JP2014009118A - Method for manufacturing glass substrate used for electronic device cover glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass substrate used for an electronic device cover glass capable of suppressing a blank laminate formed by laminating glass substrates from deforming and improving dimension accuracy of the glass substrates.SOLUTION: A method for manufacturing a glass substrate used for an electronic device cover glass includes: a laminating step of forming a blank laminate 120 formed by laminating and adhering together a plurality of glass blanks 110; and a cutting step of forming laminate blocks 130 each having a small main surface area by cutting the blank laminate 120. In the method, an adhesive agent 114 for adhering the glass blanks 110 together is a photocurable resin, and in the laminating step, the curing of the adhesive agent 114 is advanced from both sides of the blank laminate by irradiating both main surfaces of the blank laminate 120 with light such that the light reaches the center region of the thickness of the blank laminate at the same intensity from the directions orthogonal to both main surfaces.

Description

  The present invention relates to 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 a touch sensor such as a pointing device. The present invention relates to a method for manufacturing a glass substrate of a cover glass for equipment.

  In mobile devices including smartphones, and mobile devices such as tablet terminals, slate PCs (Personal Computers), and PDAs (Personal Digital Assistants), a cover glass is arranged outside the display device to protect the display device such as a liquid crystal display. The In addition, in touch sensors (pointing devices) of stationary devices such as ATMs and ticket vending machines, a cover glass is arranged to protect the transparent conductive film (ITO: Indium-tin-oxide) for sensor substrates and touch panels. Is done.

  In general, a cover glass is manufactured by extracting a glass substrate having an arbitrary shape from a large single glass plate and processing the extracted glass substrate. As a method of extracting a glass substrate from a glass base plate, a method of processing by mechanical processing means is known (for example, Patent Document 1). In Cited Document 1, the stacked material plate glass (glass base plate) is fixed by a peelable fixing material to form a material glass block (base plate laminate), and this is cut by a disk cutter to reduce the area. It is described that a divided glass block (laminated block) is formed. Further, it is described that as the fixing material, it is preferable to use a resin having photocurability that is cured by ultraviolet rays and thermoplasticity that is softened by heating.

JP 2009-256125 A

  In recent years, with the increase in demand for portable devices, the demand for cover glass has also increased rapidly. Under such a background, the cover glass, for example, not only increases the strength to protect the display screen of a portable device, but also requires higher dimensional accuracy in order to improve the assembly accuracy when assembled to the main body side. ing. Moreover, since the request | requirement which gives waterproof property to a portable device is also increasing, the dimensional accuracy calculated | required by the cover glass in order to fully exhibit waterproofness is increasing more and more.

  By the way, when performing glass cutting and outer shape processing by laminating as described above, as many as possible are preferably laminated from the viewpoint of production efficiency as long as cutting and processing can be performed. However, as the number of stacked layers increases, the overall distortion (warp) is more likely to occur when stacked and fixed.

  In particular, the cover glass tends to be thinner due to the recent demand for thinner and lighter portable devices and the improvement of glass technology. For example, as a typical example of an electronic device, a cover glass for a touch panel display of a smartphone has a thickness of about 0.6 mm and is expected to become thinner in the future. When the thickness is reduced in this way, naturally the rigidity of the glass base plate is lowered, so that the strain is more likely to occur.

  In order to cut a laminated body of glass plates stacked and fixed, it is necessary to fix them to a processing table. As a method of fixing to the processing table, a method of adhering to the processing table or adsorbing by a vacuum suction method is known. However, even if it is going to employ | adopt a vacuum adsorption method, if the distortion | strain has generate | occur | produced in the laminated body, a clearance gap will arise between a laminated body and a process table. Then, the suction force is reduced due to air leakage, and a shift occurs during cutting, which makes it difficult to perform the cutting process. Here, vacuum suction means that a workpiece (laminate) is suction-fixed to a processing table using negative pressure.

  Moreover, even if it is cut by bonding, if the cutting and outer shape processing are performed in a state where the glass substrate stack is distorted, the size is reduced between the glass substrate above the laminated block and the glass substrate below. Differences will occur. Specifically, the size of the glass substrate outside the warp becomes larger than that of the glass substrate inside the warp. Such a dimensional error (variation) of the glass substrate has a problem of hindering improvement in the dimensional accuracy of the cover glass.

  Moreover, even if there is distortion in the state of the base plate laminate, the distortion is resolved when the glass substrates are separated into individual glass substrates. Therefore, when cutting and outer shape processing are performed in a state where there is a strain, the end face of the laminated body is vertical, but after separating and returning to the flatness, the vertical degree of the end face of the glass substrate is lowered. Such a decrease in perpendicularity has a problem in that the appearance and waterproofness are deteriorated, and a sharp edge is likely to be chipped.

  In view of the above-described problems, the present invention provides a method for manufacturing a glass substrate for a cover glass for an electronic device that can suppress distortion of a substrate laminate in which glass substrates are laminated and can improve the dimensional accuracy of the glass substrate. It is aimed.

  As a result of extensive studies by the inventors in order to solve the above problems, the inventors have focused on the progress of curing of the adhesive. That is, when a photocurable resin is used for the adhesive, as described in Patent Document 1, it is cured by irradiating ultraviolet rays from above the laminated glass base plates. As a result, the integrated light quantity inevitably increases on the upper side of the base laminate, and curing progresses faster on the upper side. Then, residual stress is generated by shrinking the adhesive as it is cured, and residual stress is generated on the upper side before the lower side is cured. Therefore, further investigation was made and the present invention was completed.

  That is, a typical configuration of the present invention includes a laminating step for forming a base plate laminate in which a plurality of glass base plates are laminated and bonded, and a laminate block having a main surface area that is cut by cutting the base plate laminate. In the manufacturing method of a glass substrate of a cover glass for an electronic device including a cutting step to be formed, the adhesive that bonds the glass base plates to each other is a photocurable resin, and in the laminating step, both main surfaces of the base plate laminate The curing of the adhesive proceeds from both sides of the base laminate by irradiating both main surfaces with light so as to reach the thickness center region of the base laminate with equal strength from the direction perpendicular to It is characterized by that.

  According to the above configuration, since the curing of the adhesive can proceed equally from both sides of the base plate laminate, the residual stress due to the shrinkage of the adhesive becomes even on the front and back, reducing the strain of the base laminate. be able to. Therefore, it is possible to suppress a dimensional error above and below the laminated block after the cutting process and a decrease in the verticality of the end faces of the glass substrates. In addition, when irradiating light, you may irradiate from both upper and lower sides with a base-plate laminated body placed flat, or you may irradiate from both right and left in the state which supported the base-plate laminated body upright.

  In the laminating process, glass plates and adhesives are alternately stacked on a rigid plate that transmits light, and a plate with the same light transmittance as the plate is placed on the laminated glass plate. You may irradiate with light.

  The said structure is a case where a glass base plate is mounted horizontally and laminated | stacked. According to the above-described configuration, the integrated light amounts on both sides can be easily matched, and the deformation can be further suppressed by the weight and rigidity, so that the strain can be further reduced.

  In the laminating process, two rigid plates that transmit light are arranged along both main surfaces of the base plate laminate, and the base plate laminate and the plates are placed upright, and the base plate is formed by the two plates. You may irradiate light, applying a pressure so that a laminated body may be pinched | interposed.

  The said structure is a case where a glass base plate is laminated | stacked in the state stood | rightened vertically. According to the above configuration, the integrated light amounts on both sides can be easily matched, and the deformation is mechanically suppressed by the pressure and rigidity, so that the strain can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the distortion of the base-plate laminated body which laminated | stacked the glass base plate can be suppressed, and the manufacturing method of the glass substrate of the cover glass for electronic devices which can improve the dimensional accuracy of a glass substrate can be provided.

It is a figure explaining the cover glass for electronic devices. It is a flowchart explaining the manufacturing method of the glass substrate of the cover glass for electronic devices. It is a figure explaining a lamination process. It is a figure explaining a cutting process. It is a figure explaining a process table. It is a figure explaining other embodiment.

  Exemplary embodiments of the present invention will be described below 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 an external perspective view illustrating a cover glass for an electronic device. The cover glass for an electronic device manufactured by the manufacturing method according to the present invention is a mobile phone including a smartphone, a mobile device such as a tablet terminal, a slate PC (Personal Computer), or a PDA (Personal Digital Assistant), or a pointing device, ATM. It can be used as a cover glass for a touch sensor of a stationary apparatus such as a ticket vending machine or an electronic guide board. In the present embodiment, the glass substrate 100 will be described with reference to a cover glass for a mobile phone (mobile device).

  As shown in FIG. 1, the outer peripheral portion 102 of the glass substrate 100 is generally rectangular. Further, the glass substrate 100 is provided with openings 104 for speakers, buttons, and microphones, for example. Although the thickness of the glass substrate 100 is not particularly limited, it is usually preferably 1 mm or less, preferably 0.7 mm or less, from the viewpoint of suppressing weight increase of various devices using cover glass and thinning the device. More preferably. In addition, it is preferable that the lower limit of plate thickness shall be 0.1 mm or more from a viewpoint of ensuring the mechanical strength of a glass substrate. The outer shape of the glass substrate 100 can be appropriately set according to the portable device to be incorporated.

  The glass substrate 100 is cut out from a large glass base plate 110 as described later. The glass base plate 110 is formed directly from molten glass into a sheet shape, or a glass body molded to a certain thickness is molded to a predetermined thickness, and the main surface is polished to a predetermined thickness. Things can be used. In particular, when the glass base plate 110 that is molded directly from molten glass into a sheet is used, it is preferable because the main surface of the glass base plate 110 has a surface state without microcracks. Examples of the method for directly forming a sheet from molten glass include a downdraw method and a float method.

  The glass base plate 110 is preferably made of aluminosilicate glass, soda lime glass, borosilicate glass, transparent crystallized glass, or the like. Among these, an aluminosilicate glass containing SiO2, Al2O3, Li2O and / or Na2O is preferable. Li2O is a component for exchanging Na + ions and Li + ions in chemical strengthening. Na2O is a component for exchanging K + ions and Na + ions in chemical strengthening. ZrO2 is useful for increasing the mechanical strength. However, even materials other than aluminosilicate glass may be used as long as they can be chemically strengthened (they should contain at least one of Li + ions and Na + ions).

  FIG. 2 is a flowchart for explaining a method for manufacturing a glass substrate of a cover glass for electronic equipment, FIG. 3 is a diagram for explaining a lamination process, and FIG. 4 is a diagram for explaining a cutting process. Hereinafter, the manufacturing method of the glass substrate of the cover glass for electronic devices is demonstrated along the flowchart of FIG. 2, referring FIG. 3 and FIG.

Steps 200 to 206 are steps for laminating the glass base plate 110.
First, a rigid plate 112 that transmits light is installed (step 200, FIG. 3A). The plate 112 preferably has a high light transmittance, and preferably has a light refractive index close to that of the glass base plate 110. Moreover, what has the rigidity which does not produce distortion by the residual stress of an adhesive agent is preferable. As a simple example, the plate 112 may be made of the same material as the glass base plate 110 and have a sufficient thickness to obtain rigidity.

  Next, a large-sized glass base plate 110 and an adhesive 114 are alternately stacked on the plate 112 to form a base-plate stack 120 (step 202, FIG. 3B). The number of laminated glass base plates 110 is a plurality (three or more), for example, about 10 to 100. Note that the adhesive 114 is not applied between the plate 112 and the first glass base plate 110.

  The adhesive 114 is a photocurable resin that is solidified by irradiation with ultraviolet rays having a predetermined wavelength. As the ultraviolet curable resin, a resin that can easily peel off the glass base plate 110 bonded by hot water, an organic solvent, or heat is preferable. The adhesive 114 may be applied by a dropping method or by a spray method.

  After a predetermined number of glass base plates 110 are stacked, the second plate 116 is placed on the stacked glass base plate 110 (step 204, FIG. 3C). The adhesive 114 is not applied between the uppermost glass base plate 110 and the second plate 116, but simply placed. The second plate 116 has the same composition and thickness as the first plate 112, that is, the same light transmittance and refractive index.

  While sandwiched between the two plates 112 and 116, ultraviolet light sources 118 are arranged on both upper and lower sides thereof. Then, the adhesive 114 is cured by irradiating light (ultraviolet rays) from a direction perpendicular to both main surfaces of the base plate laminate 120 (step 206, FIG. 3D). At this time, the light intensities of the light sources 118 on both sides are adjusted so as to reach the thickness center region of the base laminate with equal intensity from both main surfaces.

  According to the above configuration, since the light reaches from both sides of the base plate laminate 120 with the same intensity, the curing of the adhesive 114 can proceed from both sides of the base plate laminate 120 equally. Therefore, the residual stress due to the shrinkage of the adhesive 114 becomes even on the front and back, and the distortion of the base plate laminate 120 can be reduced. Accordingly, it is possible to reduce the dimensional error above and below the laminated block after the cutting process and the decrease in the verticality of the end faces of the glass substrates.

  In addition, since the second plate 116, which is the same as the base plate 112, is placed on the base plate laminate 120 instead of simply irradiating light from the upper and lower sides, the generation of strain can be further reduced. Can do. The second plate 116 has two roles. First, by irradiating light through the plates 112 and 116 both in the upper and lower directions, the integrated light amounts on both sides can be matched easily and reliably, and curing can proceed equally from both sides. Second, since the second plate 116 mechanically suppresses deformation due to its weight and rigidity, strain at the time of curing can be reduced.

Steps 210 to 216 are cutting processes.
The base plate laminate 120 cured as described above is taken out between the plates 112 and 116 and placed on the processing table 150 for vacuum suction (step 210, FIG. 4A). A large number of suction holes 152 are provided in the processing table 150, and vacuum suction is performed with the lower surface of the base plate laminate 120 being set at a negative pressure. The suction hole 152 is connected to an ejector type vacuum pump 154. Since the vacuum pump 154 is of an ejector type, it is possible to reduce the occurrence of a failure even when coolant enters during cutting.

  Then, suction is performed by the vacuum pump 154 to fix the base plate laminate 120 (step 212), and cutting is performed by the disc cutter 160 while supplying coolant (cutting fluid) to the cutting site (step 214, FIG. 4 (b)). )). Thereby, the base plate laminate 120 having a large area is divided into small portions, and a laminate block 130 having a small area is formed. When the suction by the vacuum pump 154 is stopped (step 216), the laminated block 130 can be easily picked up from the processing table 150 and recovered.

  The size of the laminated block 130 is slightly larger than the finally obtained glass substrate 100 (see FIG. 1). FIG. 4C shows a perspective view of the small piece laminated block 130 obtained by the cutting process. The laminated block 130 has a structure in which the glass substrate 100 and the adhesive 114 are alternately laminated.

  FIG. 5 is a diagram for explaining the processing table 150. In FIG. 5, the base-plate laminated body 120 is shown with the broken line. A groove 150 a is formed on the upper surface of the processing table 150 along the cutting line of the base plate laminate 120. Further, the groove 150 a is configured so that the blade of the disk cutter 160 (diamond disk) does not contact the processing table 150.

  The processing table is divided into a plurality of grooves 150a so as to correspond to the cutting area, and a plurality of suction holes 152 are provided per section. That is, the suction hole 152 is disposed inside the region partitioned by the groove 150a. Thereby, even when the base plate laminate 120 is cut and divided into the laminate blocks 130, the outside air is not sucked, and the cut base plate laminate 120 can be stably sucked.

  Here, the surface roughness (Ra) of the processing table 150 is 0.1 to 25 μm. By setting the surface roughness of the processing table 150 in the above range, it is possible to fix and cut the base plate laminate 120 on the processing table 150 very simply and reliably by simply placing it on the processing table 150 and sucking it. it can. If the processing table 150 is a mirror surface, the coolant enters and becomes slippery. If the processing table 150 is rougher than the above range, the degree of vacuum (suction force) decreases and the frictional force decreases. That is, if it is in said range, since a contact area can be reduced and a normal force can be raised, maintaining a vacuum degree, it becomes possible to fix easily and reliably. In addition, as for the surface roughness (Ra) of the said processing table, it is more preferable that it is 1-10 micrometers.

  Moreover, since it fixes by vacuum suction, unlike the case where it fixes to the process table 150 with an adhesive agent, it is not necessary to peel from the process table 150. FIG. Therefore, there is no possibility that the adhesion of the laminate itself is damaged by heat or a solvent, or the glass substrate in the lowermost layer of the laminate is damaged by peeling off with a spatula. Further, compared with the case of fixing using an ultraviolet curable tape and a vacuum adsorption method, the coolant does not enter and the frictional force does not decrease, so that there is no possibility that the dimensional accuracy is deteriorated due to deviation during cutting.

  Further, since the base plate laminate 120 is simply placed on the processing table 150, a process of attaching an adhesive or an ultraviolet curable tape is not necessary, and the material cost can be reduced. Therefore, the production cost can be greatly reduced.

  In the shape processing step (step 220), the outer shape of the laminated block 130 is cut and polished by machining using a grinder or the like along the outer shape (designed shape) of the cover glass. Also, voice input / output openings and button openings are formed by machining using a drill or the like.

  The peeling step (step 222) is a step of peeling the adhesive 114 of the laminated block 130 and separating the individual glass substrates 100. The peeling method in the peeling process depends on the characteristics of the protective material. For example, in the protective material made of an ultraviolet curable resin, there is a type of protective material that peels in an environment of warm water (80 to 90 degrees Celsius). . In such a case, the laminated block 130 can be peeled (separated) into each glass substrate 100 by immersing the laminated block 130 in a container containing warm water. In the case of peeling with a solvent, the glass substrate 100 can be peeled by immersing the laminated block 130 in a chemical solution layer of the solvent and swinging.

  In the chemical strengthening step (step 224), one or more alkali metals contained in the glass substrate 100 are ion-exchanged with the alkali metal of the molten salt to form a compressive stress layer on the surface layer portion of the glass substrate 100. To do. When the composition of the glass base plate 110 is an aluminosilicate glass as described above, the chemical strengthening treatment liquid is potassium nitrate or a mixed salt of potassium nitrate and sodium nitrate. Then, by immersing at a predetermined temperature (for example, 320 ° C. to 470 ° C.) for a predetermined time (for example, 3 to 600 minutes), Li + ions are replaced with Na + ions, and Na + ions are replaced with K + ions. Is given.

  The cleaning step (step 226) includes, for example, at least one of acid cleaning, alkali cleaning, rinse cleaning with pure water, and cleaning with IPA (isopropyl alcohol) performed in a state where the glass substrate 100 after chemical strengthening is placed on a pallet. Including.

[Other Embodiments]
FIG. 6 is a view for explaining another embodiment of the method for producing the glass substrate of the cover glass for electronic equipment according to the present invention. In the said embodiment, it demonstrated so that the plate 112 and the glass base plate 110 might be mounted horizontally and laminated | stacked in a lamination process. However, the present invention is not limited to the above example, and the base plate stack 120 is sandwiched between the two plates 112 and 116 in a state where the base plate stack 120 and the plates 112 and 116 are vertically arranged. You may laminate.

  Since the glass base plate 110 and the plates 112 and 116 are arranged upright as described above, the glass base plate 110 is dipped (immersed) in an adhesive tank as shown in FIG. An adhesive can be applied. The application of the adhesive by dipping can be automated (mechanized) more easily than the dropping type or the spraying type.

  In order to apply the adhesive 114 between the glass base plates 110 to be laminated, every other glass base plate 110 may be dipped. Further, since the glass base plate 110 and the plates 112 and 116 are not bonded, the glass base plates 110 at both ends are not dipped. By applying pressure with the two plates 112 and 116, the thickness of the adhesive can be made uniform.

  Then, as shown in FIG. 6B, ultraviolet light sources 118 are arranged on the left and right sides of the plate while pressure is applied by the two plates 112 and 116 on both sides. Then, the adhesive 114 is cured by irradiating light (ultraviolet rays) from a direction perpendicular to both main surfaces of the base plate laminate 120.

  In the present embodiment, the two plates 112 and 116 have a role of matching the integrated light amounts on both sides and a role of mechanically reducing strain at the time of curing by pressure and rigidity. Therefore, also by such a structure, the distortion of the base-plate laminated body 120 can be reduced suitably.

[Example]
Hereinafter, the present invention will be described with reference to examples and comparative examples. As the composition of the glass base plate (and glass substrate), 64.5 wt% SiO 2, 8.0 wt% Al 2 O 3, 0.4 wt% LiO 2, 16.0 wt% Na 2 O, 1. A glass material containing 0% by weight of ZrO2 was used.

  The large-sized glass base plate used for the test had a long side of 450 mm, a short side of 415 mm, and a thickness of 0.5 mm. A glass plate having a thickness of 20 mm and transmitting ultraviolet rays was used as the plate. A UV curable resin was used as a photocurable resin for bonding the glass base plates, and ultraviolet rays having a wavelength center of 360 nm (wavelength region 300 to 400 nm) were irradiated and cured at an intensity of 100 mW.

As Examples 1 and 2, in a state where the second plate was placed on the base plate laminate, it was cured by irradiation with ultraviolet rays from a direction perpendicular to both main surfaces of the base plate laminate. In Examples 1 and 2, the number of stacked layers was changed to 20 and 30 respectively. As Comparative Examples 1 and 2, the second plate was not placed on the base plate laminate, and was cured by irradiating ultraviolet rays only from above. In Comparative Examples 1 and 2, the number of stacked layers was different from 20 and 30, respectively. The results are shown in Table 1. Table 1 shows the flatness of the base plate laminate after curing and the result of the possibility of vacuum suction. Here, the flatness was measured with a three-dimensional measuring machine (manufactured by Mitutoyo, Coordinating measuring machine, model FJ805) according to JIS B 0621. In addition, “impossibility of vacuum suction” was determined based on whether or not a deviation occurred when cutting with a disk cutter.

  As can be seen from Table 1, in the comparative example cured by single-sided irradiation, vacuum adsorption was impossible, but in the example cured by double-sided irradiation, vacuum adsorption could be performed without any problem. Moreover, it turns out that an Example has a flatness of about 1/10 than a comparative example. Although the flatness decreases as the number of stacked layers increases, even when 30 sheets are cured by double-sided irradiation, the flatness of about 1/7 when 20 sheets are cured by single-sided irradiation is obtained. It can be understood why there is a clear difference in vacuum adsorption.

  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 above-described embodiment, it has been described that the two plates 112 and 116 are disposed on both sides of the base plate laminate 120 so that the light intensity and the integrated light amount are matched. However, the present invention is not limited to this, and only one plate 112 may be used by appropriately adjusting the output of the light source 118.

  The present invention relates to 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 a touch sensor such as a pointing device. It can utilize as a manufacturing method of the glass substrate of the cover glass for apparatuses.

DESCRIPTION OF SYMBOLS 100 ... Glass substrate, 102 ... Outer peripheral part, 104 ... Opening, 110 ... Glass base plate, 112 ... Plate, 114 ... Adhesive, 116 ... Plate, 118 ... Light source, 120 ... Base plate laminated body, 130 ... Laminated block, 150 ... Processing table, 150a ... Groove, 152 ... Suction hole, 154 ... Vacuum pump, 160 ... Disk cutter

Claims (3)

A laminating step of forming a base plate laminate in which a plurality of glass base plates are stacked and bonded;
In the manufacturing method of the glass substrate of the cover glass for electronic devices, including a cutting step of cutting the base plate laminate to form a laminated block having a small main surface area.
The adhesive that bonds the glass base plates together is a photocurable resin,
In the laminating step, light is applied to both the main surfaces so as to reach the central thickness region of the base plate laminate with an equal strength from a direction perpendicular to both main surfaces of the base plate laminate. The method for producing a glass substrate for a cover glass for electronic equipment, wherein the curing of the adhesive proceeds from both surfaces of the base laminate.   In the laminating step, the glass base plate and the adhesive are alternately arranged and laminated on the rigid plate that transmits light, and the plate having the same light transmittance as the plate is placed on the laminated glass base plate. 2. The method for producing a glass substrate of a cover glass for an electronic device according to claim 1, wherein the light is irradiated in a state of being covered. In the lamination step,
Two rigid plates that transmit light are arranged along both main surfaces of the base plate laminate,
In a state where the base plate laminate and the plate are arranged upright,
2. The method of manufacturing a glass substrate for a cover glass for an electronic device according to claim 1, wherein light is applied while applying pressure so that the base plate laminate is sandwiched between the two plates.

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