Method of manufacturing cover glass, cover glass and cover glass-equipped display device

The objective is to provide a cover glass having edge surfaces and a through-hole, formed with high external dimensional precision. The cover glass has a unit substrate comprising glass, and a resinforced portion containing a resin material provided on the edge surfaces of the unit substrate.

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to a cover glass which is provided on an observer side of a display device, and a method of manufacturing the same. In addition, the present invention relates to the display device provided with the cover glass.

Background Art

Conventionally, a technique has been known in which a cover glass for protection of a display surface of a display device is provided on an observer side of the display device such as a liquid crystal display or an organic EL display. In a case in which the display device is equipped with a touch panel function, the cover glass also serves a role of protecting the display device and a touch panel sensor which is provided on the observer side of the display device. Incidentally, another technique has been also known in which a cover glass and a touch panel sensor are integrally configured.

Recently, portable terminals equipped with display devices have been remarkably popular such as a smart phone and a tablet PC. The portable terminal is required to have durability with respect to a drop impact generated in the use environment. Accordingly, there is a demand for high strength in a cover glass that protects the display device to be capable of withstanding the impact frequently generated. Under such circumstances, Patent Document 1, for example, proposes a method of configuring a cover glass using a tempered glass which includes a compressive stress layer on which a compressive stress is generated being formed on a surface thereof.

In Patent Document 1, the cover glasses having dimensions corresponding to respective dimensions of individual display devices are produced by dividing the large tempered glass into individual pieces. Meanwhile, the compressive stress layer of the tempered glass is formed on the glass surface by chemical treatment, or heat treatment. Accordingly, a tensile stress layer in which a tensile stress is generated is exposed on a side surface of the cover glass to be obtained in a case in which the large tempered glass is divided as in Patent Document 1. Thus, it is considered that it is difficult to manufacture a cover glass having a sufficient strength on a side surface thereof according to the method described in Patent Document 1.

Meanwhile, proposed is a method of providing resin on a side surface of a cover glass to enhance the strength on the side surface of the cover glass. For example, Patent Document 2 proposes a method of framing an outer peripheral surface of a cover glass including a side surface of the cover glass with a plastic membrane. An injection molding method, a dispensing method, a spray coating method, a roller coating method or the like is proposed as the framing method.

SUMMARY OF THE INVENTION

When the display device is seen from an observer side, the display device is partitioned into an active area in which a video is displayed, and a non-active area (so-called frame region) in a periphery thereof. Recently, not only a black color, which is conventionally employed in general, but also a white color and other various colors have been employed as colors of the frame region in order to enhance design effect of the display device. In general, such colors are implemented using a decorative portion which is provided on a surface, on a display device side, of the cover glass. It is important to sufficiently enhance external dimensional accuracy of the cover glass, that is, accuracy in processing the side surface of the cover glass in order to sufficiently enhance accuracy in processing the decorative portion with respect to the display device. In addition, there is a demand for the high external dimensional accuracy in the portable terminal equipped with the display device also at the time of assembling the cover glass, the display device and a case from a viewpoint of waterproofness or design effect. Accordingly, the external dimensional accuracy of the cover glass is also important on consideration of enhancing ease and a yield of the process.

Meanwhile, it is difficult to precisely control a coating dimension of the plastic membrane framing the outer peripheral surface of the cover glass in the method that is proposed in Patent Document 2. Thus, it is difficult to realize the high external dimensional accuracy of the cover glass, and as a result, it is considered that the design effect of the display device is damaged or the yield of the assembly process with the display device is reduced.

In addition, it is considered that processing of a cover glass in which a glass edge is exposed, such as adjusting an external dimension using physical polishing or curved surface processing of the outer peripheral portion for improvement of the design effect, is difficult because such additional processing of the outer peripheral portion of the cover glass introduces a remarkable decrease of the strength of the cover glass.

The present invention has been made in view of the above-described points, and an object thereof is to provide a cover glass, which is provided with a reinforcing portion formed at high external dimensional accuracy, and a cover glass-equipped display device.

The present invention relates to a method of manufacturing a cover glass to be provided in a display device, the method of manufacturing the cover glass including: a step of preparing a unit laminated body that includes a unit base member, which includes a first surface, a second surface on an opposite side of the first surface, and a side surface spreading between the first surface and the second surface and comprises a glass or the like, and a first protective film provided on the first surface of the unit base member, and a second protective film provided on the second surface; a coating step of applying a coating liquid containing a resin material on the side surface of the unit base member; and a curing step of curing the coating liquid on the side surface of the unit base member to form a reinforcing portion on the side surface of the unit base member, in which the first protective film is configured to laterally protrude than the first surface of the unit base member, and further, the second protective film is configured to laterally protrude than the second surface of the unit base member, and, in the coating step, the coating liquid is applied into a space surrounded by the side surface of the unit base member, the first protective film, and the second protective film.

In the method of manufacturing the cover glass according to the present invention, a position of an edge on a first surface of the reinforcing portion, which is formed in the curing step, may match a position of an end surface of the first protective film, and a position of an edge on a second surface of the reinforcing portion, which is formed in the curing step, may match a position of an end surface of the second protective film. Alternatively, an edge on a first surface of the reinforcing portion, which is formed in the curing step, may be positioned at an inner side than an end surface of the first protective film, and an edge on a second surface of the reinforcing portion, which is formed in the curing step, may be positioned at an inner side than an end surface of the second protective film.

In the method of manufacturing the cover glass according to the present invention, the unit base member may include a compressive stress layer, which is formed at least at the first surface and the second surface, and a tensile stress layer which is positioned between the compressive stress layer at the first surface side and the compressive stress layer at the second surface side. In this case, the tensile stress layer may be exposed to the side surface of the unit base member. Even when the tensile stress layer is exposed to the side surface of the unit base member, the reinforcing portion is formed such that the tensile stress layer exposed to the side surface of the unit base member is covered by the reinforcing portion, and thus, it is possible to sufficiently enhance an impact resistance of the cover glass.

In the method of manufacturing the cover glass according to the present invention, the unit base member may be obtained by performing a cutting step of cutting a base member comprising a tempered glass.

The method of manufacturing the cover glass according to the present invention may further include a protective film forming step of providing the first protective film and the second protective film in a plurality of predetermined sections on the first surface and the second surface of the base member, the protective film forming step performed prior to the cutting step. In this case, in the cutting step, the unit laminated body is obtained by cutting the base member along each clearance of the first protective film and the second protective film provided in each of the sections.

In the method of manufacturing the cover glass according to the present invention, the cutting step may include a step of cutting the base member by wet etching the base member from the first surface side and the second surface side of the base member using the first protective film and the second protective film as a resist.

The method of manufacturing the cover glass according to the present invention may further include an element portion forming step of forming at least a part of element portions including at least any one of a decorative portion and a touch panel sensor unit in the first surface side of the base member.

In the method of manufacturing the cover glass according to the present invention, the element portion forming step may be performed prior to the protective film forming step.

The present invention relates to a cover glass to be provided in a display device, the cover glass including: a unit base member which includes a first surface, a second surface positioned on an opposite side of the first surface, and a side surface spreading between the first surface and the second surface, and comprises a glass or the like; and a reinforcing portion which is provided on the side surface of the unit base member, and contains a resin material.

In the cover glass according to the present invention, the reinforcing portion may include a first surface laterally extending from an edge of the first surface of the unit base member, a second surface laterally extending from an edge of the second surface of the unit base member, and a side surface spreading between the first surface and the second surface of the reinforcing portion. In this case, preferably, a difference in level between the first surface of the unit base member and the first surface of the reinforcing portion is equal to or smaller than 10 μm, and a difference in level between the second surface of the unit base member and the second surface of the reinforcing portion is equal to or smaller than 10 μm.

In the cover glass according to the present invention, the unit base member may include a compressive stress layer, which is formed at least at the first surface and the second surface, and a tensile stress layer which is positioned between the compressive stress layer at the first surface side and the compressive stress layer at the second surface side. In this case, the tensile stress layer may be exposed to the side surface of the unit base member.

In the cover glass according to the present invention, a minimum value of a coating dimension of the reinforcing portion, which is provided on the side surface of the unit base member, is set to be equal to or larger than 20 μm.

In the cover glass according to the present invention, the side surface of the reinforcing portion may protrude than a virtual plane passing an edge of the first surface and an edge of the second surface of the reinforcing portion. In this case, a protruding amount of the side surface is preferably set to be equal to or smaller than 500 μm.

In the cover glass according to the present invention, the side surface of the reinforcing portion may be recessed than a virtual plane passing an edge of the first surface and an edge of the second surface of the reinforcing portion. In this case, a recessed amount of the side surface is preferably set to be equal to or smaller than 200 μm.

In the cover glass according to the present invention, the side surface of the unit base member may include a first side surface, which intersects the first surface of the unit base member and spreads outward as approaching the second surface side of the unit base member, and a second side surface which intersects the second surface of the unit base member, spreads outward as approaching the first surface side of the unit base member, and further, is merged into the first side surface.

In the cover glass according to the present invention, a decorative portion to exhibit a predetermined color may be provided in the first surface side of the unit base member. In this case, the reinforcing portion may be configured to exhibit the same color as the decorative portion.

In the cover glass according to the present invention, the decorative portion may be configured to overlap the reinforcing portion when seen along a normal direction of the cover glass.

In the cover glass according to the present invention, the reinforcing portion may be configured to exhibit a predetermined color.

In the cover glass according to the present invention, at least a part of a touch panel sensor unit may be provided on the first surface side of the unit base member.

In the cover glass according to the present invention, the unit base member may have a rectangular shape with four corners when seen in a plan view, and the reinforcing portion may be provided in a part including the four corners of the unit base member in the side surface of the unit base member.

In the cover glass according to the present invention, the reinforcing portion may be provided on the side surface of the unit base member such that the unit base member is surrounded by the reinforcing portion when seen in a plan view.

In the cover glass according to the present invention, a through-hole may be formed in the unit base member, and the reinforcing portion may be provided on a wall surface of the through-hole.

In the cover glass according to the present invention, a conductive particle may be added in the reinforcing portion.

In the cover glass according to the present invention, the resin material of the reinforcing portion may contain a polyene-polythiol-based photocurable resin.

In the cover glass according to the present invention, at least one of a part, of the side surface of the reinforcing portion, intersecting with the first surface of the reinforcing portion and a part thereof intersecting with the second surface of the reinforcing portion may have a round surface or an angular surface.

Another cover glass according to the present invention is a cover glass including: a unit base member which includes a first surface, a second surface on an opposite side of the first surface, and a side surface spreading between the first surface and the second surface, and comprises a glass; and a reinforcing portion which is provided on the side surface of the unit base member, and contains a resin material, in which the resin material of the reinforcing portion contains a polyene-polythiol-based photocurable resin.

The present invention relates to a cover glass-equipped display device which is provided with a display device and a cover glass disposed in the display device, and in which the cover glass is formed using the above-described cover glass.

According to the present invention, it is possible to provide the cover glass which is provided with the side surface formed at the high external dimensional accuracy.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference toFIGS. 1 to 7D. Incidentally, in the drawings appended to the present specification, scales and horizontal and vertical dimension ratios are appropriately changed and exaggerated as compared to actual ones thereof in order for convenience of illustration and facilitating the understanding.

First, a cover glass-equipped display device10will be described with reference toFIG. 1. As illustrated inFIG. 1, the cover glass-equipped display device10is configured by combining a display device15and a cover glass20. The display device15illustrated inFIG. 1is configured as a flat panel display. The display device15includes a display panel16having a display surface16a, and a display control unit (not illustrated) which is connected to the display panel16. The display panel16includes an active area A1, which is capable of displaying a video, and a non-active area (referred to also as a frame region) A2which is disposed on an outer side of the active area A1to enclose the active area A1. The display control unit processes information relating to the video that needs to be displayed and drives the display panel16on the basis of the video information. The display panel16displays the predetermined video on the display surface16abased on a control signal of the display control unit. That is, the display device15serves a role as an output device that outputs information such as a letter or a figure as the video.

As illustrated inFIG. 1, the cover glass20is disposed on the display surface16aof the display panel16on an observer side of the display device15. For example, this cover glass20is attached onto the display surface16aof the display device15via an adhesion layer (not illustrated). InFIG. 1, a surface of the cover glass20at the display device side (first surface) is represented by reference sign20a, and a surface thereof at the observer side (second surface) is represented by reference sign20b.

Incidentally, the cover glass20is configured to serve a touch panel function as well as a role to protect the display device15in the present embodiment. To be specific, a touch panel sensor unit40, which includes a sensor electrode to detect approach or contact of an external conductor, is provided on the first surface20aof the cover glass20at the display device15side. In addition, a decorative portion60, which is configured to exhibit a desired color, is further, provided in the non-active area Aa2of the first surface20aof the cover glass20.

Next, a description will be given regarding the touch panel sensor unit40, which is provided on the first surface20aof the cover glass20, with reference toFIG. 2.FIG. 2is a plan view illustrating a case in which the cover glass20is seen from the first surface20aside. Incidentally, the decorative portion60is not illustrated inFIG. 2for convenience of description.

The touch panel sensor unit40illustrated inFIG. 2is configured as an electrostatic capacitive coupling system of a projection type, and is configured to be capable of detecting a contact position (referred to also as a touch position) of an external conductor (for example, a human finger) at the touch panel sensor unit40. Incidentally, it is possible to detect any approach region of the external conductor in the touch panel device when the external conductor just approaches the touch panel sensor unit40in a case in which the touch panel sensor unit40of the electrostatic capacitive coupling system has an excellent detection sensitivity. Accordingly, the “contact position” used here is a concept including an approach position that may be detected although the position is not actually in contact. Incidentally, the “capacitive coupling” system is also called an “electrostatic capacitive” system or an “electrostatic capacitive coupling” system in the technical field of the touch panel, and is handled as a term having the same meaning as the “electrostatic capacitive” system or the “electrostatic capacitive coupling” system in the present application.

As illustrated inFIG. 2, the first surface20aof the cover glass20is partitioned into an active area Aa1, which corresponds to the region in which the touch position can be detected, and a non-active area Aa2, which is positioned in the periphery of the active area Aa1, in response to the active area A1and the non-active area A2of the display panel16. In addition, the touch panel sensor unit40is provided with a plurality of sensor electrodes41and42disposed in the active area Aa1, a plurality of take-out wirings43, which are disposed in the non-active area Aa2of the cover glass20and connected to the corresponding sensor electrodes41and42, and a plurality of terminal portions44which are connected to the corresponding take-out wirings43.

As illustrated inFIG. 2, the sensor electrodes41and42include a plurality of first sensor electrodes41extending along a first direction D1, and a plurality of second sensor electrodes42extending along a second direction D2which is orthogonal to the first direction D1. The first sensor electrode41may include a first line portion41alinearly extending along the first direction D1, and a first bulging portion41bbulging from the first line portion41a. The first bulging portion41bindicates a portion which bulges out from the first line portion41aalong the surface of the cover glass20. In the same manner, the second sensor electrode42may include a second line portion42aextending along the second direction D2, and a second bulging portion42bbulging from the second line portion42a.

The take-out wiring43is provided in the non-active area Aa2to transfer a signal detected by the corresponding sensor electrodes41and42to the terminal portion44. The signal, which has been transferred to the terminal portion44by the take-out wiring43, is transfer to a detection control unit via a flexible substrate (not illustrated) mounted to the terminal portion44.

(Layer Configuration of Cover Glass, Touch Panel Sensor Unit, and Decorative Portion)

Next, a description will be given regarding a layer configuration of the cover glass20, and the touch panel sensor unit40and the decorative portion60which are provided in the first surface20aof the cover glass20with reference toFIGS. 3 and 4.FIGS. 3 and 4are cross-sectional views which are taken along a line III and a line IV, respectively, of the cover glass20illustrated inFIG. 2.

First, a description will be given regarding a layer configuration of constituting elements which are disposed in the active area Aa1of the cover glass20. As illustrated inFIGS. 3 and 4, the first line portion41a, the first bulging portion41b, and the second bulging portion42bof the touch panel sensor unit40may be formed on the same plane. In this case, it is possible to form the first line portion41a, the first bulging portion41b, and the second bulging portion42bat the same time by patterning a transparent conductive layer51which is formed using a transparent conductive material such as indium tin oxide (ITO).

As illustrated inFIGS. 3 and 4, the first line portion41aand the second line portion42aare formed to partially overlap each other when seen in the normal direction of the cover glass20. In this case, it is possible to prevent conduction between the first line portion41aand the second line portion42aby providing an insulating layer47to be interposed between the first line portion41aand the second line portion42a. Incidentally, the insulating layer47may be provided on the first bulging portion41bor on the second bulging portion42b, although not illustrated, in addition to the portion between the first line portion41aand the second line portion42a.

A material to form the second line portion42ais not particularly limited as long as the second line portion42ahas conductivity. For example, the second line portion42amay be formed using the transparent conductive material such as the indium tin oxide (ITO) in the same manner as the first line portion41a, the first bulging portion41b, and the second bulging portion42b, or may be formed using a non-transparent conductive material such as a silver alloy or copper. In the present embodiment, a description will be given regarding an example in which the second line portion42ais formed using a metal layer52which is also included in the take-out wiring43and the terminal portion44.

Next, a description will be given regarding a layer configuration of constituting elements which are disposed in the non-active area Aa2of the cover glass20. As illustrated inFIGS. 3 and 4, the decorative portion60is disposed in the non-active area Aa2to be positioned at the observer side than the above-described take-out wiring43. In this case, the decorative portion60is visually recognized from the observer side through the cover glass20. That is, the appearance of the non-active area Aa2is determined by the decorative portion60and constituting elements in the periphery thereof in the cover glass-equipped display device10.

The color of the decorative portion60is selected according to the design effect to be acquired for the cover glass-equipped display device10. For example, examples of the color of the decorative portion60can include black, white, light blue, peach, green and the like. A material to form the decorative portion60is determined according to the selected color, and the decorative portion60is formed using a resin material in which coloring pigments such as titanium oxide are dispersed, for example, in the case of acquiring the white.

Next, a configuration of the cover glass20will be described. As illustrated inFIGS. 3 and 4, the cover glass20is provided with a unit base member22and a reinforcing portion26. The unit base member22includes a first surface22aat the display device side, a second surface22bat the opposite side of the first surface22a, and a side surface22cspreading between the first surface22aand the second surface22b. Further, the reinforcing portion26is provided on the side surface22cof the unit base member22.

As described below, the unit base member22is obtained by dividing a base member30formed using a large tempered glass into individual pieces. As illustrated inFIG. 5, this unit base member22includes a compressive stress layer24a, which is formed at the first surface22aand the second surface22b, and a tensile stress layer24bwhich is positioned between the compressive stress layer24aat the first surface22aside and the compressive stress layer24aat the second surface22bside. The compressive stress layer24aIndicates a layer in which a compressive stress is generated, and the tensile stress layer24bindicates a layer in which a tensile stress is generated. Examples of a method of forming the compressive stress layer24aand the tensile stress layer24binclude a physical strengthening (air-cooling and tempering) and a chemical strengthening. For example, chemical treatment is performed in the chemical strengthening in a manner such that alkali ions included in the glass is exchanged with other alkali ions with a larger ionic radius at the temperature equal to or lower than the strain point. Accordingly, it is possible to generate the compressive stress in the vicinity of a surface layer in which the ions are exchanged. When the compressive stress layer24ais formed, it is possible to prevent spreading of scratch even in a case in which a certain impact is applied to the first surface22aor the second surface22b, and accordingly, the scratch such as a crack is formed on the first surface22aor the second surface22b. Thus, the first surface22aand the second surface22bof the unit base member22have high resistance with respect to the impact. It is possible to use aluminosilicate glass, for example, as a material to form the unit base member22. A thickness of the compressive stress layer24ais generally set within a range of 10 to 100 μm.

Meanwhile, the tensile stress layer24bof the unit base member22reaches the side surface22cof the unit base member22as illustrated inFIG. 5. That is, the tensile stress layer24bis exposed on the side surface22cof the unit base member22. Thus, the side surface22cof the unit base member22is vulnerable to the damage such as the crack as compared to the first surface22aand the second surface22bof the unit base member22. The above-described reinforcing portion26is provided to protect the side surface22cof the unit base member22formed in such a manner.

A curable resin, which is cured by heating, ultraviolet irradiation or the like, for example, is used as a material to form the reinforcing portion26. In this case, the reinforcing portion26has a desired liquidity when being molded before curing, and further, the reinforcing portion26has desired hardness and strength after being cured. Accordingly, it is possible to acquire both the moldability and the hardness and strength.

In a case in which the reinforcing portion26includes the curable resin cured by ultraviolet irradiation, it is possible to use a combination of an acrylic resin and a photopolymerization initiator, for example, as the material to form the reinforcing portion26.

In a case in which the reinforcing portion26includes the curable resin cured by heating, it is possible to use an epoxy resin, for example, as the material to form the reinforcing portion26.

Next, a description will be given more in detail regarding shapes of the side surface22cof the unit base member22and the reinforcing portion26with reference toFIG. 5.FIG. 5is a cross-sectional view illustrating the side surface20cof the cover glass20ofFIG. 3in an enlarged manner.

First, the shape of the reinforcing portion26will be described. As illustrated inFIG. 5, the reinforcing portion26includes a first surface26awhich laterally extends from the vicinity of an edge22aeof the first surface22aon the same plane with the first surface22aof the unit base member22, a second surface26bwhich laterally extends from the vicinity of an edge22beof the second surface22bon the same plane as the second surface22bof the unit base member22, and a side surface26cspreading between the first surface26aand the second surface26bof the reinforcing portion26. Hereinafter, a description will be given regarding advantages that are brought about by the reinforcing portion26including the first surface26aand the second surface26bas above.

First, a description will be given regarding a problem which considered in Patent Document 2 described above for comparison. When a reinforcing portion to reinforce a side surface of a base member is provided by framing an outer peripheral surface of the base member as in Patent Document 2, a difference in level is formed between a plane of the reinforcing portion and a plane of the base member. Accordingly, scattering of light or a great change in transmittance and reflectance of light is easily caused in a boundary between the reinforcing portion and the base member. As a result, the boundary between the reinforcing portion and the base member is likely to be visually recognized by the observer. That is, it is considered that the design effect of the cover glass is reduced. In addition, a feeling of operating a touch panel is inhibited due to the difference in level in a case in which the reinforcing portion of the cover glass is exposed to the outside.

On the contrary, the first surface22aof the unit base member22and the first surface26aof the reinforcing portion26are positioned on the same plane according to the present embodiment. In the same manner, the second surface22bof the unit base member22and the second surface26bof the reinforcing portion26are positioned on the same plane. That is, a difference in level is completely or almost not present between the unit base member22and the reinforcing portion26. To be specific, a difference in level between each of the first surface22aand the second surface22bof the unit base member22, and each of the first surface26aand the second surface26bof the reinforcing portion26is equal to or smaller than 10 μm. Thus, it is possible to suppress a boundary between the unit base member22and the reinforcing portion26from being visually recognized by the observer. Accordingly, it is possible to secure both the strength of the side surface20cof the cover glass20and the design effect of the cover glass20according to the reinforcing portion26of the present embodiment. In addition, the feeling of operating the touch panel is not inhibited by the difference in level. In addition, the thickness of the compressive stress layer24ais generally set within the range of 10 to 100 μm as described above. Accordingly, the compressive stress layer24aof the unit base member22and the reinforcing portion26at least partially overlap each other in the side surface22cof the unit base member22in a case in which the difference in level between each of the first surface22aand the second surface22bof the unit base member22and each of the first surface26aand the second surface26bof the reinforcing portion26is equal to or smaller than 10 μm, that is, a case in which the difference in level is smaller than the thickness of the compressive stress layer24a. Accordingly, it is possible to cover the tensile stress layer24bexposed to the side surface22cof the unit base member22with the reinforcing portion26without any clearance. Thus, it is possible to more reliably enhance the impact resistance of the cover glass20.

Preferably, each of the first surface26aand the second surface26bof the reinforcing portion26is laterally extended from the edge22aeand the edge22beby at least 300 μm on the same plane with the first surface22aand the second surface22bof the unit base member22. Accordingly, it is possible to more reliably secure the strength of the side surface20cof the cover glass20and the design effect of the cover glass20. Incidentally, the expression of “on the same plane” means that an interval, in the thickness direction of the unit base member22, between each part of the first surface26aand the second surface26bof the reinforcing portion26laterally extending from the edge22aeand the edge22beby at least 300 μm, and each of the first surface22aand the second surface22bof the unit base member22is equal to or smaller than 10 μm, similarly as in the case of the above-described difference in level.

Next, the side surface26cof the reinforcing portion26will be described. InFIG. 5, an edge of the first surface26aof the reinforcing portion26is represented by reference sign26ae, and an edge of the second surface26bof the reinforcing portion26is represented by reference sign26be. As illustrated inFIG. 5, the side surface26cis configured as a flat surface which substantially evenly spreads between the edge26aeand the edge26be. Further, the first surface26aand the side surface26cintersect each other at a substantially right angle, and similarly, the second surface26band the side surface26cintersect each other at a substantially right angle. That is, a position of the edge26aeand a position of the edge26bematch each other in the horizontal direction ofFIG. 5(extending direction of the first surface26aand the second surface26b).

Next, the shape of the side surface22cof the unit base member22will be described. As illustrated inFIG. 5, the side surface22cof the unit base member22includes a first side surface22dand a second side surface22e. The first side surface22dintersects the edge22aeof the first surface22aof the unit base member22, and spreads outward as approaching the second surface22bside of the unit base member22. In addition, the second side surface22eintersects the edge22beof the second surface22bof the unit base member22, spreads outward as approaching the first surface22aside of the unit base member22, and further, is merged into the first side surface22d. Thus, a merging portion of the first side surface22dand the second side surface22eprotrudes to the outer side. In this case, the reinforcing portion26has a shape of sandwiching the side surface22cof the unit base member22, and thus, it is possible to firmly bring the reinforcing portion26into close contact with the side surface22cof the unit base member22.

The first side surface22dand the second side surface22ehaving the above-described shapes are formed by, for example, wet etching the base member30from both the first surface side and the second surface side of the base member30at the time of dividing the base member30and obtaining the unit base member22as described below.

(Dimension of Cover Glass)

Next, a dimension of the cover glass20will be described. First, a description will be given regarding a coating dimension of the reinforcing portion26provided on the side surface22cof the unit base member22. Here, the coating dimension indicates a length of the reinforcing portion26in a direction along the normal direction of the side surface26cof the reinforcing portion26. The normal direction of the side surface26cof the reinforcing portion26is parallel to the horizontal direction ofFIG. 5.

InFIG. 5, a minimum value of the coating dimension of the reinforcing portion26is represented by reference sign Tmin. Incidentally, the first side surface22dof the unit base member22spreads outward as approaching the second surface22bside in the present embodiment as described above. In addition, the second side surface22eof the unit base member22spreads outward as approaching the first surface22aside. In addition, the side surface26cof the reinforcing portion26is formed as the flat surface which intersects the first surface26aand the second surface26bat the right angle as described above. Thus, the coating dimension of the reinforcing portion26has the minimum value Tmin at the position at which the first side surface22dand the second side surface22eare merged as illustrated inFIG. 5.

The minimum value Tmin of the coating dimension of the reinforcing portion26is suitably set so as to be capable of protecting the side surface22cof the unit base member22even in a case in which the impact is applied to the side surface20cof the cover glass20and the like. For example, the minimum value Tmin of the coating dimension of the reinforcing portion26is set to be equal to or larger than 20 μm.

In addition, the coating dimension of the reinforcing portion26has a maximum value at the position of the first surface26aor the position of the second surface26bin the present embodiment. Meanwhile, when the maximum value of the coating dimension of the reinforcing portion26is too large, it is considered that the reinforcing portion26is easily peeled off from the unit base member22when the impact is applied to the cover glass20. In addition, a proportion of the glass is decreased, and a proportion of the resin is increased in the cover glass20, and thus, it is also considered that the strength of the cover glass20decreases. On consideration of this point, it is preferable that the maximum value of the coating dimension of the reinforcing portion26is set to be equal to or smaller than 250 μm in a part at which the coating is the thinnest (the part represented by reference sign Tmin inFIG. 5), and is set to be equal to or smaller than 500 μm in a part at which the coating is the thickest (the part represented by reference sign Tmax inFIG. 5).

For example, it is considered that the coating dimension Tmin of the reinforcing portion26in the part at which the coating is the thinnest is set to 100 μm, and the coating dimension Tmax of the reinforcing portion26in the part at which the coating is the thickest is set to 300 μm in the example illustrated inFIG. 5.

A thickness of the cover glass20(that is, a thickness of the unit base member22and a thickness of the reinforcing portion26) is suitably set depending on the strength to be acquired, the area of the cover glass20, or the like, and, for example, is set within a range of 0.1 mm to 1 mm.

(Method of Manufacturing Cover Glass)

Next, a description will be given regarding a method of manufacturing the cover glass20which has the above-described configuration with reference toFIGS. 6A to 7D.

First, a description will be given regarding a step of forming a unit laminated body35which includes the unit base member22and protective films81and82using the base member30made of the large tempered glass with reference toFIGS. 6A to 6E(b). Incidentally,FIGS. 6A, 6B(a),6C,6D(a) and6E(a) are cross-sectional views illustrating the base member30in this step. In addition,FIG. 6E(b) is a cross-sectional view illustrating the unit laminated body35illustrated inFIG. 6E(a) in an enlarged manner. In addition,FIGS. 6B(b) and6D(b) are plan views illustrating the base member30in this step.

First, the base member30made of the large tempered glass is prepared as illustrated inFIG. 6A. The base member30includes a first surface30a, a second surface30bon the opposite side of the first surface30a, and a side surface30cspreading between the first surface30aand the second surface30b. As illustrated inFIG. 6A, the compressive stress layer24ais formed at the first surface30a, the second surface30b, and the side surface30cof the base member30, and further, the tensile stress layer24bis present at the inner side of the compressive stress layer24a. In this manner, the entire surface of the base member30is formed using the compressive stress layer24a.

Next, the decorative portion60and the touch panel sensor unit40are formed in a plurality of predetermined sections on the first surface30aof the base member30as illustrated inFIGS. 6B(a) and6B(b) (an element portion forming step). For example, inFIG. 6B(b), the decorative portion60and the touch panel sensor unit40are formed in each of six sections which are obtained by partitioning the first surface30aof the base member30into two rows in the vertical direction of the paper plane, and three columns in the horizontal direction of the paper plane. Incidentally, the number of the sections of the base member30is not particularly limited. A known method is appropriately used as a method of forming the decorative portion60and the touch panel sensor unit40on the first surface30aside, and, for example, a photolithographic method is used. Incidentally, the touch panel sensor unit40and the decorative portion60are collectively referred to as an element portion70in some cases in the following description.

Thereafter, a protective film forming step is performed in which the first protective film81and the second protective film82are provided in the plurality of predetermined sections on the first surface30aand the second surface30bof the base member30. First, the first protective film81to continuously cover the element portion70provided in each of the plurality of sections is provided on the first surface30aof the base member30as illustrated inFIG. 6C. In addition, the second protective film82is provided on the second surface30bof the base member30. In the example illustrated inFIG. 6C, each of the first protective film81and the second protective film82is provided to cover the entire region of the first surface30aand the second surface30bof the base member30.

The protective films81and82function as a resist to protect the element portion70at the time of dividing the base member30by wet etching, which will be described later, using hydrofluoric acid or the like. A material to form the protective films81and82is not particularly limited as long as the material has a resistance with respect to the etchant to be used for division of the base member30. For example, it is possible to use a biaxially-oriented polypropylene or an unstretched polypropylene having a thickness of approximately 50 to 100 μm as the material to form the protective films81and82. In this case, the protective films81and82are configured by pasting a sheet of the biaxially-oriented polypropylene or the unstretched polypropylene onto the first surface30aand the second surface30bof the base member30via an adhesive layer having a thickness of approximately 20 μm.

Thereafter, as illustrated inFIGS. 6D(a) and6D(b), the first protective film81and the second protective film82, provided over the entire region of the first surface30aand the second surface30b, are divided into each section of the first surface30aand the second surface30b. Accordingly, a clearance is formed along each boundary of the sections in the first protective film81covering each of the element portions70and the second protective film82corresponding thereto.

Various methods can be employed without particularly limiting a specific method of dividing the first protective film81and the second protective film82. For example, a mold having a shape corresponding to a shape of the first protective film81, illustrated inFIG. 6D(b), may be used to remove an unnecessary part (part which becomes the clearance) of the first protective film81. It is possible to remove an unnecessary part (part which becomes the clearance) of the second protective film82on the second surface30bside also using a mold having a shape corresponding to the mold for the first protective film81. Besides, laser processing may be used to remove the unnecessary parts of the first protective film81and the second protective film82.

Thereafter, a cutting step is performed as illustrated inFIG. 6E(a) in which the base member30is cut along each clearance of the first protective film81and the second protective film82provided in each section of the base member30. To be specific, the base member30is cut by wet etching the base member30from the first surface30aside and the second surface30bside of the base member30using the first protective film81and the second protective film82as the resist. The hydrofluoric acid or the like is used as the etchant as described above. Accordingly, it is possible to obtain the unit laminated body35that includes the unit base member22made of glass, the element portion70provided on the first surface22aside of the unit base member22, the first protective film81, which is provided on the first surface22aof the unit base member22and covers the element portion70, and the second protective film82provided on the second surface22bof the unit base member22as illustrated inFIG. 6E(a).

FIG. 6E(b) is a cross-sectional view illustrating the unit laminated body35illustrated inFIG. 6E(a) in an enlarged manner. As illustrated inFIG. 6E(b), the first protective film81is configured to laterally protrude than the first surface22aof the unit base member22. In the same manner, the second protective film82is configured to laterally protrude than the second surface22bof the unit base member22. Such a relationship between the unit base member22, and the first protective film81or the second protective film82is realized by continuing the etching step over the time of a degree that allows the unit base member22to be penetrated by etching from both sides of the first surface22aand the second surface22bof the unit base member22during the above-described cutting step using the etchant. Incidentally, in general, the etching isotropically proceeds in any of the depth direction and the horizontal direction at positions near the first surface22aand the second surface22bin the side surface22cof the unit base member22in the etching step. Thus, the etching greatly proceeds in the side surface22cof the unit base member22near the first surface22aand the second surface22bas compared to an intermediate position between the first surface22aand the second surface22bas illustrated inFIG. 6E(b). As a result, it is possible to obtain the first side surface22d, which intersects the edge22aeand spreads outward as approaching the second surface22bside, and the second side surface22ewhich intersects the edge22beand spreads outward as approaching the first surface22aside.

Next, a description will be given regarding a step for obtaining the cover glass20with the reinforced side surface by providing the reinforcing portion (resin or the like) on the side surface22cof the unit base member22of the unit laminated body35with reference toFIGS. 7A to 7D.

First, a coating step is performed in which a coating liquid27including a curable material such as a UV-curable resin or a thermosetting resin is applied on the side surface22cof the unit base member22as illustrated inFIG. 7A. Here, a description will be given regarding the case of using the coating liquid including the acrylic resin and the photopolymerization initiator.

In the coating step, a space, which is surrounded by the side surface22cof the unit base member22, the first protective film81and the second protective film82is filled with the coating liquid27as illustrated inFIG. 7A. Incidentally, the coating liquid27may be applied at a degree of being spilled out also onto an end surface81cof the first protective film81and onto an end surface82cof the second protective film82as illustrated inFIG. 7A.

Next, the coating liquid27spilled out onto the end surface81cof the first protective film81and onto the end surface82cof the second protective film82is scrapped off using a squeegee or the like. Accordingly, the surface of the coating liquid27matches the end surface81cof the first protective film81and the end surface82cof the second protective film82as illustrated inFIG. 7B. That is, a position of an edge of a liquid surface of the coating liquid27on the first protective film81side matches a position of the end surface81cof the first protective film81, and a position of an edge of a liquid surface of the coating liquid27on the second protective film82side matches a position of the end surface82cof the second protective film82.

Thereafter, a curing step is performed in which the coating liquid27provided on the side surface22cof the unit base member22is cured. Here, the coating liquid27is cured by irradiating the coating liquid27with light such as an ultraviolet ray. Accordingly, the reinforcing portion26is formed on the side surface22cof the unit base member22.

Next, the first protective film81on the first surface22aof the unit base member22, and the second protective film82on the second surface22bof the unit base member22are removed. Accordingly, it is possible to obtain the cover glass20which is provided with the unit base member22and the reinforcing portion26provided on the side surface22cof the unit base member22as illustrated inFIG. 7C. Thereafter, an additional decorative layer62may be provided at a position on the outer side of the decorative portion60while being on the first surface22aside of the unit base member22or the first surface26aside of the reinforcing portion26as illustrated inFIG. 7D. The additional decorative layer62is configured to exhibit the same color as the decorative portion60. When the above-described additional decorative layer62is further provided, it is possible to acquire improvement of the design effect such as prevention of light leakage from the outer peripheral portion by further expanding the range of the non-active area Aa2to enable exhibition of a desired color. In addition, it is preferable that the additional decorative layer62is configured to overlap the reinforcing portion26when seen in the normal direction of the first surface20aof the cover glass20.

According to the present embodiment, the reinforcing portion26including the curable resin is provided on the side surface22cof the unit base member22. Thus, when the impact is applied to the side surface20cof the cover glass20, the force transferred to the side surface22cof the unit base member22is mitigated by the reinforcing portion26, and thus, it is possible to suppress the generation of the damage such as the crack in the side surface22cof the unit base member22. Accordingly, it is possible to sufficiently enhance the impact resistance of the cover glass20even in a case in which the compressive stress layer is not formed at the side surface22cof the unit base member22. In addition, even in a case in which the tensile stress layer24bis exposed to the side surface22cof the unit base member22, it is possible to cover the exposed tensile stress layer24bwith the reinforcing portion26, and thus, it is possible to sufficiently enhance the impact resistance of the cover glass20.

In addition, the reinforcing portion26is formed inside the space positioned by the first protective film81laterally protruding from the first surface22aof the unit base member22and the second protective film82laterally protruding from the second surface22bof the unit base member22in the present embodiment as described above. Thus, the first surface22aof the unit base member22and the first surface26aof the reinforcing portion26are positioned on the same plane as illustrated inFIGS. 7C and 7D. In the same manner, the second surface22bof the unit base member22and the second surface26bof the reinforcing portion26are positioned on the same plane. That is, a difference in level is completely or almost not present between the unit base member22and the reinforcing portion26. Thus, it is possible to suppress a boundary between the unit base member22and the reinforcing portion26from being visually recognized by the observer. Accordingly, it is possible to secure both the strength of the side surface20cof the cover glass20and the design effect of the cover glass20according to the reinforcing portion26of the present embodiment. In addition, the feeling of operating the touch panel is not inhibited by the difference in level.

In addition, the side surface26cof the reinforcing portion26is aligned in the reinforcing portion26by scrapping off the coating liquid27, which has been spilled out onto the end surface81cof the first protective film81and the end surface82cof the second protective film82, using a squeegee or the like, in the present embodiment as described above. Thus, the position of the edge26aeof the first surface26amatches the position of the end surface81cof the first protective film81in the reinforcing portion26, which is obtained by curing the coating liquid27. In the same manner, the position of the edge26beof the second surface26bof the reinforcing portion26matches the position of the end surface82cof the second protective film82. As described above, it is possible to determine the position of the edge26aeof the first surface26aand the position of the edge26beof the second surface26bof the reinforcing portion26based on the positions of the end surfaces81cand82cof the protective films81and82according to the present embodiment.

As described above, the reinforcing portion26is formed using the coating liquid27with a predetermined liquidity. Accordingly, it is difficult to precisely control a dimension such as a thickness and a shape of the coating liquid27if the coating liquid27is applied without using a frame such as the protective films81and82. Meanwhile, the positions of the end surfaces81cand82cof the protective films81and82are determined with high accuracy through processing using the mold or the laser as described above. Accordingly, it is possible to realize the accuracy conforming to the accuracy of the processing using the mold or the laser as the accuracy in the dimension such as the thickness and the shape of the coating liquid27according to the present embodiment. Thus, it is possible to accurately set the positions of the edges26aeand26beof the reinforcing portion26, that is, the position of the edge of the cover glass20according to the present embodiment. Accordingly, it is possible to enhance the ease and yield of the process at the time of assembling the cover glass20, the display device15, and the case. In addition, it is also possible to enhance the processing accuracy of the decorative portion60and the touch panel sensor unit40with respect to the display device15in a case in which the decorative portion60and the touch panel sensor unit40are provided in the cover glass20as in the present embodiment. Accordingly, it is possible to realize excellent design effect and operability of the cover glass-equipped display device10.

In addition, when the side surface26cof the reinforcing portion26is configured as the flat surface which substantially evenly spreads between the edge26aeand the edge26be, not only the positions of the edges26aeand26beof the reinforcing portion26but also a position of the entire side surface26cof the reinforcing portion26is also set in response to the positions of the end surfaces81cand82cof the protective films81and82. That is, it is possible to enhance the processing accuracy not only in the edge of the cover glass20but also in the entire side surface20cof the cover glass20.

In addition the side surface20cof the cover glass20is formed using the reinforcing portion26including the resin according to the present embodiment, and thus, it is unnecessary to perform laceration prevention processing through chamfering or the like with respect to an edge portion of the side surface20cof the cover glass20as compared to the case of forming the side surface20cof the cover glass20using the glass.

In addition, it is preferable that the reinforcing portion26of the cover glass20is configured to exhibit the same color as the decorative portion60and the additional decorative layer62provided on the first surface20aside of the cover glass20. For example, the reinforcing portion26may include a coloring pigment having the same color as the coloring pigment included in the decorative portion60and the additional decorative layer62. In this case, a region in the periphery of the outer frame of the non-active area Aa2is visually recognized as a region having the same color as the region of the decorative portion60or the additional decorative layer62positioned on the inner side thereof. Thus, it is possible to obtain the same effect in design as those in a case in which the decorative portion60and the additional decorative layer62extend to the outer frame of the non-active area Aa2.

In general, the decorative portion60and the additional decorative layer62are formed by applying a coating liquid containing a resin material and pigments on the cover glass20(on the unit base member22or the reinforcing portion26). Meanwhile, it is not easy to accurately coat the region in the periphery of the outer frame of the non-active area Aa2with the coating liquid.

Here, when the reinforcing portion26is colored as described above, the region in the periphery of the outer frame of the non-active area Aa2is visually recognized with the desired color without providing the decorative portion60and the additional decorative layer62even in the region in the periphery of the outer frame of the non-active area Aa2. Thus, it is possible to make the steps of providing the decorative portion60and the additional decorative layer62easier.

Incidentally, the “same color” means that chromaticity of two colors approximate each other to a degree in which a difference between the colors is hardly discriminated with the naked eye. To be more specific, the “same color” means that a color difference ΔE*abbetween two colors is equal to or smaller than 10, and preferably, equal to or smaller than 3. In addition, “different colors” mean that a color difference ΔE*abbetween two colors is larger than 10. Here, the color difference ΔE*abindicates a value which is calculated based on L*, a* and b* in the L*a*b* color system, and is a value serving as an index relating to a difference in color in the case of observation with the naked eye.

Incidentally, it is possible to add various alterations with respect to the embodiment described above. Hereinafter, several modified examples will be described with reference to the drawings. In the following description and drawings to be used in the following description, parts that can be configured in the same manner as the above-described embodiment will be represented by the same reference signs as the reference sings which have been used for the corresponding parts in the above-described embodiment, and the repeated description will be omitted. In addition, when it is apparent that it is possible to obtain the operational effect, which can be obtained in the embodiment described above, even in the modified example, the description thereof will be omitted.

In the above-described present embodiment, the example has been illustrated in which the element portion forming step of forming the element portion70, which includes the decorative portion60, the touch panel sensor unit40and the like, on the first surface30aof the base member30is performed prior to the protective film forming step of providing the first protective film81and the second protective film82in the base member30. However, the first protective film81and the second protective film82may be provided with respect to the base member30in a state in which the element portion70is not provided.FIG. 8Ais a cross-sectional view illustrating the unit laminated body35which is obtained by cutting the base member30in which the element portion70is not provided along each clearance of the first protective film81and the second protective film82. Even in this case, the space surrounded by the side surface22cof the unit base member22, the first protective film81, and the second protective film82is filled with the coating liquid27, and it is possible to obtain the cover glass20that includes the reinforcing portion26provided on the side surface22cof the unit base member22as illustrated inFIG. 8B. Thereafter, the decorative portion60and the touch panel sensor unit40may be formed on the first surface20aof the cover glass20. Alternatively, it may be configured such that the decorative portion60and the touch panel sensor unit40are individually formed, and then, are combined using an adhesive or the like, to form the cover glass20, and then, the resultant is combined with the display device15.

The reinforcing portion26may be configured to exhibit a predetermined color in the first modified example illustrated inFIGS. 8A and 8B. For example, the reinforcing portion26may contain a coloring pigment to exhibit the predetermined color. In this case, it is possible to realize the improvement of the design effect such as the prevention of light leakage from the outer peripheral portion without providing the decorative portion60and the additional decorative layer62.

In the above-described first modified example, the example has been illustrated in which the first protective film81and the second protective film82are provided with respect to the base member30in a state in which none of the decorative portion60and the touch panel sensor unit40are provided. However, the first protective film81and the second protective film82may be provided with respect to the base member30in a state in which the touch panel sensor unit40is not provided but the decorative portion60is provided.FIG. 9Ais a cross-sectional view illustrating the unit laminated body35which is obtained by cutting the base member30in which the decorative portion60is provided along each clearance of the first protective film81and the second protective film82. Even in this case, it is possible to obtain the cover glass20provided with the reinforcing portion26, which is provided on the side surface22cof the unit base member22, as illustrated inFIG. 9B, by filling the space surrounded by the side surface22cof the unit base member22, the first protective film81, and the second protective film82with the coating liquid27. Thereafter, the touch panel sensor unit40may be formed on the first surface20aof the cover glass20. Alternatively, it may be configured such that the touch panel sensor unit40is individually formed, and then, is combined using an adhesive or the like, to form the cover glass20, and then, the resultant is combined with the display device15.

In the above-described present embodiment, the example has been illustrated in which the protective film forming step of providing the first protective film81and the second protective film82in the base member30is performed prior to the cutting step of cutting the base member30and obtaining the unit base member22. However, the first protective film81and the second protective film82may be provided on the first surface22aand the second surface22bof the unit base member22after cutting the base member30and obtaining the unit base member22. In this case, it is possible to use a unit base member in which the compressive stress layer24ais formed at not only the first surface22aand the second surface22bof the unit base member22but also the side surface22c, as illustrated inFIG. 10A, as the unit base member22

Incidentally, it is effective to provide the reinforcing portion26on the side surface22cof the unit base member22when the impact is applied to the side surface20cof the cover glass20even in a case in which the side surface22cof the unit base member22is formed using the compressive stress layer24a, in order to mitigate the force transferred to the side surface22cof the unit base member22. First, the first protective film81and the second protective film82are provided on the first surface22aand the second surface22bof the unit base member22, as illustrated inFIG. 10B, in order to provide the reinforcing portion26on the side surface22c. The first protective film81and the second protective film82are provided to laterally protrude from the first surface22aand the second surface22bof the unit base member22as illustrated inFIG. 10B. Thereafter, the space surrounded by the side surface22cof the unit base member22, the first protective film81, and the second protective film82is filled with the coating liquid27, and further, the coating liquid27is cured, whereby, it is possible to obtain the cover glass20provided with the reinforcing portion26provided on the side surface22cof the unit base member22as illustrated inFIG. 10C.

Incidentally, the decorative portion60and the touch panel sensor unit40may be formed on the first surface20aside of the cover glass20after obtaining the cover glass20also in the present modified example similarly to the cases of the first modified example and the second modified example described above.

In the above-described present embodiment, the example has been illustrated in which the first side surface22dof the unit base member22intersects the edge22aeof the first surface22aof the unit base member22and spreads outward as approaching the second surface22bside of the unit base member22, and further, the second side surface22eof the unit base member22intersects the edge22beof the second surface22bof the unit base member22, spreads outward as approaching the first surface22aside of the unit base member22, and then is merged into the first side surface22d. That is, the example has been illustrated in which the side surface22cof the unit base member22has a convex shape to protrude toward the outer side. However, the side surface22cof the unit base member22may have a concave shape to be recessed toward the inner side, as illustrated inFIG. 11. In this case, it is possible to obtain the cover glass20with high contour accuracy by molding the reinforcing portion26using the first protective film81and the second protective film82similarly to the case of the above-described present embodiment.

In the above-described present embodiment, the example has been illustrated in which the side surface26cof the reinforcing portion26is configured as the flat surface, which substantially evenly spreads between the edge26aeand the edge26be. However, the side surface26cof the reinforcing portion26may protrude than a virtual plane P passing the edge26aeof the first surface26aand the edge26beof the second surface26bof the reinforcing portion26, as illustrated inFIG. 12. In this case, it is possible to allow the reinforcing portion26to cover the side surface22cof the unit base member22more thickly as compared to a case in which the side surface26cof the reinforcing portion26is flat, and thus, it is possible to more effectively protect the side surface22cof the unit base member22.

InFIG. 12, a protruding amount of the side surface26cwith respect to the plane P is represented by reference sign S1. The protruding amount S1is suitably set according to the contour accuracy to be acquired for the cover glass20, and, for example, the protruding amount S1is set to be equal to or smaller than 500 μm.

In the above-described fifth modified example, the example has been illustrated in which the side surface26cof the reinforcing portion26protrudes than the virtual plane P passing the edge26aeof the first surface26aand the edge26beof the second surface26bof the reinforcing portion26, but the invention is not limited thereto. As illustrated inFIG. 13, the side surface26cof the reinforcing portion26may be recessed than the virtual plane P. That is, the edge26aeof the first surface26aand the edge26beof the second surface26bof the reinforcing portion26may laterally protrude than the side surface26c. In this case, the impact from the outside is easily applied to the edges26aeand26bethan the side surface26c.

It is considered that a part, which is most likely to be damaged in the side surface22cof the unit base member22, is a part in which the first side surface22dand the second side surface22eare merged in the example illustrated inFIG. 13. The reason is because there is a high possibility that the merging portion of the first side surface22dand the second side surface22elaterally protrude, and the merging portion is positioned in the tensile stress layer24bin the case of cutting the base member30using the wet etching. Meanwhile, this merging portion is generally positioned at a location, which is spaced apart from the edge26aeand the edge26be, for example, a location in the middle between the edge26aeand the edge26be. Here, the impact from the outside is likely to apply to the edges26aeand26beaccording to the present modified example, and thus, it is possible to suppress the impact from affecting the above-described merging portion positioned at the location spaced apart from the edges26aeand26be. Thus, it is possible to more effectively prevent the damage of the side surface22cof the unit base member22.

InFIG. 13, a recessed amount of the side surface26cwith respect to the plane P is represented by reference sign S2. The recessed amount S2is suitably set according to the contour accuracy to be acquired for the cover glass20, and, for example, the recessed amount S2is set to be equal to or smaller than 200 μm.

In the above-described present embodiment, the example has been illustrated in which the decorative portion60and the reinforcing portion26do not overlap each other when seen along the normal direction of the first surface20aof the cover glass20. However, the decorative portion60and the reinforcing portion26may overlap each other when seen along the normal direction of the first surface20aof the cover glass20, as illustrated inFIG. 14. In this case, the region in the periphery of the outer frame of the non-active area Aa2can be visually recognized in a desired color without providing the additional decorative layer62described above. Thus, it is possible to reduce labor and cost required for manufacturing of the cover glass20as compared to the case of providing the additional decorative layer62.

(Modified Example of Protective Film)

In the above-described present embodiment, the example has been illustrated in which an outer surface of the first protective film81(the surface on the opposite side of a surface on the unit base member22side among surfaces of the first protective film81) is flat, for example, as illustrated inFIG. 6E(b). However, it is considered that the outer surface of the first protective film81has a shape following each shape of the decorative portion60and the touch panel sensor unit40on the unit base member22, as illustrated inFIG. 15A, in a case in which the first protective film81is configured using a photosensitive resist film.

Incidentally, there is a case in which it is difficult to make the shape of the first protective film81follow the shapes of the decorative portion60and the touch panel sensor unit40on the unit base member22, and as a result, a clearance is formed between the first protective film81and the first surface22aof the unit base member22, as illustrated inFIG. 15B(a), when the thickness of the decorative portion60is large (for example, when the decorative portion60is a white-based object) or when a distance from an outer edge of the decorative portion60to the end surface81cof the first protective film81is short. In this case, the first surface26aof the reinforcing portion26is not present on the same plane as the first surface22aof the unit base member22as illustrated inFIG. 15B(b). Incidentally, even in the example illustrated inFIGS. 15B(a) and15B(b), the position of the edge26aeof the reinforcing portion26matches the position of the end surface81cof the first protective film81similarly to the case of the above-described present embodiment. That is, it is possible to accurately set the position of the edge26aeof the reinforcing portion26, that is, the position of the edge of the cover glass20even in the present modified example.

Incidentally, when it is difficult to make the shape of the first protective film81follow the shapes of the decorative portion60and the touch panel sensor unit40on the unit base member22, the decorative portion60may be configured such that an end surface60cof the decorative portion60projects out to the outer side than the side surface22cof the unit base member22as illustrated inFIG. 15C(a). In this case, a space surrounded by the side surface22cof the unit base member22, the decorative portion60, and the second protective film82is filled with the coating liquid for formation of the reinforcing portion26. Thus, it is possible to obtain the cover glass20in which the first surface22aof the unit base member22and the first surface26aof the reinforcing portion26are positioned on the same plane as illustrated inFIG. 15C(b). Incidentally, the position of the edge26aeof the reinforcing portion26matches a position of the end surface60cof the decorative portion60in the example illustrated inFIGS. 15C(a) and15C(b). In addition, the decorative portion60is formed by a photolithographic method, in general. Accordingly, it is possible to realize the accuracy conforming to the accuracy in the photolithographic method as the accuracy in the dimension such as the thickness and the shape of the reinforcing portion26according to the present modified example. That is, it is possible to accurately set the position of the edge26aeof the reinforcing portion26, that is, the position of the edge of the cover glass20even in the present modified example.

(Modified Example of Configuration of Coating Liquid)

In addition, in the above-described present embodiment, the example has been illustrated in which the coating liquid27to be applied on the side surface22cof the unit base member22contains the curable material such as the UV-curable resin or the thermosetting resin, but the invention is not limited thereto. Various types of fluid bodies can be used as the coating liquid27for formation of the reinforcing portion26as long as they have a predetermined liquidity at the time of being applied on the side surface22cof the unit base member22, and thereafter, are curable. For example, a fluid body including a resin material in the state of being melted by heat may be used as the coating liquid27. In this case, the coating liquid27becomes hard as the coating liquid27is solidified as being cooled after the coating liquid27is applied on the side surface22cof the unit base member22. Accordingly, it is possible to obtain the reinforcing portion26containing the resin material. In this manner, the “curing” is a concept that includes not only a phenomenon in which a resin material is cured by heating, the ultraviolet irradiation or the like, but also a phenomenon in which a resin material is cured as being cooled and solidified in the present embodiment. Incidentally, the resin material may be cooled and solidified by natural cooling, or the resin material may be cooled and solidified by forced cooling. In addition, the “solidification” means that a substance is changed from the state of gas or liquid into the state of solid.

(Modified Example of Application Range of Coating Liquid)

In addition, in the above-described present embodiment, the example has been illustrated in which the space surrounded by the side surface22cof the unit base member22, the first protective film81, and the second protective film82is filled with the coating liquid27until the surface of the coating liquid27matches the end surface81cof the first protective film81and the end surface82cof the second protective film82or is positioned on the outer side than the end surfaces81cand82c, but the invention is not limited thereto. For example, the coating liquid27may be applied into the space surrounded by the side surface22cof the unit base member22, the first protective film81, and the second protective film82such that the surface thereof is positioned at the inner side than the end surface81cof the first protective film81and the end surface82cof the second protective film82in the coating step as illustrated inFIG. 16A. In this case, the edge26aeand the edge26beof the reinforcing portion26, which are formed from the coating liquid27, are positioned at the inner side (the unit base member22side) than the end surface81cof the first protective film81and the end surface82cof the second protective film82as illustrated inFIG. 16B.

Even in the present modified example, the first surface22aof the unit base member22and the first surface26aof the reinforcing portion26are positioned on the same plane. In the same manner, the second surface22bof the unit base member22and the second surface26bof26are positioned on the same plane. That is, a difference in level is completely or almost not present between the unit base member22and the reinforcing portion26. Thus, it is possible to suppress a boundary between the unit base member22and the reinforcing portion26from being visually recognized by the observer. Accordingly, it is possible to secure both the strength of the side surface20cof the cover glass20and the design effect of the cover glass20according to the reinforcing portion26of the present embodiment. In addition, the feeling of operating the touch panel is not inhibited by the difference in level.

In addition, the coating liquid27for formation of the reinforcing portion26is applied into the space surrounded by the side surface22cof the unit base member22, the first protective film81, and the second protective film82even in the present modified example. Here, an interval between the first protective film81and the second protective film82is constant. Accordingly, a position of the surface of the coating liquid27to be applied into a space surrounded by the first protective film81and the second protective film82, and further, positions of the side surface26c, the edge26aeand the edge26beof the reinforcing portion26are uniquely set depending on an application amount of the coating liquid27. Thus, it is possible to precisely set the positions of the side surface26cand the edges26aeand26beof the reinforcing portion26by appropriately adjusting the application amount of the coating liquid27to be applied into the space surrounded by the first protective film81and the second protective film82. That is, it is possible to provide the cover glass20which is provided with the side surface20cformed at the high external dimensional accuracy.

(Example Relating to Disposition of Reinforcing Portion)

A specific disposition of the reinforcing portion26is not particularly limited as long as the reinforcing portion26is formed on the side surface22cof the unit base member22. Hereinafter, an example of disposition of the reinforcing portion26will be described with reference toFIGS. 17 to 19.FIGS. 17 to 19illustrate plan views of the cover glass20. Here, a description will be given regarding a case in which the unit base member22of the cover glass20has a rectangular shape when seen in a plan view.

In general, four corners of the cover glass20are parts with highest frequencies of being applied with the impact in the rectangular-shaped cover glass20. On consideration of this point, the reinforcing portion26may be provided in a part including four corners of the unit base member22in the side surface22cof the unit base member22as illustrated inFIG. 17. Incidentally, the four corners of the unit base member22are sharply pointed in the example illustrated inFIG. 17, but the four corners of the unit base member22may be in the state of being chamfered. For example, the four corners of the unit base member22may have angular surfaces or round surfaces.

In addition, the reinforcing portion26may be provided on the side surface22cof the unit base member22such that the unit base member22is surrounded by the reinforcing portion26when seen in a plan view as illustrated inFIG. 18. Accordingly, the cover glass20is capable of withstanding with respect to the impact to be applied from various directions.

Incidentally, the example has been illustrated in which the reinforcing portion26is formed on the side surface22cto form the contour of the unit base member22among side surfaces of the unit base member22in the above-described embodiment and the respective modified examples. However, the reinforcing portion26may be provided on a wall surface23aof a through-hole23when the through-hole23is formed in the unit base member22as illustrated inFIG. 19. That is, a side surface of the unit base member22on which the reinforcing portion26is provided may be the wall surface23aof the through-hole23formed in the unit base member22. The through-hole23is provided to allow a camera, a speaker, or the like, for example, to be mounted to the display device.

FIG. 20is a cross-sectional view illustrating a step of forming the reinforcing portion26on the wall surface23aof the through-hole23illustrated inFIG. 19. Incidentally,FIG. 20illustrates an aspect in which the reinforcing portion26is formed not only on the wall surface23aof the through-hole23, but also on the side surface22cforming the contour of the unit base member22.

In the example illustrated inFIG. 20, the first protective film81and the second protective film82are provided to protrude to the inner side than the wall surface23aof the through-hole23of the unit base member22. Thus, it is possible to form the reinforcing portion26on the wall surface23aat the high dimensional accuracy, as illustrated inFIG. 20, by applying the coating liquid27in a space surrounded by the wall surface23aof the through-hole23of the unit base member22, the first protective film81and the second protective film82

(First Modified Example Relating to Material Forming Reinforcing Portion)

In the above-described present embodiment and the respective modified examples, the reinforcing portion26may be configured to control charging of the cover glass20. For example, the reinforcing portion26may contain a conductive particle. Accordingly, it is possible to suppress the charging of the reinforcing portion26or the unit base member22, and accordingly, it is possible to suppress generation of electrostatic breakdown. Examples of the conductive particle to be added in the reinforcing portion26can include a particle made of carbon black. Preferably, the conductive particle is added such that a surface resistance of the reinforcing portion26is within a range of 105to 108Ω/□.

Incidentally, there is a risk that the reinforcing portion26serves as an antenna when the reinforcing portion26contains the conductive particle in a case in which the unit base member22is surrounded by the reinforcing portion26when seen in a plan view as in a modified example illustrated inFIG. 18. On consideration of this point, the reinforcing portion26may be configured so as not to completely surround the unit base member22when seen in a plan view as illustrated inFIG. 21. Accordingly, it is possible to suppress the reinforcing portion26from serving as the antenna to pick up noise, or serving as a noise source.

(Second Modified Example Relating to Material Forming Reinforcing Portion)

In the above-described present embodiment and the respective modified examples, the reinforcing portion26is formed by curing the coating liquid27. Thus, when a significant shrinkage is caused at the time of curing of the coating liquid27, the accuracy in the dimension of the reinforcing portion26is reduced. In addition, when the significant shrinkage is caused, an adhesion property between the reinforcing portion26and the side surface22cof the unit base member22is also reduced. In addition, when the significant shrinkage is caused in the thickness direction of the unit base member22(the normal direction of the first surface22aand the second surface22bof the unit base member22), a significant difference in level is generated between the first surface22aand the second surface22bof the unit base member22and the first surface26aand the second surface26bof the reinforcing portion26, and as a result, the boundary between the unit base member22and the reinforcing portion26is likely to be visually recognized from the observer. Accordingly, it is preferable to use a material of which shrinkage at the time of being cured is as small as possible as the material to form the coating liquid27or the reinforcing portion26. For example, it is preferable to use a material which is capable of suppressing each difference in level between each of the first surface22aand the second surface22bof the unit base member22and each of the first surface26aand the second surface26bof the reinforcing portion26to be within a range of 1 to 10 μm even when the shrinkage is caused at the time of curing.

Incidentally, the thickness of the compressive stress layer24ais generally set to be within the range of 10 to 100 μm as described above. Therefore, a degree of the shrinkage becomes smaller than the thickness of the compressive stress layer24awhen the material having the small shrinkage at the time of being cured is selected so as to suppress the difference in level between the unit base member22and the reinforcing portion26to be within the range of 1 to 10 μm. Thus, it is possible to prevent the tensile stress layer24bfrom exposing to the side surface20cof the cover glass20even when the coating liquid27or the reinforcing portion26shrinks at the time of curing.

The inventors of the present application have repeated the intensive experiments, and as a result, it was possible to suppress each difference in level between each of the first surface22aand the second surface22bof the unit base member22and each of the first surface26aand the second surface26bof the reinforcing portion26to be within the range of 1 to 10 μm, more particularly, to be approximately 5 μm when a polyene-polythiol-based photocurable resin is used as the material to form the coating liquid27and the reinforcing portion26. Incidentally, a thickness of the unit base member22used in the experiments was 700 μm.

A condition relating to a shrinkage ratio, which is required for the material to form the coating liquid27and the reinforcing portion26, will be examined on the basis of the above-described results of experiments. Here, a shrinkage ratio in the thickness direction of the unit base member22(hereinafter, referred to also as a “thickness direction linear shrinkage ratio”) will be examined. When each difference in level is caused by 10 μm between the first surface22aand the second surface22bof the unit base member22on both the first surface26aside and the second surface26bside of the reinforcing portion26, a thickness direction linear shrinkage ratio at the time of curing of the coating liquid27becomes (10 μm×2/700 μm)×100=2.86%. In addition, when the difference in level is 5 μm, a thickness direction linear shrinkage ratio at the time of curing of the coating liquid27becomes (5 μm×2/700 μm)×100=1.43%. From this point of view, it is possible to say that it is required to use a material having the linear shrinkage ratio of being equal to or lower than 3%, and more preferably, equal to or lower than 1.5% as the material to form the coating liquid27in order to obtain the reinforcing portion26which includes the first surface26aand the second surface26bpositioned on the same plane as the first surface22aand the second surface22bof the unit base member22.

Incidentally, the coating liquid27was in contact with the side surface22cof the unit base member22in the above-described experiments. Thus, it is considered that the side surface22cof the unit base member22exerts a force in a direction to prevent the shrinkage with respect to the coating liquid27which is likely to shrink in the thickness direction of the unit base member22in the vicinity of the side surface22cof the unit base member22. Accordingly, it is considered that a thickness direction linear shrinkage ratio when the coating liquid27, which is in contact with the side surface22c, shrinks in the thickness direction of the unit base member22is smaller than a linear shrinkage ratio in another direction, a linear shrinkage ratio when the coating liquid27, which is not in contact with the side surface22c, shrinks. On consideration of this point, it is considered that it is possible to reliably obtain the reinforcing portion26which includes the first surface26aand the second surface26bpositioned on the same plane as the first surface22aand the second surface22bof the unit base member22in the above-described present embodiment and the respective modified examples when a material having a linear shrinkage ratio of being equal to or lower than 3% in a single body is used. Incidentally, in general, a volume shrinkage ratio is obtained when the linear shrinkage ratio is cubed. Accordingly, a condition that a “linear shrinkage ratio is equal to or lower than 3%, and more preferably, equal to or lower than 1.5%” is converted into a condition that a “volume shrinkage ratio is approximately equal to or lower than 9%, and more preferably, approximately equal to or lower than 4.5%”.

Hereinafter, the above-described polyene-polythiol-based photocurable resin will be described. The polyene-polythiol-based photocurable resin contains an enic compound, a thiol compound and a photopolymerization initiator. Such a polyene-polythiol-based photocurable resin has a smaller curing shrinkage than an acrylic photo-curable resin, and thus, has a high adhesion property with the base member, and further, does not receive the inhibition of polymerization caused by oxygen, which is advantageous.

The enic compound is a polyfunctional compound having two or more carbon-carbon double bonds in a single molecule, and examples thereof include vinyl ethers, vinyl esters, allyl ethers, allyl alcohol derivative, allyl isocyanurate derivative, styrenes, acrylic acid derivative, methacrylic acid derivative, divinylbenzene, and the like. When some of the above-described enic compounds are arranged in descending order in terms of reactivity with the thiol compound, it is arranged such that vinyl ethers, vinyl esters, allyl ethers, allyl isocyanurate derivative, acrylic acid derivative, and styrenes.

The thiol compound is a compound having two or more thiol groups in a single molecule, and examples thereof include esters with mercaptocarboxylic acid and polyhydric alcohol, aliphatic polythiols, aromatic polythiols, and other polythiols. One or two or more types thereof can be used.

Examples of the mercaptocarboxylic acid in the esters with the mercaptocarboxylic acid and the polyhydric alcohol described above include thioglycolic acid, α-mercaptopropionic acid, β-mercaptopropionic acid and the like.

A blending ratio between the enic compound (a) and the thiol compound (b) is preferably set such that a ratio between the number of unsaturated bonds in the enic compound (a) and the number of thiol groups in the thiol compound (b) is within a range of 2:1 to 1:2. When the thiol groups are many exceeding the ratio of 1:2, a lot of unreacted thiol groups remain in the composition after curing reaction, which is not preferable. When the thiol groups are smaller than the ratio of 2:1, it is not preferable in terms that the effect of the high adhesion property or the advantage of not receiving the inhibition of polymerization caused by the oxygen is reduced.

The photopolymerization initiator is not particularly limited, and a known photopolymerization initiator can be used. To be specific, for example, it is possible to use acetophenones (for example, 1-hiydroxy-cyclohexyl-phenyl-ketone which is commercially available as Product name: Irgacure 184 (manufactured by Ciba Specialty Chemicals Co.), benzophenones, thioxanthones, propiophenones, benzyls, acylphosphine oxides, benzoin, benzoin methyl ether or the like, alone or as a mixture thereof as the photopolymerization initiator in the case of resin having a radical-polymerizable unsaturated group.

It is preferable that the above-described photopolymerization initiator (c) is added at a proportion of 0.001 to 10 mass % with respect to the total amount of the above-described enic compound (a) and thiol compound (b). When the proportion is lower than 0.001 mass %, there is a risk of generating a problem that it is difficult to cause a sufficient photopolymerization reaction. In addition, even when the photopolymerization initiator is added to exceed the proportion of 10 mass %, the improvement of the effect is not confirmed.

Besides, it is considered to add filler in the material to form the coating liquid27and the reinforcing portion26in order to reduce the shrinkage at the time of curing. The filler has a smaller degree of shrinkage caused by heat as compared to the resin material, it is possible to reduce the entire degree of shrinkage when the coating liquid27is cured to become the reinforcing portion26by adding the filler. Examples of the filler can include a particle such as carbon black. Incidentally, when the filler is added, the polymerization reaction of the photocurable resin is interfered as light is blocked by the filler, and thus, it is considered that the curing does not sufficiently proceed. On consideration of such a problem, a thermosetting resin may be further added in the material to form the coating liquid27and the reinforcing portion26.

(Example Relating to Shape of Side Surface of Reinforcing Portion)

In the above-described present embodiment and the respective modified examples, the shape of the side surface26c, that is, the shape of the side surface20cof the cover glass20may be trimmed by processing the side surface26cof the reinforcing portion26after obtaining the reinforcing portion26by curing the coating liquid27. As described above, the reinforcing portion26includes the resin material, and thus, it is easy to process the side surface20cof the cover glass20and obtain a desired shape as compared to a case in which the side surface20cof the cover glass20is made of a tempered glass. In addition, the reduction in strength or generation of microcracks due to the processing is hardly generated. It is possible to employ processing using a polishing machine, for example, as the processing method.

For example, the side surface26cof the reinforcing portion26may be processed such that both the edge26aeon the first surface26aside and the edge26beon the second surface26bside of the reinforcing portion26are scraped off as illustrated inFIG. 22A. In the example illustrated inFIG. 22A, both a part intersecting with the first surface26aand a part intersecting with the second surface26b, in the side surface26cof the reinforcing portion26, are processed to have a round surface. Even in this case, it is possible to secure the high external dimensional accuracy in the cover glass20based on the above-described coating method using the protective films81and82when at least a part of a portion which is not processed (hereinafter, referred to also as an unprocessed portion26d) remains on the side surface22c. Incidentally,FIG. 22Aillustrates the example in which the side surface26cis processed such that the side surface26chas the round surface, but the invention is not limited thereto, and the side surface26cmay be processed such that the side surface26chas an angular surface although not illustrated.

Besides, the side surface26cof the reinforcing portion26may be processed such that one of the edge26aeon the first surface26aside and the edge26beon the second surface26bside of the reinforcing portion26, for example, the edge26aeon the first surface26aside is at least scraped off as illustrated inFIG. 22B. In the example illustrated inFIG. 22B, the part intersecting with the first surface26ain the side surface26cof the reinforcing portion26is processed to have the round surface. In this case, the edge26beon the second surface26bside may remain as the unprocessed portion26d. According to the example illustrated inFIG. 22B, it is possible to give an impression that the first surface20aside of the cover glass20is rounded over a wide region by mainly processing the first surface26aside of the reinforcing portion26.

(Modified Example Relating to Position of End Surface of Protective Film)

In the above-described present embodiment and the respective modified examples, the example has been illustrated in which the position of the end surface81cof the first protective film81and the position of the end surface82cof the second protective film82match each other when seen along the normal direction of the base member30or the unit base member22, but the invention is not limited thereto. For example, the end surface81cof the first protective film81provided on the first surface30amay be positioned at the inner side than the end surface82cof the second protective film82provided on the second surface30bas illustrated inFIG. 23A. As a result, the clearance between the first protective films81is larger than the clearance between the second protective films82.

When the base member30is wet etched using the first protective film81and the second protective film82illustrated inFIG. 23Aas the resist, the etching proceeds at higher speed on the first surface30aside than on the second surface30bside since the clearance between the protective films is larger on the first surface30aside. As a result, the edge22aeof the first surface22aof the unit base member22is positioned at the inner side than the edge22beof the second surface22bin the unit laminated body35obtained through the cutting step using the wet etching as illustrated inFIG. 23B. In addition, the position at which the first side surface22don the first surface22aside and the second side surface22eon the second surface22bside are merged becomes a position deviated to the second surface22bInstead of the middle position between the first surface22aand the second surface22b.

FIG. 23Cillustrates the reinforcing portion26which is formed by applying the coating liquid27in the space surrounded by the side surface22cof the unit base member22of the unit laminated body35, illustrated inFIG. 23B, the first protective film81, and the second protective film82, and curing the coating liquid27. Here, the example is illustrated in which the reinforcing portion26is formed such that the edge26aeof the first surface26aof the reinforcing portion26matches the end surface81cof the first protective film81, and the edge26beof the second surface26bof the reinforcing portion26matches the end surface82cof the second protective film82. Since the end surface81cof the first protective film81is positioned at the inner side than the end surface82cof the second protective film82as described above, the edge26aeof the reinforcing portion26is positioned at the inner side than the edge26beof the reinforcing portion26.

FIG. 23Dillustrates the cover glass20, which is obtained by processing the side surface26cof the reinforcing portion26of the cover glass20illustrated inFIG. 23C. Here, the example in which the first surface26aside of the reinforcing portion26is mainly processed is illustrated similarly to the case of the above-described example illustrated inFIG. 22B. Here, the edge26aeof the first surface26aof the reinforcing portion26is positioned at the inner side than the edge26beof the second surface26bin the present modified example as described above, and thus, it is possible to more easily obtain the reinforcing portion26having a shape in which the first surface26ais rounded.

(Modified Example of Cutting Method)

Although the method of cutting the base member30using the wet etching has been described in the above-described present embodiment, the cutting method is not particularly limited. For example, the base member30may be cut using laser. In addition, the base member30may be cut with a scribe line as an origin by forming the scribe line on a surface of the base member30with a cutter or laser, and thereafter, applying a striking force or a bending stress to the base member30.

Incidentally, there is a case in which a microcrack is generated around the scribe line in the case of forming the scribe line on the surface of the base member30. On the contrary, such a microcrack is not generated in the case of cutting the base member30using the wet etching, and from this point, the wet etching is more excellent than the cutting method using the scribe line. Incidentally, the side surface22cof the unit base member22and surroundings thereof may be wet etched in order to remove the microcrack generated around the scribe line after cutting the base member30with the scribe line as the origin.

In the above-described present embodiment, the example has been illustrated in which the protective films81and82are configured by pasting the sheet of the biaxially-oriented polypropylene or the unstretched polypropylene to the base member30via the adhesive layer. However, the method of forming the protective films81and82is not particularly limited as long as the protective film can serve as a frame at the time of generating the reinforcing portion26. For example, the protective films81and82can be provided on the base member30by pasting the photosensitive resist film on each of the first surface30aand the second surface30bof the base member30, then, irradiating the photosensitive resist film with light such as the ultraviolet ray using a photomask or the like according to a desired shape, and performing patterning with a developing solution such as an acid liquid, an alkaline liquid, or an organic solvent.

In the present modified example, the external dimensional accuracy of the end surfaces81cand82cof the protective films81and82conforms to the resolution accuracy of the photosensitive resist film for formation of the protective films81and82. Accordingly, it is possible to accurately set the positions of the edges26aeand26beof the reinforcing portion26, that is, the position of the edge of the cover glass20even in the present modified example.

In addition, the example in which a so-called diamond pattern is employed as patterns of the sensor electrodes41and42of the touch panel sensor unit40has been illustrated in the above-described present embodiment, but the patterns of the sensor electrodes41and42are not limited thereto. It is possible to employ the sensor electrodes41and42having various types of patterns as long as it is possible to detect a touch position with a desired sensitivity or resolution.

In addition, the example in which the transparent conductive material is used to form the sensor electrodes41and42of the touch panel sensor unit40so as to have the translucency has been illustrated in the above-described present embodiment, but the material of the sensor electrodes41and42is not limited thereto. For example, it is also possible to employ a so-called mesh sensor type which is made of a thin metal wire obtained by disposing a non-transparent conductive material such as a silver alloy or copper in a mesh shape as the sensor electrodes41and42.

Incidentally, although several modified examples with respect to the above-described embodiment have been described, it is obvious that a plurality of modified examples can be combined appropriately, and applied.

EXAMPLES

Next, the present invention will be described more in detail using examples, but the present invention is not limited to the description of the following examples as long as it does not exceed a gist thereof.

The cover glass20, which includes the unit base member22and the reinforcing portion26provided on the side surface22cof the unit base member22, was prepared. A unit base member in which the compressive stress layer24ais formed at the first surface22aand the second surface22b, but the compressive stress layer24ais not formed at the side surface22cwas used as the unit base member22. A thickness of the unit base member22was 0.7 mm. An acrylic resin-based photocurable resin was used as the material to form the reinforcing portion26. To be specific, Photolec A-704 manufactured by SEKISUI CHEMICAL CO., LTD. was used. A viscosity of the coating liquid containing the photocurable resin used to be applied on the first surface26awas adjusted to 1500 mPa·s.

A bending strength of the cover glass20thus manufactured was measured. A four-point bending test method was employed as a measuring method. A combination of a tension/compression tester (for example, AG-I manufactured by SHIMADZU CORPORATION) and a four-point bending test jig manufactured for the four-point bending test was used as the measurement device. The used measurement device is illustrated inFIG. 24. As illustrated inFIG. 24, the measurement device includes a pair of indenters91to press the cover glass20from one side of the cover glass20, and a pair of supports92to support the cover glass20on the other side of the cover glass20. Rod-like indenter and support extending along the cover glass20were used as the indenter91and the support92although not illustrated inFIG. 24. Each length of the indenter91and the support92in the depth direction of the paper plane ofFIG. 24was approximately 15 cm. In addition, a distance L′ between the pair of indenters91was 10 mm, and a distance L between the pair of supports92was 30 mm. In addition, a radius R1of each tip of the pair of indenters91was 2.0 mm, and a radius R2of each tip of the pair of supports92was 3.0 mm. In addition, a width I of the cover glass20as an object to be measured was approximately 14 cm, a dimension of the cover glass20in the depth direction of the paper plane ofFIG. 24was approximately 7 cm, and a thickness of the cover glass20was 0.7 mm. Incidentally, positioning of the cover glass20as the object to be measured, the indenter91, and the support92was performed with the eyes such that the respective centers thereof match each other.

In the step of measuring the bending strength, the pair of indenters91was dropped at indenter displacement speed of 7 mm/mm by applying a load F to the pair of indenters91(a load to be applied to the single inner indenter91is F/2). Further, the load F at a point in time at which the cover glass20was broken was set as a strength of the cover glass20. As a result, a bending strength of the cover glass20according to Example 1 was 1250 MPa. In addition, a scratch such as a crack was not generated on the side surface20cof the cover glass20in a post-process in which printing or the like is performed with respect to the cover glass20. In addition, when the side surface20cof the cover glass20was shaved using a sandpaper, only the reinforcing portion26was shaved, and the scratch such as the crack was not generated.

Incidentally, the element portion70including the decorative portion60, the touch panel sensor unit40and the like was provided on the first surface20aof the cover glass20at the time of measuring the bending strength. In addition, an overcoat layer to cover the decorative portion60and the touch panel sensor unit40was also present.

A cover glass which has the same configuration as the case of Example 1 except that the reinforcing portion26was not provided was prepared. A bending strength of this cover glass was measured in the same manner as the case of Example 1. As a result, the bending strength was 750 MPa.

REFERENCE SIGNS LIST