG. 2 is a flowchart showing a manufacturing process of a cover glass for a portable device.
  • a cover glass for portable devices first, a molten glass is press-molded in a press-molding process to produce a glass blank (step S10).
  • shape processing is performed on the glass blank obtained by press molding to produce a glass substrate having a desired shape (step S20).
  • the glass substrate is chemically strengthened to form a compressive stress layer on the surface layer portion of the glass substrate (step S30).
  • a decorative layer consisting of a single layer or multiple layers is provided on the surface of the glass substrate as required (step S40).
  • each step will be described in detail.
  • FIG. 3 is a plan view of an apparatus used in press molding.
  • the apparatus 101 includes four sets of press units 120, 130, 140, 150 and a cutting unit 160.
  • the cutting unit 160 is provided on the path of the molten glass flowing out from the molten glass outlet 111.
  • the apparatus 101 drops a lump of molten glass (hereinafter also referred to as a gob) cut by the cutting unit 160, and then sandwiches the lump between a pair of mold surfaces facing each other from both sides of the lump dropping path.
  • a glass blank is formed by pressing.
  • the apparatus 101 is provided with four sets of press units 120, 130, 140, and 150 every 90 degrees with a molten glass outlet 111 as a center.
  • Each of the press units 120, 130, 140, and 150 is driven by a moving mechanism (not shown) and can advance and retreat with respect to the molten glass outlet 111. That is, a catch position (a position where the press unit 140 is drawn with a solid line in FIG. 3) located immediately below the molten glass outlet 111 and a retreat position (the press unit 120 in FIG. 3) away from the molten glass outlet 111.
  • a catch position a position where the press unit 140 is drawn with a solid line in FIG. 3 located immediately below the molten glass outlet 111
  • a retreat position the press unit 120 in FIG. 3
  • the cutting unit 160 is provided on the molten glass path between the catch position (gob capture position by the press unit) and the molten glass outlet 111, and cuts out an appropriate amount of molten glass flowing out of the molten glass outlet 111. To form a lump of molten glass.
  • the cutting unit 160 has a pair of cutting blades 161 and 162. The cutting blades 161 and 162 are driven to intersect on the molten glass path at a fixed timing, and when the cutting blades 161 and 162 intersect, the molten glass is cut out to obtain gob. The obtained gob falls toward the catch position.
  • the press unit 120 includes a first die 121, a second die 122, a first drive unit 123, and a second drive unit 124.
  • Each of the first mold 121 and the second mold 122 is a plate-like member having a surface for press molding a gob. The normal direction of the two surfaces is a substantially horizontal direction, and the two surfaces are arranged to face each other in parallel.
  • the first drive unit 123 moves the first mold 121 forward and backward with respect to the second mold 122.
  • the second drive unit 124 moves the second mold 122 forward and backward with respect to the first mold 121.
  • the first drive unit 123 and the second drive unit 124 are mechanisms that rapidly bring the surface of the first drive unit 123 and the surface of the second drive unit 124 into proximity, such as a mechanism that combines an air cylinder, a solenoid, and a coil spring, for example. Have. Note that the structure of the press units 130, 140, and 150 is the same as that of the press unit 120, and a description thereof will be omitted.
  • the falling gob is sandwiched between the first die and the second die by the drive of the first drive unit and the second drive unit, and is formed to a predetermined thickness. At the same time, it is rapidly cooled to produce a circular glass blank G.
  • the press unit moves to the retracted position, the first mold and the second mold are pulled apart, and the molded glass blank G is dropped.
  • a first conveyor 171, a second conveyor 172, a third conveyor 173, and a fourth conveyor 174 are provided below the retreat positions of the press units 120, 130, 140, and 150, respectively.
  • Each of the first to fourth conveyors 171 to 174 receives the glass blank G falling from the corresponding press unit, and conveys the glass blank G to the next process apparatus (not shown).
  • the press units 120, 130, 140, and 150 are sequentially moved to the catch position, and are moved to the retreat position with the gob interposed therebetween. For this reason, the glass blank G can be continuously formed without waiting for the cooling of the glass blank G in each press unit.
  • FIG. 4 (a) to 4 (c) illustrate the press molding using the apparatus 101 more specifically.
  • 4A is a diagram showing a state before the gob is made
  • FIG. 4B is a diagram showing a state where the gob is made by the cutting unit 160
  • FIG. It is a figure which shows the state by which the glass blank G was shape
  • the molten glass material L G is continuously flowing out.
  • the cutting unit 160 by driving the cutting unit 160 at predetermined timing, cutting the molten glass material L G by the cutting blades 161 and 162 ( Figure 4 (b)).
  • disconnected molten glass becomes a substantially spherical gob GG with the surface tension.
  • the outflow amount per hour of the molten glass material LG and the driving interval of the cutting unit 160 can be appropriately adjusted according to the target size of the glass blank G and the volume determined from the plate thickness.
  • Made gob G G falls down toward the gap between the first die 121 of the pressing unit 120 of the second die 122.
  • the first driving unit 123 and The second drive unit 124 (see FIG. 4) is driven.
  • the gob GG is captured (caught) by the first mold 121 and the second mold 122.
  • press surface 121a of the first die 121 and the press surface 122a of the second die 122 are close to each other at a minute interval, and the press surface 121a of the first die 121 and the second die 122 are in close proximity. gob G G sandwiched between the press surface 122a is formed into a thin plate.
  • the press surface 121a of the first die 121 and the press surface 122a of the second die 122 are maintained.
  • the surface 122a is provided with a protrusion 121b and a protrusion 122b. That is, when the protrusion 121b and the protrusion 122b abut each other, the distance between the press surface 121a of the first die 121 and the press surface 122a of the second die 122 is maintained constant, and the glass blank G A space corresponding to the outer shape is formed.
  • the first die 121 and second die 122, the temperature adjusting mechanism (not shown) is provided with the temperature of the first die 121 and second die 122, the glass transition temperature of the molten glass L G (Tg ) Is kept at a temperature sufficiently lower than.
  • the flatness of the glass blank obtained after press molding becomes better as the temperature difference between the pressing surface 121a of the first die 121 and the pressing surface 122a of the second die 122 is smaller.
  • the pair of molds (the press surface 121a of the first mold 121 and the second mold 122) for realizing the flatness required for the cover glass for portable devices.
  • the maximum value of the temperature difference (absolute value) between the press surfaces 122a) is known. Therefore, by controlling the temperature difference between the pair of molds to be equal to or less than the maximum value, the flatness required for the cover glass for portable devices can be realized. For example, if the flatness required for the cover glass for portable devices is 8 ⁇ m, press molding is performed in a state where the temperature difference between the pair of molds is within 10 ° C. The flatness of the glass blank produced when the temperature difference between the pair of molds is 0 ° C. is the best. However, the temperature difference may be appropriately determined from the correlation according to the flatness required for the cover glass for portable devices.
  • the first die 121 and second die 122 is a gob G G
  • the time to complete confinement is as short as about 0.06 seconds. Therefore, the gob G G is formed into a substantially circular shape spread within a very short period of time along the pressing surface 122a of the press surface 121a and the second die 122 of the first die 121, it is further rapidly cooled To solidify as amorphous glass. Thereby, the glass blank G is produced.
  • the size of the glass blank G formed in the present embodiment is, for example, about 20 to 200 mm in diameter (or the length of one side) depending on the size of the target cover glass.
  • the glass blank G is formed in a form in which the press surface 121a of the first die 121 and the press surface 122a of the second die 122 are shape-transferred.
  • the flatness and smoothness of the pressed surface are preferably set to be equivalent to those of the target cover glass.
  • a surface processing step for the glass blank G that is, a grinding and polishing step can be omitted. That is, the glass blank G molded in the press molding method of the present embodiment may have the same thickness as the target thickness of the cover glass finally obtained.
  • the glass blank G is a circular plate having a thickness of 0.2 to 1.1 mm.
  • the surface roughness of the press surface 121a and the press surface 122a is adjusted so that the arithmetic average roughness Ra of the glass blank G is 0.001 to 0.1 ⁇ m, preferably 0.0005 to 0.05 ⁇ m. Is done.
  • the press unit 120 quickly moves to the retracted position, and instead, the other press unit 130 moves to the catch position. press of the gob G G is performed.
  • the first mold 121 and the second mold 122 are in a closed state until the glass blank G is sufficiently cooled (at least until the temperature becomes lower than the bending point). I'm particular. Thereafter, the first driving unit 123 and the second driving unit 124 are driven to separate the first mold 121 and the second mold 122, and the glass blank G falls off the press unit 120 and is at the lower part. It is received by the conveyor 171 (see FIG. 3).
  • the first mold 121 and the second mold 122 are closed within a very short time of 0.1 second (about 0.06 seconds), and the first mold 121 is pressed.
  • the molten glass comes into contact with the entire surface 121a and the entire pressing surface 122a of the second die 122 almost simultaneously.
  • the press surface 121a of the first die 121 and the press surface 122a of the second die 122 are not locally heated, and the press surface 121a and the press surface 122a are hardly distorted.
  • the temperature distribution of the molten glass to be formed becomes substantially uniform.
  • the flatness of the main surface of the produced glass blank G is improved as compared with a glass blank produced by conventional vertical press molding.
  • the gob G G substantially spherical is formed by cutting the outflowing molten glass L G.
  • the viscosity of the molten glass material L G, smaller with respect to the volume of the gob G G to be Kiridaso is glass is only to cut the molten glass L G is cut not become nearly spherical, gob Cannot be made.
  • a gob forming mold for making a gob is used.
  • FIGS. 5A to 5C are diagrams for explaining a modification of the embodiment shown in FIG. In this modification, a gob forming mold is used.
  • FIG. 5A is a diagram showing a state before the gob is made
  • FIG. 5B is a diagram showing a state where the gob GG is made by the cutting unit 160 and the gob forming mold 180.
  • 5 (c) is a diagram showing a state where the glass blank G was made by press-molding the gob G G.
  • the press unit 120 further includes blocks 181 and 182.
  • the blocks 181 and 182 are disposed so as to be displaceable in the directions approaching and separating from each other.
  • the block 181 and 182 by a driving means (not shown) is driven to open and close jointly the path of the molten glass L G. Path of the molten glass L G is closed by closing the block 181 and 182 along the path of the molten glass L G. Then, the concave portion 180C made at block 181 and 182, mass is cut by the cutting unit 160 molten glass L G is received. Thereafter, as shown in FIG. 5 (b), by the block 181, 182 is opened, the molten glass L G became spherical falls toward the pressing unit 120 at a time in the recess 180C, the molten glass L G but the gob G G of the spherical. Gob G G Spherical, falling midway, as shown in FIG. 5 (c), by the first die 121 is sandwiched by press molding and a second mold 122, the circular glass blank G Produced.
  • FIG. 6 (a) ⁇ (d) device 101, without using the cutting unit 160 shown in FIG. 5 (a) ⁇ (c) , the gob-forming 180, the molten glass L G
  • a moving mechanism that moves in the upstream direction or the downstream direction along the route may be used.
  • 6 (a) to 6 (d) are diagrams illustrating a modification using the gob forming mold 180.
  • FIG. FIG 6 (a), (b) is a diagram showing a state before the gob G G is made
  • FIG. 6 (c) a diagram showing a state in which the gob G G were made by the gob forming type 180
  • FIG. 6 (d) is a diagram showing a state where the glass blank G was made by press-molding the gob G G.
  • FIG. 6 (a) it receives the molten glass L G of the recess 180C formed jointly by block 181 and 182 flows out from the molten glass outflow port 111. Then, as shown in FIG. 6 (b), it is moved quickly blocks 181 and 182 at a predetermined timing to the downstream side of the flow the molten glass L G. Thus, the molten glass L G is cut, the gob G G is formed. Thereafter, the blocks 181 and 182 are separated at a predetermined timing as shown in FIG. Thus, the molten gob G G held in block 181 and 182, it falls at a time. Gob G G becomes spherical due to the surface tension of the molten glass L G. Gob G G Spherical, falling midway, as shown in FIG. 6 (d), by the first die 121 is sandwiched by press molding and a second mold 122, the circular glass blank G Produced.
  • FIG. 7A is a diagram showing a state before the heated optical glass lump is formed
  • FIG. 7B is a diagram showing a state in which the optical glass lump is dropped
  • FIG. ) Is a diagram showing a state in which a glass blank G is made by press-molding a lump of optical glass.
  • the apparatus 201 conveys the optical glass block CP to the position above the press unit 220 by the glass material gripping mechanism 212.
  • the gob G G when cutting the gob G G by a pair of cutting blades 161 and 162, as cut marks on the periphery of the glass blank to be molded is positioned, it is preferable to cut the gob G G.
  • the cutting mark caused in the gob G G is in a falling continued positioned above, without changing the position of the cutting marks in the gob G G even during pressing, as a result, the peripheral edge of the glass blank G (in the press above the peripheral edge of) has been found that cutting marks to arise.
  • the thickness of the upper cutting blade 161 is 1.5 mm
  • the thickness of the lower cutting blade 162 is 1.0 mm.
  • FIG. 8 is a diagram similar to FIG. 8 (a) is a side view before the molten glass material L G and the cutting unit 160 is in contact.
  • FIG. 8 (b) the cutting unit 160 is a side view after cutting out the molten glass material L G.
  • 8 (c) is a side view illustrating a state where the pressing unit 120 is press molded mass G G of the molten glass.
  • FIG. 8D is a side view of the state where the molten or softened glass protruding from the press unit is removed.
  • the apparatus of this modification is further provided with a cutting blade 165, and the configuration other than the cutting blade 165 is the same as the configuration shown in FIG.
  • the cutting blade 165 of the present modification is a blade that is driven to be able to advance and retreat in the horizontal direction at the upper ends of the first die 121 and the second die 122, and glass that has been melted or softened in a state of protruding from the press unit 120. It is provided for cutting.
  • FIGS. 8A and 8B are the same as FIGS. 4A and 4B, respectively.
  • the first driving unit 123 second driving unit 124 and the first die 121 and second die 122 To drive.
  • the portion that does not include the cutting mark T of gob G G between the first die 121 and the second die 122 is captured (caught), the cutting mark T is It will be in the state which protruded from the press unit 120.
  • the cutting blade 165 removes the molten or softened glass protruding from the press unit 120. Note that the shape and material of the cutting blade 165 are not limited as long as the glass protruding from the press unit 120 can be removed.
  • FIG. 9A is a plan view of the first die 321 and the second die 322 included in the press unit 320 according to this modification.
  • FIG. 9B is a side view of the press unit 220 of the present embodiment.
  • the first mold 321 and the second mold 322 of the present embodiment have a shape obtained by cutting a part of a substantially circular arc in a straight line.
  • the first mold 321 and the second mold 322 are formed such that a straight line portion L obtained by cutting out a part of an arc in a straight line is positioned vertically upward. As shown in FIG.
  • the first mold 321 and the second mold 322 face each other in the open state in a state where the normal direction of the surface for press molding the gob is inclined with respect to the horizontal direction.
  • the first mold 321 is maintained at a constant distance between the press surface 321a of the first mold 321 and the press surface 322a of the second mold 322, and the first unit 321 is formed so as to form a plate-like space in the press unit 320.
  • the press surface 321a of the mold 321 and the press surface 322a of the second mold 322 are provided with a protrusion 321b and a protrusion 322b, respectively.
  • FIG. 10 is a diagram similar to FIG. That is, FIG. 10 (a) is a plan view before the molten glass material L G and press unit 320 are in contact. 10 (b) is a side view after the press unit 320 is cut out molten glass material L G. Figure 10 (c) is a side view illustrating a state where the pressing unit 320 is press molded mass G G of the molten glass. As shown in FIG. 10 (a), molten glass material L G is continuously flowing out from the molten glass outflow port 111. At this time, each of the first mold 321 and the second mold 322 moves in the horizontal direction as indicated by arrows in FIG.
  • the first mold 321 and the second mold 322 are arranged so that the first mold 321 and the second mold 322 are closed as shown by arrows in FIG.
  • the lower end of each of the two molds 322 moves.
  • the gob GG is captured (caught) between the first mold 321 and the second mold 322, and the glass blank G is manufactured.
  • the gob G G is press-molded. For this reason, no cut marks are generated in the glass blank G.
  • step S20 Shape processing step
  • the shape processing step (B) will be described.
  • the glass blank produced by the press molding process of the previous process can have extremely high flatness and smoothness, the distortion generated in the glass blank by reheating the glass blank.
  • the glass blank produced by the press molding process may be processed into the desired shape of the cover glass for portable equipment by this shape processing process without performing the annealing process for removing the film.
  • the distortion of the surface layer portion of the glass blank is a compressive stress layer.
  • the distortion of the surface layer portion of the glass blank is a compressive stress layer. This is because when a lump of molten glass is pressed by a pair of molds, heat is transferred from the molten glass to the mold and the surface side of the molten glass cools and hardens before the center side, and the center side of the molten glass is the surface layer side. It is formed by a difference in shrinkage due to cooling and setting after a delay (that is, it corresponds to a compressive stress layer by physical strengthening).
  • a shape processing process is a process of processing the glass blank obtained at the press molding process into the desired shape according to the external shape of the glass substrate for portable devices, and obtaining a glass substrate.
  • Examples of a cutting method for processing a glass blank into a desired shape include etching and scribing.
  • a cutting line linear scratch
  • a cutting line that matches the contour of the desired shape by a scriber made of super steel alloy or diamond particles on the surface of the glass blank. Is provided. Then, only a desired area
  • the shape processing step using the cutting method by etching includes the following steps: (b-1) etching-resistant film forming step, (b-2) patterning step, and (b-3) cutting step.
  • (b-1) etching-resistant film forming step includes the following steps: (b-1) etching-resistant film forming step, (b-2) patterning step, and (b-3) cutting step.
  • the shape processing process using the cutting method by etching will be described.
  • Etching-resistant film forming step an etching-resistant film is formed on at least one surface of the glass blank.
  • This etching resistant film is usually formed on both surfaces of the glass blank. However, when only one surface is brought into contact with the etching solution in the subsequent cutting step, the etching resistant film only needs to be formed on the one surface. . In the following description, it is assumed that the etching resistant film is formed on both surfaces of the glass blank.
  • the etching-resistant film can be appropriately selected as long as it can be partially removed by a patterning process in a later patterning process and has a property that is not dissolved / removed in an etching solution used in a cutting process. .
  • the resist film As such an etching resistant film, it is preferable to use a resist film that is hardly soluble or insoluble in at least a hydrofluoric acid aqueous solution.
  • the resist film in the patterning process, can be patterned by an exposure process using a photomask and a development process using a developer, and can be cut using an etching solution in the cutting process.
  • (B-2) Patterning Step In the patterning step, at least the etching resistant film is patterned. As a result, the etching resistant film other than the region corresponding to the shape in the planar direction of the finally produced glass substrate is removed from the etching resistant film covering the entire surface of the glass blank.
  • a patterning method for the etching-resistant film photolithography that is performed by combining the above-described exposure and development can be typically used.
  • the patterning step may be performed on at least one side of a glass blank having an etching resistant film formed on both sides, or may be performed on both sides.
  • (B-3) Cutting Step the glass blank is cut into small pieces by etching the surface of the glass blank on which the patterned etching resistant film is provided in contact with the etching solution.
  • the etching process is usually performed by immersing a glass blank in an etching solution.
  • the etching solution is not particularly limited as long as it contains at least hydrofluoric acid. If necessary, other acids such as hydrochloric acid and various additives such as a surfactant may be added.
  • step S30 Chemical strengthening process
  • a chemical strengthening process step S30
  • a plurality of glass substrates processed into a desired shape by the shape processing step are loaded into a cassette (holder), and the cassette is immersed in a chemical strengthening treatment liquid containing a molten salt.
  • a chemical strengthening treatment liquid containing a molten salt containing a molten salt.
  • the composition and temperature of the molten salt and the immersion time can be appropriately selected according to the glass composition of the glass substrate, the thickness of the compressive stress layer formed on the surface layer portion of the glass substrate, etc.
  • the treatment temperature of the chemical strengthening treatment liquid is usually 500 ° C. or lower. This is because the high-temperature ion exchange method in which ion exchange is performed in the temperature range above the annealing point of the glass does not provide as much strength as the low-temperature ion exchange method, and the glass surface is eroded by the molten salt during the strengthening treatment.
  • the composition and temperature of the molten salt and the immersion time are preferably selected from the ranges exemplified below.
  • -Composition of molten salt Potassium nitrate or a mixed salt of potassium nitrate and sodium nitrate
  • -Temperature of molten salt 320 ° C to 470 ° C ⁇ Immersion time: 3 to 600 minutes
  • step S40 decoration layer formation process
  • the decorative layer formation process for forming the decoration layer 20 with respect to one main surface of the glass substrate 10 chemically strengthened is performed (step S40).
  • the decorative layer 20 is formed on the main surface of the glass substrate 10 by various known printing methods such as screen printing or a known film forming method.
  • Known film formation methods include, for example, known liquid phase film formation methods such as dipping method, spray coating method, sol-gel coating method, plating method, vacuum evaporation method, sputtering method, CVD (Chemical Vapor Deposition) method, etc.
  • the vapor phase film forming method can be used.
  • the method for manufacturing a cover glass for a portable device of the present embodiment includes a press molding step of press molding a lump of molten glass using a pair of molds. Therefore, if the surface roughness of the press surfaces of the pair of molds is set to a good level (for example, the surface roughness required for a cover glass for portable devices), the surface roughness can be obtained by press molding. The shape is transferred as the surface roughness of the glass blank. For this reason, the surface roughness of a glass blank can be made into a favorable level.
  • the portable device is based on the correlation between the temperature difference between the opposed positions of the pair of molds when the molten glass is press molded and the flatness of the glass blank obtained after the press molding. While determining the temperature difference between the pair of molds that can achieve the flatness required for the cover glass for the glass, while controlling the temperature of the pair of molds so that the temperature of the pair of molds is within the above-described temperature difference, Press molding may be performed. Therefore, the glass blank obtained by the press molding process of this embodiment can make the surface roughness and flatness of the main surface into the level calculated
  • the outer peripheral shape of the glass blank is changed to the outer periphery of the cover glass for portable devices so that the surface state of the main surface of the glass blank is maintained and the main surface of the glass blank becomes the main surface of the cover glass for portable devices.
  • the glass substrate that has been processed into a predetermined shape based on this glass blank is chemically strengthened, but in this embodiment, the flatness of the glass substrate is not deteriorated by the chemical strengthening. Therefore, the finally obtained cover glass for portable devices is thin, has high mechanical strength, and has a higher flatness than before.
  • size of the glass blank produced in a press molding process is near the magnitude
  • the shape of the case of a portable device is generally a three-dimensional shape, but it is difficult to produce a three-dimensional shape cover glass for a portable device based on a plate glass obtained by a float method or a downdraw method. That is, in order to produce a cover glass for a mobile device having a three-dimensional shape based on a plate glass obtained by a float method or a downdraw method, a mold that can re-melt the plate glass and obtain a desired three-dimensional shape. It is difficult to produce unless molten glass is poured into the glass.
  • the press molding method described in the first embodiment by preparing a mold that matches the outer shape of the desired cover glass for portable equipment, it is possible to avoid remelting, and to achieve high flatness and Since smoothness is obtained, it is suitable for producing a cover glass for a portable device for the purpose of protecting the casing of the portable device.
  • FIG. 11 shows an example of the external shape of a cover glass for a three-dimensional portable device.
  • the cover glass for a mobile device illustrated in FIG. 11 has a generally U-shaped form and covers the case of the mobile device from the back side.
  • FIG. 12 is a diagram specifically illustrating a press molding method for producing the glass blank for the cover glass for portable devices illustrated in FIG. 11.
  • FIG. 12A is a diagram showing a state before the gob is made
  • FIG. 12B is a diagram showing a state where the gob is made by the cutting unit 160
  • FIG. It is a figure which shows the state by which the glass blank G was shape
  • a first die 421 and a second die 422 having a shape capable of obtaining a closed space corresponding to a target three-dimensional glass blank G at the time of closing are used.
  • the same closed space as the shape shown in FIG. 11 is obtained when the mold is closed.
  • the first mold 421 has a structure protruding in the pressing direction (convex structure)
  • the second mold 422 has a structure recessed in the pressing direction (concave structure).
  • the shape of the mold it can be appropriately changed according to the design of the cover glass, and by changing the shape of the mold, such as partially bending the glass blank in the plate thickness direction, the shape of the cover glass The degree of freedom can be improved.
  • the gob G G made to fall to the first mold 421 of the press unit 420 toward the gap between the second mold 422.
  • the first mold 421 When the gob G G is captured (caught) by the second mold 422.
  • the outer peripheral surface 421b of the press surface 421a of the first die 421 and the outer peripheral surface 422b of the press surface 422a of the second die 422 abut.
  • the press surface 421a of the first mold 421 and the gob G G sandwiched between the press surface 422a of the second mold 422 and solidified is rapidly cooled, the shape and the same glass blank shown in FIG. 11 Molded into G.
  • the surface roughness of the press surface 421a and the press surface 422a is preferably 0.0005 ⁇ m so that the arithmetic average roughness Ra of the glass blank G is 0.001 ⁇ m to 0.1 ⁇ m. Can be adjusted to be 0.05 ⁇ m, and the smoothness of the surface of the glass blank becomes extremely high. Therefore, the grinding and polishing steps after press molding are not performed on the main surface. That's it.
  • a cover glass for a portable device for the purpose of protecting the casing of the portable device.
  • the required value varies depending on the model and size used, the flatness generally required for a cover glass for portable devices is preferably 20 ⁇ m or less per 8 cm length.
  • Example 10 As a glass composition, 63.5 wt% SiO 2 , 8.2 wt% A1 2 O 3 , 8.0 wt% Li 2 O, 10.4 wt% Na 2 O, and 11. A molten glass material containing 9% by weight of ZrO 2 was prepared, and the diameter was 90 mm and the thickness was 0 using the press molding method of the first embodiment of the present invention (method using the apparatus of FIGS. 3 and 4). A 7 mm glass blank was produced. Melting temperature of the molten glass material L G discharged from the glass outlet 111 is 1300 ° C., the viscosity of the molten glass material L G at this time is 700 poise.
  • the surface roughness (arithmetic average roughness Ra) of the press surfaces of the first die and the second die was set to 0.01 ⁇ m to 1 ⁇ m.
  • Molten glass material L G discharged from the molten glass outflow port 111 is cut by the cutting unit 160, and the gob G G having a diameter of about 20mm is formed.
  • the gob G G, a load 3000kgf by press unit, its temperature is molten glass until the material becomes a glass transition temperature (Tg) of less than (about 3 seconds) press, the glass blank with a diameter of 90mm was formed. This glass blank was cut into small pieces of 45 mm ⁇ 80 mm.
  • the temperature difference between the first die and the second die in each press unit is as follows to achieve this flatness: The temperature was within 10 ° C. Specifically, the temperature of the first mold was 420 ° C., and the temperature of the second mold was 411 to 429 ° C. Next, the glass blank was immersed in the molten salt for chemical strengthening, and a compressive stress layer of about 40 ⁇ m was formed on both surfaces of the glass blank.
  • the immersion time was appropriately adjusted while maintaining the temperature of the molten salt within the range of 320 ° C to 360 ° C.
  • the surface roughness is represented by an arithmetic average roughness Ra defined by JIS B0601: 2001 (or ISO 4287: 1997).
  • a roughness measuring machine SV- manufactured by Mitutoyo Corporation It is measured by 3100 and can be calculated by a method defined in JIS B0633: 2001 (or ISO 4288: 1996).
  • the roughness is 0.03 ⁇ m or less, for example, it can be measured with a scanning probe microscope (atomic force microscope; AFM) nanoscope manufactured by Japan Veeco and calculated by a method defined in JIS R1683: 2007. .
  • the arithmetic average roughness Ra when measured at a resolution of 512 ⁇ 512 pixels in a 1 ⁇ m ⁇ 1 ⁇ m square measurement area was used.
  • the evaluation criteria of the surface roughness shown in Table 1 are as follows. ⁇ : Ra is 0.01 ⁇ m or less ⁇ : Ra is larger than 0.01 ⁇ m and 0.1 ⁇ m or less X: Ra is larger than 0.1 ⁇ m
  • the cover glass blank for electronic devices manufactured with the manufacturing method of this invention is a touch sensor as a base material of the cover glass for touch sensors which is a cover member with respect to the internal substrate of a touch sensor other than the cover glass blank for portable devices. It can be used for a cover glass blank.
PCT/JP2012/001840 2011-03-30 2012-03-16 電子機器用カバーガラスブランクの製造方法および電子機器用カバーガラスの製造方法 WO2012132293A1 (ja)

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