JP5926736B2 - Manufacturing method of cover glass for portable device - Google Patents

Description

  The present invention relates to the manufacture of a cover glass for a portable device used for a display screen of a portable device such as a mobile phone, a portable game machine, a PDA (Personal Digital Assistant), a digital still camera, a video camera, or a slate PC (Personal Computer). It is about the method.

Conventionally, in mobile devices such as a mobile phone, an acrylic resin plate having excellent transparency and light weight has been generally used for its display screen. As a result, cover glass made of glass materials that are superior in terms of surface smoothness, protective properties (weather resistance, antifouling properties), appearance and high quality compared to conventional acrylic resin plates are often used. It has become to.
Further, a pattern such as a character or figure such as a logo of a company name or a product name or a mark of an operation button is usually formed on the cover glass by a printing method.

JP 2006-27023 A

  Recently, instead of the conventional printing method, there has been a demand for a method of forming a pattern such as letters and figures directly on a cover glass. By directly engraving letters and figures on the cover glass, when the display screen of the mobile device is viewed from the front side, these letters and figures can be given a deep three-dimensional effect. It becomes possible to give a highly decorative decoration. In portable game machines and the like, it is also required that the user can recognize the operation buttons only by touching the fingertips.

  Patent Document 1 discloses that a first plate-like body that is substantially transparent in whole or in part, a groove formed on one surface of the first plate-like body, and a colorant in the groove. A first decorative part composed of a colored part colored and a second plate-like body which is joined to one surface side of the first plate-like body and is substantially transparent in whole or in part And a second decorative portion having a decoration on the surface opposite to the first plate-like body of the second plate-like body, and the first decorative portion and the second decorative portion are For example, there is disclosed a decorative article that can be visually recognized with at least a part overlapping when viewed from the other surface side of the first plate-like body. It also describes a watch using this decorative article as a cover glass, and using this decorative article as a cover member for a liquid crystal display portion of an electronic device such as a mobile phone, a pager, or a calculator.

  By the way, in recent years, touch-panel portable devices have become mainstream. In the touch panel method, the mobile device is operated mainly by pressing a predetermined part (for example, an icon displayed on the screen) of the display screen. Therefore, there is a demand for an improvement in the strength of the display screen. For this purpose, a cover glass having a sufficient strength even for a thin, lightweight, large screen (large area) is desired.

  The cover glass is subjected to a chemical strengthening treatment to improve its strength, but one of the factors that hinders the strength of the cover glass is a scratch. If the surface or end face of the cover glass is scratched, it grows and causes damage to the cover glass even with a relatively weak impact. For example, when a method of directly engraving patterns such as letters and figures is carried out by machining after chemically strengthening the cover glass, minute scratches and cracks are likely to occur, and the strength of the cover glass is significantly reduced. In some cases, the cover glass may break during machining. In particular, when engraving letters, graphics, or the like on the edge of the cover glass, or when the cover glass has a thin thickness of, for example, 1.5 mm or less, the above-described problem is likely to occur significantly.

  In the above-mentioned Patent Document 1, a groove is formed on one surface of a first plate-like body that is substantially transparent in whole or in part, and a colorant is placed in the groove to color the first. However, the decorative article of Patent Document 1 is based on the premise that the first plate-like body and the second plate-like body are joined to each other. The decorativeness is carried by superimposing the applied first decorative portion and the second decorative portion applied to the second plate-like body. Therefore, even if the configuration of such a decorative product is applied to, for example, a cover member of a mobile phone, the thin, light, and large screen (required for a cover glass used in a touch panel type portable device which is a mainstream in recent years) Even if it is a large area), the problem of having sufficient strength cannot be solved.

  The cover glass is usually produced by cutting (dividing into small pieces) a large plate glass formed into a sheet shape into a predetermined size (product size). The cover glass is manufactured through a number of processes including a cutting process into the product size. As the number of processes increases, it is expected that production costs will be affected, and the occurrence of scratches and the like due to conveyance between processes will increase. Therefore, a method for manufacturing a cover glass that is advantageous in terms of shortening the process as much as possible, cost, and suppressing the occurrence of scratches is desired.

  The present invention has been made to solve such a conventional problem, and its purpose is to provide a cover glass having a sufficient strength, having a concave portion that allows a user to recognize characters or figures, and thin. Suitable for cover glass with sufficient strength even for light weight and large screen (large area), or when using cover glass or glass material (glass substrate) that is chemically strengthened for touch panel type portable devices It is to provide a method for producing a high-quality cover glass that is advantageous in terms of cost, suppression of scratches, and the like.

As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by an invention having the following configuration.
That is, the present invention has the following configuration.

(Configuration 1)
The outer shape of the glass substrate for product-size cover glass is separated from the plate glass by an etching process using a resist as a mask, and a recess for allowing a user to recognize a character or a figure is formed on at least one main surface of the glass substrate. A method for manufacturing a cover glass for a portable device formed by etching using a resist as a mask, wherein the glass is disposed on one and other main surfaces of the plate glass so as to overlap in the thickness direction of the plate glass. A resist having an outer shape separation resist pattern for separating the outer shape of the substrate and a concave portion forming resist pattern disposed on at least one main surface of the plate-like glass to form the concave portion is provided on one and the other main sides. A cover device for portable devices, characterized by etching the plate-like glass formed on the surface. Scan is a method of manufacturing.

(Configuration 2)
It is a manufacturing method of the cover glass for portable devices of the structure 1 characterized by performing the external shape isolation | separation of the said plate glass, and formation of the said recessed part by the etching process of the same process.

(Configuration 3)
The resist formed on the plate-like glass is dissolved in an etchant so that the film thickness becomes thinner with the lapse of time of the etching process, and the concave portion forming resist pattern is a portion of the portion where the resist pattern is not formed. In the etching process, the melting start of the portion where the concave portion is formed in the sheet glass is delayed from the start of the melting of the outer shape separation portion in the sheet glass. It is a manufacturing method of the cover glass for portable devices of the structure 2 characterized by the above-mentioned.

(Configuration 4)
The recess-forming resist pattern is covered with an etchant-resistant film, and the glass sheet is etched with the resist pattern for outer shape separation to separate the glass substrate from the glass sheet, and then the etchant-resistant film is removed. And it is a manufacturing method of the cover glass for portable devices of the structure 1 which etches the said glass substrate with the said resist pattern for recessed part formation, and forms the said recessed part.

(Configuration 5)
The concave portion forming resist pattern is a pattern for forming the concave portion having a shape corresponding to a button region displayed on a screen of a display device of a portable device or an outline thereof on the glass substrate. It is a manufacturing method of the cover glass for portable devices in any one of 1-4.
(Configuration 6)
The cover glass for a portable device according to any one of configurations 1 to 5, wherein the plate glass is subjected to a chemical strengthening treatment and then an etching treatment is performed with the outer shape separation resist pattern and the recess formation resist pattern. It is a manufacturing method.

(Configuration 7)
The outer shape of the glass substrate for product-size cover glass is separated from the plate glass by blasting using a resist as a mask, and a recess for allowing the user to recognize characters or figures is formed on at least one main surface of the glass substrate. A method of manufacturing a cover glass for portable equipment formed by blasting using a resist as a mask, wherein the glass is disposed on one and other main surfaces of the plate glass so as to overlap in the thickness direction of the plate glass A resist having an outer shape separation resist pattern for separating the outer shape of the substrate and a concave portion forming resist pattern disposed on at least one main surface of the plate-like glass to form the concave portion is provided on one and the other main sides. Production of cover glass for portable devices characterized by blasting plate glass formed on the surface It is the law.
(Configuration 8)
The method for manufacturing a cover glass for a portable device according to any one of configurations 1 to 7, wherein the resist pattern for outer shape separation and the resist pattern for forming recesses are formed simultaneously.
(Configuration 9)
The depth of the said recessed part is 1/2 or less of the plate | board thickness of the cover glass for portable devices, The manufacturing method of the cover glass for portable devices in any one of the structures 1 thru | or 8 characterized by the above-mentioned.
(Configuration 10)
10. The cover glass for a portable device according to any one of configurations 1 to 9, wherein the remaining plate thickness excluding the depth (thickness in the depth direction) of the recess in the cover glass is 200 μm or more. Production method.

  According to the method for manufacturing a cover glass for portable devices of the present invention, a concave portion that allows a user to recognize characters or figures is formed on the surface, and the cover glass has a sufficient strength, is thin, lightweight, and has a large screen (large area). However, a cover glass having sufficient strength, or a cover glass suitable for a touch panel type portable device or a glass material (glass substrate) subjected to chemical strengthening treatment can be obtained, and a process can be obtained. Therefore, it is possible to provide a method for producing a high-quality cover glass that is advantageous in terms of cost and the like.

It is a whole perspective view which shows an example of the portable apparatus concerning this invention. It is a top view which shows the example of the external shape of the cover glass for portable devices which concerns on this invention. It is a top view which shows the example of the external shape of the cover glass for portable devices which concerns on this invention. It is a top view which shows the example of the external shape of the cover glass for portable devices which concerns on this invention. It is a top view which shows the example of the external shape of the cover glass for portable devices which concerns on this invention. It is a top view which shows the example which formed the recessed part which can be recognized as a character on the main surface of a cover glass. It is a figure which shows the example of the recessed part which can be recognized as a figure formed in the main surface of a cover glass. It is a figure which shows the example of the recessed part which can be recognized as a figure formed in the main surface of a cover glass. It is sectional drawing of the cover glass for portable devices which concerns on this invention. It is a figure which shows the preferable cross-sectional shape of a recessed part. It is sectional drawing which shows 1 process which concerns on 1st Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 1st Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 1st Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 1st Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 2nd Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 2nd Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 2nd Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 2nd Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 3rd Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 3rd Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is sectional drawing which shows 1 process which concerns on 3rd Embodiment of the manufacturing method of the cover glass for portable devices of this invention. It is a figure for demonstrating a strength test method. It is a figure for demonstrating a strength test method. It is a figure for demonstrating a strength test method. It is a figure for demonstrating another strength test method. It is a figure for demonstrating another strength test method.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall perspective view showing an example of a portable device according to the present invention.
FIG. 1 shows a case of a mobile phone 100 that performs an operation mainly on a touch panel as an example of a mobile device. The mobile phone 100 includes a casing 101 and a display screen 102 on the front surface side, and a cover glass is incorporated in the display screen 102.
More specifically, a cover glass is incorporated so as to protect the display screen, and the cover glass is disposed on the surface of the mobile phone 100.

  The cover glass is required to be strong because it is necessary to protect the display screen 102 from being damaged by an external impact. In particular, in the case of a touch panel, the mobile phone 100 is operated by pressing a predetermined part of the display screen 102 (for example, an icon displayed on the screen). Therefore, a cover glass with sufficient strength is required even if it is thin, lightweight, and has a large screen (large area).

2A to 2D are plan views showing examples of the outer shape of the cover glass for portable devices according to the present invention.
2A to 2D show examples in which the outer shape of the cover glass is a rectangular shape. FIG. 2A is a simple rectangular cover glass 1A, and FIGS. 2B and 2C are rounded at each corner. The rectangular cover glass 1B, 1C, and FIG. 2D show examples of the rectangular cover glass 1D in which each corner is rounded and a part thereof is cut out. The outer shape of the cover glass is derived from the shape, structure, etc. of the portable device in which it is incorporated, and the example shown in FIG. 2 is only an example. Of course, the cover glass of the present invention is not limited to the examples shown in FIGS. 2A to 2D. Further, for example, a cover crow according to the present invention includes a hole formed on the surface of glass such as a receiver hole.

  In the cover glass for portable devices according to the present invention, a recess for allowing a user to recognize a character or a figure is formed on at least one of the opposing main surfaces. A concave portion that allows a user to recognize a character or a figure is a concave portion that can be recognized as a character or a graphic when viewed from the front side of the portable device, or can be recognized when touched from the front side of the portable device, for example. . These characters or figures are patterns such as logos of company names and product names, marks of operation buttons, and the like.

FIG. 3 is a plan view showing an example in which concave portions that can be recognized as characters are formed on the main surface of the cover glass. FIGS. 4A and 4B are concave portions that can be recognized as figures formed on the main surface of the cover glass, respectively. It is a figure which shows the example of.
In FIG. 3, a concave portion that can be recognized as, for example, the letters “ABC” when viewed from the front side is formed on the main surface on the back side of the cover glass 1 (the back side in FIG. 3). Not only characters but also a figure such as a quadrangle as shown in FIG. 4A or a triangle as shown in FIG.

  Instead of the conventional printing method, by forming a concave part that engraves a pattern of characters, figures, etc. on the cover glass, when the display screen of a mobile device is viewed from the front side, the patterns of letters, figures, etc. A certain three-dimensional feeling can be given and it becomes possible to give decoration with high designability. Further, even if such a recess is not visually confirmed, it is possible to recognize the type of operation button (operation key), that is, what operation button, only by touching with a fingertip. For example, in a portable game machine, the user looks only at the screen during the game and hardly sees the operation buttons. Therefore, it is preferable to apply to the operation buttons of such a portable game machine. In addition, the cover glass which concerns on this invention includes the thing by which the recessed part was formed and the surface was printed.

FIG. 5 is a cross-sectional view of the cover glass according to the present invention.
In the cover glass of the embodiment shown in FIG. 5, the concave portion 2 that can be recognized as a character or a graphic when viewed from the front side of the portable device or that can be recognized when touched from the front side of the portable device is formed on the cover glass 1. It is formed on both surfaces of the opposing main surfaces 11 and 12 respectively. Needless to say, the concave portion intended to be recognized mainly when touched from the front side of the portable device is either one of the opposing main surfaces 11 and 12 of the cover glass 1, in other words, It is formed on the front surface when mounted on a portable device.
In short, the concave portion formed on the surface of the cover glass on the front side of the portable device can be visually or tactilely recognized, and the concave portion formed on the surface of the cover glass opposite to the above can be visually recognized.

  Here, the recessed part 2 is demonstrated in detail with reference to FIG. In the present invention, the cross-sectional shape of the concave portion 2 is more preferably, for example, as shown in FIG. 6, when the cover glass 1 is viewed in cross section, the main surface flat portion of the cover glass 1 and the inner surface of the concave portion 2. It is desirable that the edge 2b at the boundary with the (wall surface) 2a has a rounded shape. In the case of a portable device to which the present invention is applied, each operation button in the touch panel region is often smaller than the fingertip touched by the user, and the fingertip presses not only the inner surface 2a of the recess but also the edge portion 2b. Load. As described above, since the edge portion 2b has a rounded shape, the stress concentration when the load due to repeated pressing is also applied to the edge portion 2b can be reduced, so that the mechanical strength of the recess 2 is reduced. Can be suppressed. Further, since the edge portion 2b is rounded, the fingertip does not hurt even if the concave portion 2 is repeatedly pressed with the fingertip.

  In addition, as shown in FIG. 6, in the present invention, when the cover glass 1 is viewed in cross section, the boundary between the bottom surface of the recess 2 and the inner surface 2a that is the wall surface is more rounded. preferable. Furthermore, it is more preferable that the entire bottom surface has a rounded shape. In other words, it is more preferable that when the cover glass 1 is viewed in cross section, no sharp corner is formed at the recess itself and the boundary between the recess and the main surface flat portion. By setting it as said structure, when the user of the portable apparatus 100 presses a recessed part, since it does not raise | generate stress concentration, it can prevent further that the cover glass 1 is damaged.

Next, the manufacturing method of the said cover glass by this invention is demonstrated.
[First Embodiment]
7A to 7D are cross-sectional views sequentially showing steps according to the first embodiment of the method for manufacturing a cover glass for a portable device of the present invention.
The cover glass for portable devices according to the present invention is produced by cutting (dividing into small pieces) a large plate-shaped plate glass formed into a sheet shape into a predetermined size (product size).

  First, a resist (photosensitive organic material, particularly photosensitive resin material) 3 is applied and formed on both the front and back main surfaces of the sheet glass 10 manufactured by the downdraw method, the float method, or the like (see FIG. 7A). The resist 3 having the resist pattern 3b for outer shape separation and the resist pattern 3a for forming recesses as shown in FIG. 7B is formed. The resist pattern 3b for outer shape separation is formed on both main surfaces of the plate glass 10, and the resist pattern 3b on one main surface and the resist pattern 3b on the other main surface are the thickness of the plate glass 10. It arrange | positions so that it may overlap in the direction (facing). In this embodiment, the recess-forming resist pattern 3a is formed on both main surfaces of the glass sheet 10, but is formed on one main surface and the other main surface. Each resist pattern 3 a is disposed at a position where the concave portion does not overlap in the thickness direction of the sheet glass 10. The concave portion forming resist pattern 3a is a pattern for forming the concave portion having a shape corresponding to the button region displayed on the screen of the display device of the portable device or the contour thereof on the glass substrate.

  In the present embodiment, a resist pattern having a polymerization degree gradient in the thickness direction is formed on both main surfaces of the sheet glass 10 so that the main surface side has the smallest degree of polymerization. In order to make the edge portion 2b at the boundary between the main surface flat portion of the glass substrate and the inner surface 2a of the concave portion 2 as shown in FIG. 6 rounded, for example, the following method is suitable. is there.

  That is, a resist pattern having a polymerization degree gradient in the thickness direction is formed on the main surface of the sheet glass 10 so that the degree of polymerization becomes the smallest on the main surface side, and wet etching is performed using the resist having this resist pattern as a mask. Do. Thus, in order to have a polymerization degree gradient in the thickness direction in the resist pattern, it is necessary to weaken the adhesion between the glass (main surface) and the resist when forming the resist pattern. In order to weaken the adhesion between the glass and the resist, for example, the resist thickness, exposure amount, post-bake conditions, and the like are controlled. Control of these conditions is performed by appropriately changing the type of resist used and the energy of exposure light. By controlling the adhesion between the glass and the resist in this way, the etching solution can easily enter the interface between the resist and the glass (main surface), and as a result, the edge portion 2b is rounded. It is formed in a shape with In the present embodiment, not only the recesses but also the cut portions (separation portions) where the outer shape separation resist pattern 3b is formed have a rounded edge at the boundary with the glass main surface flat portion. . Since the edge part of the end surface of the produced cover glass is rounded, it is possible to prevent injuries or the like when the operator's finger contacts, for example.

  Then, the glass sheet 10 on which the resist 3 having the resist pattern 3b for outer shape separation and the resist pattern 3a for forming recesses is formed on one and the other main surfaces is etched. That is, wet etching is performed using an etching solution (for example, an acidic solution containing hydrofluoric acid) that can dissolve a glass material, using the resist 3 having the resist pattern 3b for outer shape separation and the resist pattern 3a for forming a recess as a mask. Thus, in the cutting part 4, the glass substrate 1 having a predetermined product size is separated from the plate glass 10 by penetrating from the front and back of the plate glass 10. At the same time, predetermined recesses 2 are formed on both main surfaces of the separated glass substrate 1 (see FIG. 7C). In this case, the etching processing time is adjusted to a time sufficient for the front and back of the sheet glass to penetrate at the cut portion.

Examples of the acidic solution containing hydrofluoric acid include a hydrofluoric acid aqueous solution, a mixed solution of hydrofluoric acid and hydrochloric acid, a mixed solution of hydrofluoric acid and sulfuric acid, and an aqueous solution containing ammonium fluoride. Since wet etching is isotropic etching (etching proceeds not only in the vertical direction but also in the left-right direction), the bottom corner of the recess 2 is finished in a rounded shape. For this reason, since stress distribution can be aimed at, it is more preferable to form a recessed part by wet etching. Note that the recess may be formed by dry etching.
Then, the remaining resist pattern is peeled off from the glass substrate, and the glass substrate is washed (see FIG. 7D).

Thus, the cover glass according to the present embodiment is completed.
As shown in FIG. 7D, the concave portion 2 and the outer peripheral end face 13 of the obtained cover glass are both formed in a shape with rounded edges. As described above, a resist pattern having a polymerization degree gradient in the thickness direction is formed so that the main surface side of the sheet glass has the smallest degree of polymerization, and the adhesion between the glass main surface and the resist becomes weak, and etching is performed. Sometimes the edges are considered rounded.

  In the cover glass obtained by the present embodiment, the surface 2a of the recess 2 is an etched surface processed by etching. According to the inventor's study, when the surface 2a of the recess 2 is an etching surface, it is possible to suppress the occurrence of minute scratches, cracks, etc. during the etching process, so that the strength of the cover glass is not impaired. For example, it was found that the high strength of the cover glass obtained by the chemical strengthening treatment can be maintained. In particular, when the concave portion is formed in the cover glass and the concave portion is pressed, the distortion of the cover glass becomes larger than that in the case where the concave portion is not formed, and as a result, the stress acting on the surface 2a of the concave portion is increased. Since it increases, it becomes easy to receive the influence of the fine crack, crack, etc. of the surface 2a of a recessed part. Therefore, when forming a recessed part in the main surface of a cover glass like this invention, it is preferable that the surface 2a of a recessed part is an etching surface formed by the etching process.

  In the present embodiment, the end surface 13 of the cover glass is also an etching surface. Since the end face of the cover glass thus produced is an etched face, the occurrence of minute scratches and cracks on the end face of the cover glass can be suppressed, and the strength reduction of the cover glass due to these scratches and cracks can be prevented. .

  As described above, according to the method for manufacturing a cover glass for portable devices of the present embodiment, a cover glass having a sufficient strength is formed, with a concave portion that allows a user to recognize characters or figures, and is thin and lightweight. Even for a large screen (large area), a cover glass having sufficient strength or a cover glass suitable for a touch panel type portable device can be obtained. In addition, as described above, a resist pattern for outer shape separation and a resist pattern for forming a recess are simultaneously formed (at a time) in the resist layer on the main surface of the plate glass, and the plate is etched by the same process using this resist as a mask. Since the outer shape separation and the recess formation of the glassy glass are performed simultaneously (at the same time), for example, compared with the case where the outer shape separation and the recess formation of the sheet glass are performed in separate steps, the positioning of the recess and the outer shape is not required, and the positional dimensional accuracy The manufacturing process can be greatly shortened. Therefore, it is possible to produce a high-quality cover glass that is advantageous in terms of cost, suppression of scratches, and the like.

  In this embodiment, the case where the concave portions are formed on both main surfaces of the glass substrate has been described. However, when the concave portion is formed only on one of the main surfaces of the glass substrate, the main portion that forms the concave portion is described. The concave portion forming resist pattern may be formed only on the resist on the surface side.

[Second Embodiment]
In the above-described first embodiment, the etching processing time is regulated by the processing time required for the outer shape separation of the plate glass, so that the digging depth of the recesses 2 etched at the same time is inevitably the same as that of the plate glass. The depth corresponds to approximately 1/2 of the plate thickness. In this Embodiment, the depth of the said recessed part 2 formed in a glass substrate main surface is controllable.
8A to 8D are cross-sectional views sequentially showing steps according to the second embodiment of the method for manufacturing the cover glass for portable devices of the present invention.

  In the same manner as in the first embodiment, a resist 3 having a resist pattern 3b for outer shape separation and a resist pattern 3a for forming recesses is formed on one and the other main surfaces of the sheet glass 10. Then, the recess forming resist pattern 3a (all) is covered with an etchant resistant film 5 (see FIG. 8A). As the etchant resistant film 5, a material having resistance to at least an etching process applied to the outer shape separation of the sheet glass is used. For example, a polyimide resin having resistance to the acidic solution containing hydrofluoric acid used in the first embodiment, an adhesive resin film such as polyester (PET), or a protective film made of oil such as wax is preferably used. Can do.

Next, in a state where the recess forming resist pattern 3a is covered with the etchant resistant film 5, the plate glass 10 is etched with the outer shape separation resist pattern 3b to separate the glass substrate from the plate glass 10 (FIG. 8B).
Thereafter, the etchant resistant film 5 is removed, and the glass substrate separated by the recess forming resist pattern 3a is etched to form the recess 2 (see FIG. 8C).
Then, the remaining resist pattern is peeled off, and the glass substrate is washed (see FIG. 8D).

Thus, the cover glass according to the present embodiment is completed.
In this embodiment, since the etching process for the outer shape separation of the sheet glass and the etching process for the recess formation are performed in different steps, the etching time for forming the recesses is not regulated by the processing time required for the outer shape separation of the sheet glass. . Therefore, the depth of the concave portion 2 formed on the glass substrate main surface can be arbitrarily controlled by appropriately changing the etching processing time. 8A to 8D show a case where the depth of the concave portion 2 is controlled to a depth shallower than the depth corresponding to about 1/2 of the plate thickness of the plate glass.

[Third Embodiment]
Also in the present embodiment, the depth of the concave portion 2 formed on the glass substrate main surface can be controlled.
9A to 9C are cross-sectional views sequentially illustrating steps according to the third embodiment of the method for manufacturing a cover glass for a portable device of the present invention.

  In substantially the same manner as in the first embodiment, a resist 3 having a resist pattern 3b for outer shape separation and a resist pattern 3a for forming recesses is formed on one and the other main surfaces of the sheet glass 10. However, in the present embodiment, the resist 3 is dissolved in an etchant so that the film thickness becomes thinner with the lapse of time of the etching process, and the recess forming resist pattern 3a is not formed with the resist pattern. It is formed by a resist thinner than the film thickness of the partial resist 3 (see FIG. 9A). In order to form such a resist pattern for forming recesses, for example, the resist 3 is exposed with a halftone mask having a semi-transparent film (semi-transmitting part) whose exposure light transmittance is adjusted to a predetermined value to form recesses. At the location, the exposure time is adjusted so that the resist remains in a thin film by the development process after exposure.

Then, by performing wet etching using the resist 3 having the resist pattern 3b for outer shape separation and the resist pattern 3a for forming the recesses as a mask, the cut portion 4 is penetrated from the front and back of the plate glass 10, and is predetermined from the plate glass 10. The glass substrate 1 of the product size is separated, and at the same time, predetermined recesses 2 are formed on both main surfaces of the separated glass substrate 1 (see FIG. 9B).
Then, the remaining resist pattern is peeled off and the glass substrate is washed (see FIG. 9C).

Thus, the cover glass according to the present embodiment is completed.
In the present embodiment, as in the first embodiment, the outer shape separation resist pattern and the concave portion formation resist pattern are formed simultaneously (at a time), and the outer shape of the sheet glass is formed by etching in the same process using this resist as a mask. Separation and recess formation are performed at the same time (at the same time). However, in the etching process, since the recess forming resist pattern 3a is dissolved and removed by the etching process, the etching of the glass is started. The melting start time of the portion where the concave portion is formed in the glass sheet is later than the melting start time of the outer shape separation portion of the plate glass. Therefore, control is performed so that the concave portion has a predetermined depth (for example, a depth shallower than a depth corresponding to approximately 1/2 of the plate thickness of the plate glass) at the end of the outer shape separation process in the plate glass. Can do.

  In the first to third embodiments described above, the outer shape separation and the recess formation of the plate glass are performed by the etching process using the resist having the resist pattern for outer shape separation and the resist pattern for recess formation as a mask. However, the present invention is not limited to this. For example, the outer shape of the glass sheet may be separated and the recesses may be formed by machining with sand blast using the same resist as the mask.

  That is, the present invention separates the outer shape of the glass substrate for product-size cover glass from the plate glass by blasting using a resist as a mask, and has a recess for allowing a user to recognize characters or figures of the glass substrate. A method for manufacturing a cover glass for a portable device, which is formed by blasting using a resist as a mask on at least one main surface, wherein one and the other main glass plates are overlapped in the thickness direction of the plate glass. A resist having an outer shape separation resist pattern for separating the outer shape of the glass substrate disposed on the surface, and a concave portion forming resist pattern for forming the concave portion disposed on at least one main surface of the plate glass. Blasting the sheet glass formed on one and the other main surfaces There is provided also a method for manufacturing the dexterity cover glass. This invention also makes it possible to greatly shorten the manufacturing process, and to manufacture a high-quality cover glass that is advantageous in terms of cost.

  The cover glass obtained by the present invention is particularly suitable in a form in which, for example, the main surfaces 11 and 12 of the cover glass 1 have a region corresponding to the touch panel, and at least one of the concave portions 2 exists in the region corresponding to the touch panel. is there.

Further, according to the present invention, it is possible to provide a cover glass having sufficient strength even if it is thin, lightweight, and has a large screen (large area). In the present invention, the total thickness of the cover glass can be reduced to, for example, 0.3 mm to 1.5 mm. In the present invention, the cover glass has an outer shape of, for example, a rectangular shape, and its main surface can have a large area of, for example, 30 cm 2 or more.
In addition, according to the present invention, it is possible to provide a cover glass suitably for a touch panel type portable device that is particularly required to have a high strength display screen.

  The thickness (plate thickness) of the cover glass of the present invention is preferably in the range of, for example, about 0.3 mm to 1.5 mm, more preferably from the viewpoint of meeting the market needs for recent thinning and weight reduction of portable devices. Is in the range of about 0.4 mm to 0.8 mm.

  In the present invention, the glass constituting the cover glass is preferably an amorphous aluminosilicate glass. A glass substrate made of such an aluminosilicate glass is excellent in strength after chemical strengthening. As such an aluminosilicate glass, an aluminosilicate glass containing SiO2 as a main component is 58 to 75% by weight, Al2O3 is 0 to 20% by weight, Li2O is 0 to 10% by weight, and Na2O is 4 to 20% by weight. Can be used.

In the cover glass according to the present invention, it is preferable to perform a chemical strengthening treatment on the cover glass in order to improve the strength.
As a method of chemical strengthening treatment, for example, a low temperature ion exchange method in which ion exchange is performed in a temperature range that does not exceed the temperature of the glass transition point, for example, a temperature of 300 ° C. to 500 ° C. is preferable. The chemical strengthening treatment is a process in which a molten chemical strengthening salt is brought into contact with a glass substrate, whereby an alkali metal element having a relatively large atomic radius in the chemical strengthening salt and a relatively small atomic radius in the glass substrate. This is a treatment in which an alkali metal element is ion-exchanged, an alkali metal element having a large ion radius is permeated into the surface layer of the glass substrate, and compressive stress is generated on the surface of the glass substrate. As the chemical strengthening salt, nitrates of alkali metals such as potassium nitrate and sodium nitrate can be preferably used. The cover glass that has been chemically strengthened is improved in strength and excellent in impact resistance, and is therefore suitable for a cover glass used for a portable device that requires impact and pressure and requires high strength. In particular, in the present invention, the chemical strengthening treatment is effective because the high strength obtained by the chemical strengthening treatment can be ensured even if the concave portion is formed on the main surface of the cover glass.

  In the present invention, after the sheet glass is chemically strengthened, the outer shape separation resist pattern and the recess formation resist pattern may be etched, or the outer shape separation resist pattern and the After performing the etching process using the resist pattern for forming recesses, the obtained glass substrate may be subjected to a chemical strengthening process.

  From the viewpoint of the dimensions of the formed recesses, it is preferable to perform an etching process such as recess formation after the chemical strengthening treatment because the dimensions of the recesses do not change. On the other hand, from the viewpoint of securing the strength of the cover glass, it is preferable to perform a chemical strengthening treatment after the etching treatment. The reason is that there is an internal tensile stress layer corresponding to the surface compressive stress layer inside the chemically strengthened glass substrate, and this internal tensile stress is a factor that destroys the glass substrate when external force acts on the glass substrate. It becomes. Therefore, the etching treatment such as the formation of the recesses is desirably performed after chemical strengthening from the viewpoint of dimensional accuracy, while it is preferably performed before chemical strengthening from the viewpoint of strength.

In the present invention, the remaining plate thickness excluding the depth (thickness in the depth direction) of the recess in the cover glass is preferably at least 3 times the thickness of the compressive stress layer of the recess due to chemical strengthening. 4 times or more is more preferable. If it is less than 3 times the thickness of the compressive stress layer, the strength required for the cover glass may not be obtained.
The depth of the concave portion is determined by a Z-axis (depth direction) measuring machine (for example, a non-contact Z-axis measuring machine manufactured by Nissho Precision Optical Co., Ltd. “micron depth height measuring machine: KY-90-HL-”). TV "or a measuring microscope" MM-400 "manufactured by Nikon Corporation). In addition, the compressive stress value of the main surface flat portion and the concave portion and the depth (thickness) of the compressive stress layer are determined by a Babinet method using a stress meter (for example, a precision strain meter “BSP-3” manufactured by Orihara Seisakusho Co., Ltd.). It is preferable to measure. However, if it is difficult to measure by the Babinet method depending on the glass composition and the type of chemically strengthened salt, the compressive stress value or compressive stress can be measured by the wave guide method using the surface stress meter “FSM-6000” manufactured by Orihara Seisakusho, for example. It is also possible to measure the depth of the layer.

  Moreover, in this invention, it is preferable that the remaining plate | board thickness except the depth (thickness of a depth direction) of the said recessed part in a cover glass is 200 micrometers or more. If the remaining plate thickness is less than 200 μm, the strength required for the cover glass may not be obtained. In addition, when the recessed part is each formed in both the main surfaces of a cover glass, it is preferable that the remainder which subtracted the sum of the largest depth of each main surface from board thickness is 200 micrometers or more. In addition, when there are a plurality of recesses having different depths on one or both main surfaces, the remainder obtained by subtracting the maximum depth of each main surface from the plate thickness is preferably 200 μm or more.

  Further, the size (width) of the concave portion of the cover glass is preferably such a size (width) that the finger and the bottom of the concave portion do not contact when the cover glass is touched with a finger.

  In addition, the remaining plate thickness excluding the depth of the concave portion is the same, but when comparing the mechanical strength of the cover glasses having different total plate thicknesses (for example, the strength by the strength test method in the examples described later), The greater the plate thickness, the greater the strength. Moreover, when comparing the cover glasses having the same ratio of the total plate thickness and the remaining plate thickness, the larger the total plate thickness, the greater the strength.

  As described above, according to the present invention, there is provided a cover glass suitable for a touch-sensitive portable device that has a sufficient strength even when it is thin, lightweight, and has a large screen (large area), and particularly requires a high strength. Can be provided.

Hereinafter, the present invention will be described in more detail with reference to specific examples. In addition, this invention is not limited to a following example.
(Example)
The cover glass of this example was manufactured through the following (1) plate-like glass cutting and recess forming step, and (2) chemical strengthening step.

(1) Sheet Glass Cutting Process and Recess Forming Process First, a sheet glass having a thickness of 0.5 mm made of an aluminosilicate glass manufactured by a downdraw method or a float method is cut to a predetermined size (10 cm × A glass substrate for cover glass of 5 cm) was produced. That is, the outer shape of the glass substrate for cover glass of product size was separated from the plate glass. Moreover, the recessed part was formed in this glass substrate. As this aluminosilicate glass, SiO2: 62.5 to 64.5 wt%, Al2O3: 13 to 15 wt%, Li2O: 5 to 7 wt%, Na2O: 9.5 to 11.5 wt%, ZrO2: 5 A chemically strengthened glass containing ˜7% by weight was used.

  In this example, the cutting processing and the recess formation of the plate glass were performed by an etching process using a resist as a mask. That is, a resist (photosensitive organic material) having etching resistance is applied to both surfaces of the plate-like glass, and predetermined exposure and development are performed to form a resist pattern and a recess for outer shape separation as shown in FIG. 7B. A resist having a resist pattern was formed. The resist pattern for outer shape separation is formed on both main surfaces of the sheet glass and is arranged so as to overlap in the thickness direction of the sheet glass. Further, in this embodiment, the concave portion forming resist pattern is formed on both main surfaces of the sheet glass, but the concave portion formed on one main surface and the concave portion formed on the other main surface are plate-like. It is arranged at a position that does not overlap in the thickness direction of the glass. In addition, a resist having a polymerization degree gradient in the thickness direction was formed on both the main surfaces of the plate glass so that the main surface side had the smallest degree of polymerization.

Then, using the resist having the resist pattern for outer shape separation and the resist pattern for forming recesses as a mask, cutting is performed by wet etching using an etching solution (for example, an acidic solution containing hydrofluoric acid) that can dissolve the glass material. The glass substrate having a predetermined product size was separated from the plate glass by penetrating from the front and back of the plate glass. Further, in the same wet etching process, predetermined recesses were formed on both main surfaces of the separated glass substrates. In this example, in order to correspond to a static pressure strength test method described later, a concave portion that can be recognized as a cross shape as shown in FIG. 10C when formed from the front side (plan view) was formed. The etching treatment time was adjusted to a time sufficient for the front and back of the sheet glass to penetrate at the above-mentioned cut portion.
Thereafter, the remaining resist was peeled off from the glass substrate, and the glass substrate was washed.

(2) Chemical strengthening process Next, the glass substrate which separated from said plate-shaped glass and finished the recessed part formation was chemically strengthened. Chemical strengthening prepared the chemical strengthening liquid which mixed potassium nitrate and sodium nitrate, heated this chemical strengthening solution to 360 degreeC, and immersed the said cover glass for about 3 hours, and performed the chemical strengthening process. The cover glass that had been chemically strengthened was sequentially immersed in each of washing tanks of sulfuric acid, neutral detergent, pure water, pure water, IPA, and IPA (steam drying), ultrasonically cleaned, and dried.

Thus, the cover glass of this example was completed.
The concave part and the outer peripheral end face of the obtained cover glass were both formed in a shape with rounded edges. As described above, a resist pattern having a polymerization degree gradient in the thickness direction is formed so that the main surface side of the sheet glass has the smallest degree of polymerization, and the adhesion between the glass main surface and the resist becomes weak, and etching is performed. Sometimes the edges are considered rounded. In addition, the shape of a recessed part and an outer peripheral end surface cut | disconnected the location, and confirmed cross-sectional shape by microscope observation.

Next, the static pressure strength of the obtained cover glass was measured. Specifically, an area in which a concave portion of a cross shape (in plan view) of the cover glass is formed on the ring-shaped stainless steel receiving jig 21 having an outer diameter of 40 mm and an inner diameter of 30 mm shown in FIG. The cover glass 1 to be measured is placed so that the tool 21 surrounds from below, and the concave portion of the cover glass 1 is pressed from above by a 10 mmφ steel flat head 22 with a load of 200 N for 2 seconds (see FIG. 10B). ). An elastic material having a rubber hardness of 50 (JIS K6253) having a thickness of 1 mm is attached to the tip of the flat head 22. The number of measurement is 30 cover glasses.
As a result of the measurement, the cover glass of the above Example was not damaged.

  The impact strength of the cover glass was measured by dropping the ball. The test method in this case is a drop test in which the ball 31 is dropped from above the sample 1 (cover glass) placed on the holder 30 as shown in FIG. 11 (see FIG. 11A). In addition, the cover glass of the sample is installed in the penetration part of the holder 30, and the width of 2 mm of the cover glass edge is held by the holder (see FIG. 11B). The falling position of the ball is a concave portion forming portion of the cover glass. Here, the ball is a sphere having a weight of 32 g and a diameter of 20 mm, and the material is SUS304. The material of the holder is SUS304.

The strength was evaluated based on the presence or absence of breakage by changing the distance (hereinafter referred to as height) between the ball drop start portion and the cover glass (see FIG. 11A). Ten cover glasses were measured at each height.
As a result of the measurement, the cover glass of the above example was broken at a height of 800 mm with zero breakage and at a height of 900 mm, one piece was broken.
Next, the change in strength when the depth of the recess was changed was examined. Specifically, based on Embodiment 2 and the above example, a glass cover having a thickness of 0.5 mm was used, and a cover glass in which concave portions having different depths were formed on the glass substrate was prepared. At this time, a cover glass in which the thickness when the depth of the concave portion was subtracted from the plate thickness was changed between 100 μm and 400 μm every 50 μm was created. And the said drop test was done. As a result, the thickness when the depth of the concave portion was subtracted from the plate thickness was 200 μm or more, and the rate of occurrence of breakage was remarkably smaller than that of less than 200 μm.

In this embodiment, the cover glass was manufactured according to the process shown in FIG. 7 described above. However, the present invention is not limited to this. For example, when the depth of the recess is controlled, the above-described FIGS. Or a cover glass can be produced according to the process shown to FIG. 9A-FIG. 9C.
In this embodiment, the separation of the outer shape of the glass sheet and the formation of the recesses were performed by etching using a resist as a mask. However, the present invention is not limited to this, and sandblasting using the same resist as a mask may be performed by machining. Good.

Claims (7)

The outer shape of the glass substrate for product-size cover glass is separated from the plate glass by an etching process using a resist as a mask, and a recess for allowing a user to recognize a character or a figure is formed on at least one main surface of the glass substrate. A method for manufacturing a cover glass for a portable device formed by an etching process using a resist as a mask,
At least one of the plate-like glass and a resist pattern for outer shape separation arranged on one and the other main surfaces of the plate-like glass so as to overlap in the thickness direction of the plate-like glass and separating the outer shape of the glass substrate resist having a recess forming a resist pattern for forming the recesses are arranged on the main surface of the outer separation of said plate glass by etching process of the same process on the plate-like glass formed on the main surface of the The concave portion is formed, and the concave portion forming resist pattern is formed by a relatively thin resist dissolved in an etchant,
In the etching process, the method for producing a cover glass for a portable device is characterized in that the start of melting of the portion where the concave portion is formed in the plate glass is delayed from the start of melting of the outer shape separation portion in the plate glass. . The outer shape of the glass substrate for product-size cover glass is separated from the plate glass by an etching process using a resist as a mask, and a recess for allowing a user to recognize a character or a figure is formed on at least one main surface of the glass substrate. A method for manufacturing a cover glass for a portable device formed by an etching process using a resist as a mask,
At least one of the plate-like glass and a resist pattern for outer shape separation arranged on one and the other main surfaces of the plate-like glass so as to overlap in the thickness direction of the plate-like glass and separating the outer shape of the glass substrate The recess-forming resist pattern is covered with an etchant-resistant film on the plate-like glass on which the resist having a recess-forming resist pattern for forming the recess is disposed on the main surface of the plate-like glass . The glass sheet is separated from the glass sheet by etching the glass sheet with a resist pattern for outer shape separation, and then the etchant-resistant film is removed, and the glass substrate is formed with the resist pattern for forming recesses. The manufacturing method of the cover glass for portable devices characterized by forming the said recessed part by an etching process. The concave portion forming resist pattern is a pattern for forming, on the glass substrate, the concave portion having a shape corresponding to a button region displayed on a screen of a display device of a portable device or an outline thereof. Item 3. A method for producing a cover glass for a portable device according to Item 1 or 2 . The cover glass for a portable device according to any one of claims 1 to 3 , wherein the plate glass is subjected to a chemical strengthening treatment and then subjected to an etching treatment with the resist pattern for outer shape separation and the resist pattern for forming a recess. Manufacturing method. The manufacturing method of the cover glass for portable devices in any one of Claims 1 thru | or 4 which forms the said resist pattern for external shape separation, and the resist pattern for recessed part formation simultaneously with respect to the main surface of the said sheet glass . The depth of the said recessed part is 1/2 or less of the plate | board thickness of the cover glass for portable devices, The manufacturing method of the cover glass for portable devices in any one of the Claims 1 thru | or 5 characterized by the above-mentioned. The cover glass for portable devices according to any one of claims 1 to 6 , wherein a remaining plate thickness excluding a depth (thickness in a depth direction) of the concave portion in the cover glass is 200 µm or more. Manufacturing method.

Images