JP2014207537A - Substrate for portable electronic apparatus and portable electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a break and a crack, etc. in a substrate for a portable electronic apparatus.SOLUTION: A substrate for a portable electronic apparatus is arranged in at least a part of an outer package of the portable electronic apparatus and is made of sapphire single crystal. The substrate for the portable electronic apparatus includes: a first main surface that is long in one direction; and a second main surface that is positioned on the opposite side of the first main surface and is long in the one direction. The first main surface and the second main surface are in parallel with an a-surface of the sapphire single crystal and also a direction in the one direction is in parallel with the c-axis of the sapphire single crystal.

Description

  The present invention relates to a portable electronic device substrate disposed on at least a part of an exterior of a portable electronic device, and a portable electronic device.

  2. Description of the Related Art Conventionally, portable electronic devices such as digital cameras and mobile phones that incorporate image display devices such as so-called liquid crystal panels and organic EL panels have been used. In recent years, portable electronic devices referred to as so-called smartphone terminals and tablet terminals that display a relatively large image and include an input device such as a touch panel have been rapidly spreading.

  In these portable electronic devices, a substrate for protecting an image display device such as a liquid crystal panel or an organic EL panel incorporated in the portable electronic device is disposed and used in a part of the exterior of the portable electronic device. ing.

  Among these substrates, in particular, a so-called tempered glass made of aminosilicate glass or the like is mainly used for a transparent substrate that protects the image display surface of the image display device. When a strong external force is applied, cracks and cracks may occur. For example, Patent Document 1 below proposes using a substrate made of a sapphire single crystal as a substrate for a portable electronic device in order to suppress cracking or cracking of the transparent substrate when an external force is applied.

JP 09-8690 A

  Patent Document 1 exemplifies a conventional mobile phone including a relatively small image display device and operation buttons for displaying text data and the like as a portable electronic device. A substrate for a portable electronic device used in a conventional cellular phone as exemplified in Patent Document 1 has a maximum side length of less than about 5 cm and a relatively small area.

  On the other hand, smart phone terminals and tablet terminals that have been rapidly spreading in recent years are required to display relatively large images, but are also required to be as thin as possible. Accordingly, a substrate for a portable electronic device such as a transparent substrate for protecting an image display device is also required to be thin and have a large area. That is, the board | substrate for portable electronic devices used for the smart phone terminal, tablet terminal, etc. which are spreading rapidly in recent years is a shape (area is large and thin shape) which is easy to break compared with the past. For this reason, it has become impossible to sufficiently suppress the occurrence of cracks, cracks, and the like by simply using a sapphire single crystal as a substrate for a portable electronic device used for a smartphone terminal, a tablet terminal, or the like.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a portable electronic device substrate and a portable electronic device that are less likely to be cracked or cracked.

  In order to solve the above-described problems, the present invention provides a portable electronic device substrate made of a sapphire single crystal, which is disposed on a part of an exterior of a portable electronic device, and has a first main surface that is long in one direction. And a second main surface that is long in the one direction and located on the opposite side of the first main surface, and the first main surface and the second main surface are parallel to the a-plane of the sapphire single crystal. And a direction along the one direction is parallel to the c-axis of the sapphire single crystal. An image display device protected by the portable electronic device substrate, comprising the portable electronic device substrate; and an image display surface facing the first main surface of the portable electronic device substrate; There is also provided a portable electronic device comprising a case member for holding the portable electronic device substrate on which the portable electronic device substrate is disposed.

  A portable electronic device substrate made of a sapphire single crystal disposed in a part of an exterior of the portable electronic device, the first main surface being long along one direction and opposite to the first main surface A second main surface that is long along the one direction located on the side, and the first main surface and the second main surface are parallel to the r-plane of the sapphire single crystal and along the one direction. Provided is a substrate for portable electronic equipment, characterized in that the direction is orthogonal to the a-axis of the sapphire single crystal. An image display device protected by the portable electronic device substrate, comprising the portable electronic device substrate; and an image display surface facing the first main surface of the portable electronic device substrate; There is also provided a portable electronic device comprising a case member for holding the portable electronic device substrate on which the portable electronic device substrate is disposed.

  In the first aspect of the substrate for a portable electronic device according to the present invention, the first main surface and the second main surface are long in one direction, and the first main surface and the second main surface are sapphire single crystals. Since this one direction (long side direction) is parallel to the c-axis of the sapphire single crystal, the resistance along the direction in which bending easily occurs when an external force is applied to the portable electronic device substrate. The folding strength is particularly strong, and cracks and cracks in the portable electronic device substrate can be sufficiently suppressed.

  Moreover, in the 2nd aspect of the board | substrate for portable electronic devices which concerns on this invention, a 1st main surface and a 2nd main surface are long shapes along one direction, and a 1st main surface and a 2nd main surface are sapphire. Since the direction parallel to the r-plane of the single crystal and along one direction (long side direction) is orthogonal to the a-axis of the sapphire single crystal, it is easy to bend when an external force is applied to the portable electronic device substrate. The bending strength along the line is particularly strong, and cracks and cracks in the substrate for portable electronic devices can be sufficiently suppressed.

It is a schematic perspective view of the 1st embodiment of the board | substrate for portable electronic devices of this invention. It is a figure explaining the smart phone terminal which is one of the embodiment of the portable electronic device of this invention provided with the board | substrate for portable electronic devices shown in FIG. 1, (a) is a schematic perspective view, (b) is schematic. It is sectional drawing. It is a figure which shows the operation state of the smart phone terminal shown in FIG. It is the figure which showed an example of the mode of a deformation | transformation of a smart phone terminal and a board | substrate for portable electronic devices when external force is added to the smart phone terminal shown in FIG. 2, (a) is a schematic perspective view of a smart phone terminal, b) is a cross-sectional view taken along the long side direction of the portable electronic device substrate, and (c) is a cross-sectional view taken along the short side direction of the portable electronic device substrate. (A) is a perspective view of a model of a portable electronic device substrate, and (b) and (c) are obtained when an external force is applied to the portable electronic device substrate in the state shown in (a). It is a figure which shows the deformation | transformation state of the board | substrate for portable electronic devices, (b) is sectional drawing along the long side direction of the board | substrate for portable electronic devices shown to (a), (c) is (a). It is sectional drawing along the short side direction of the board | substrate for portable electronic devices shown. It is a schematic perspective view of the 2nd embodiment of the board | substrate for portable electronic devices of this invention. It is a figure explaining the tablet terminal which is one of the embodiment of the portable electronic device of this invention provided with the board | substrate for portable electronic devices shown in FIG. 6, (a) is a schematic perspective view, (b) is schematic. It is sectional drawing. It is the figure which showed an example of the deformation | transformation state of a tablet terminal and a board | substrate for portable electronic devices when external force is added to the tablet terminal shown in FIG. 7, (a) is a schematic perspective view of a tablet terminal, b) is a cross-sectional view taken along the long side direction of the portable electronic device substrate, and (c) is a cross-sectional view taken along the short side direction of the portable electronic device substrate. (A) is a perspective view of a model of a portable electronic device substrate, and (b) and (c) are obtained when an external force is applied to the portable electronic device substrate in the state shown in (a). It is a figure which shows the deformation | transformation state of a board | substrate for portable electronic devices, (b) is sectional drawing along the long side direction of the transparent substrate shown to (a), (c) is a transparent substrate shown to (a). It is sectional drawing along a short side direction. It is a figure explaining the smart phone terminal of other embodiment of the portable electronic device of this invention, (a) is a schematic perspective view, (b) is a schematic sectional drawing.

  The board | substrate for portable electronic devices of this invention and a portable electronic device are demonstrated with reference to drawings. FIG. 1 is a schematic perspective view of a portable electronic device substrate 10 (hereinafter also simply referred to as a transparent substrate 10), which is one of the first embodiments of the portable electronic device substrate of the present invention. Moreover, FIG. 2 is a figure explaining the smart phone terminal 1 which is one of Embodiment of the portable electronic device of this invention provided with the transparent substrate 10 shown in FIG. FIG. 2B is a schematic perspective view, and FIG. 2B is a schematic cross-sectional view of the smartphone terminal 1.

The transparent substrate 10 is a transparent substrate made of a sapphire single crystal arranged in a part of the exterior of the smartphone terminal 1, and is in one direction (a direction along the arrow L shown in FIG. 1. The first main surface 10A and the second main surface 10A and the second main surface 10B are long along the long side direction located on the opposite side of the first main surface 10A. The surface 10B is parallel to the a-plane of the sapphire single crystal and the long side direction is parallel to the c-axis of the sapphire single crystal. As shown in FIG. 1, the four corners of the transparent substrate 10 are rounded. A sapphire single crystal refers to a single crystal of alumina (Al ₂ O ₃ ), and in this specification refers to a single crystal having an Al ₂ O ₃ purity of about 90% or more. It is preferable that the Al ₂ O ₃ purity is 99% or more from the standpoint that scratches are less prone and cracks and chips are more reliably suppressed.

  The smartphone terminal 1 includes a case member 21 that holds the transparent substrate 10 and an image display device 22 that is protected by the transparent substrate 10 and includes an image display surface 22A that faces the first main surface 10A of the transparent substrate 10. The smartphone terminal 1 also includes a transparent reinforcing substrate 26 mainly composed of tempered glass made of, for example, aminosilicate glass, which is bonded to the first main surface 10A of the transparent substrate 10, and the first main surface 10A is the reinforcing substrate. 26 faces the image display surface 22A. One main surface of the reinforcing substrate 26 is joined to the first main surface 10A of the transparent substrate 10 via, for example, an adhesive. The reinforcing substrate 26 is bonded to the case member 21 at a part of the peripheral portion of the main surface opposite to the side surface bonded to the first main surface 10A via a bonding layer 27 containing epoxy resin as a main component. The case body 21 holds the reinforcing substrate 26. The thickness of the transparent substrate 10 is about 0.1 to 1 mm, for example, and the thickness of the reinforcing substrate 26 is about 0.3 to 1.5 mm, for example.

  The case member 21 is made of, for example, fiber reinforced plastic, and the case member 21, the transparent substrate 10, and the reinforcing substrate 26 constitute the exterior body 20. The image display device 22 is an image display device including a liquid crystal display panel and a light source device (not shown), and is arranged in the interior of the exterior body 70, that is, in the internal space surrounded by the exterior body 20. The smartphone terminal 1 also includes a touch input device 24 and a control unit 28 connected to the image display device 22 and the touch input device 24.

The touch input device 24 includes a transparent electrode 29 formed on the main surface of the reinforcing substrate 26 (the main surface opposite to the side surface joined to the first main surface 10A), a transparent insulating layer (not shown), and the like. For example, a so-called capacitive touch input device, in which the second main surface 10B of the transparent substrate 10 is used as an input surface, and the position of an operator's finger touching the second main surface 10B can be detected. it can. The second main surface 10B of the transparent substrate 10 is a surface of a sapphire single crystal (specifically, a surface parallel to the a-plane of the sapphire single crystal), and is less likely to be scratched than tempered glass made of aminosilicate glass or the like. In the smartphone terminal 1, since the reinforcing substrate 26 is bonded to the transparent substrate 10, for example, even when the smartphone terminal 1 is dropped and a large impact is applied to the transparent substrate 10, the image display device 22 can be obtained using only the transparent substrate 10. As compared with the case of protecting the substrate, the transparent substrate 10 is less likely to be cracked or chipped.

  The control unit 28 includes a semiconductor element and an electric circuit (not shown), and is connected to the image display device 22 and the touch input device 24. The control unit 28 receives a signal (such as information indicating the position of the operator's finger) from the touch input device 24 and controls an image to be displayed on the image display surface 22A of the image display device 22 according to the received information. .

  In addition, in the exterior body 20 of the smartphone terminal 1, for example, a transceiver (not shown) provided with an antenna, a microphone device (not shown) that converts the voice of the operator of the smartphone terminal 1 into an electrical signal, and a radio signal received by the transceiver A plurality of devices (not shown) such as a speaker device (not shown) for reproducing and outputting the corresponding sound in real time are arranged. The control unit 28 is also connected to these devices (not shown), and the control unit 28 controls the operation of these devices (not shown).

FIG. 3 is a diagram illustrating an operation state of the smartphone terminal 1 illustrated in FIG. 2. As shown in FIG. 3, the operator holds the smartphone terminal 1 with one hand 31 and touches the second main surface 10 </ b> B of the transparent substrate 10 with the finger of the other hand 32. The smartphone terminal 1 has a relatively short length of about 6 cm in the short side direction (the direction along the arrow S shown in FIG. 3) perpendicular to the long side direction so that it can be easily held by the palm of one hand 31. ing. On the other hand, when the operator touches his / her ear so that the image displayed on the image display surface 22A of the image display device 22 is enlarged to some extent so that the operator can visually recognize it through the transparent substrate 10, The length along the long side direction (the direction along the arrow L shown in FIG. 3) of the smartphone terminal 1 is set to a certain length of about 12 cm so that the voice coming out from the mouth can be received sufficiently. Thus, in the smart phone terminal 1, the ratio of the length along the long side direction to the length along the short side direction (hereinafter also referred to as the aspect ratio of the terminal) is a rectangular shape having a length of about 2.0. . Transparent substrate 10 also, for example, the long side direction to a length along l _1, long if the edge direction short side direction orthogonal to the length and the s _1, in the short side direction length s ₁ for the long side direction of the The ratio of the length l ₁ (hereinafter also referred to as the aspect ratio of the transparent substrate), that is, the value of l ₁ / s ₁ is about 1.7 to 2.5, preferably about 2.0. In addition, when surveying 50 types of smartphone terminals that were or were scheduled to be released in Japan from September 2012 to March 2013, the average aspect ratio of the terminals was 2.00 and the minimum was 1 .86, the maximum is 2.13, and the aspect ratio of a transparent substrate of a smartphone terminal that is generally popular is about 2.0.

  FIG. 4 is a diagram illustrating an example of a state of deformation of the smartphone terminal 1 and the transparent substrate 10 when an external force is applied to the smartphone terminal 1, and FIG. 4A is a schematic perspective view of the smartphone terminal 1. 4B is a cross-sectional view taken along the long side direction of the transparent substrate 10, and FIG. 4C is a cross-sectional view taken along the short side direction of the transparent substrate 10. As described above, the exterior body 20 of the smartphone terminal 1 includes the transparent substrate 10 made of sapphire single crystal, the reinforcing substrate 26, and the case body 21. Since the transparent substrate 10 is harder than the case body 21 and the reinforcing substrate 26 and is hard to bend, the case where the transparent substrate 10 hardly bends and follows the deformation of the transparent substrate 10 when an external force is applied to the smartphone terminal 1. The body 21 is deformed.

  The smart phone terminal 1 is often carried by being worn on the operator's body, for example, carried in a pants pocket. When carrying such a smartphone terminal 1, for example, the smartphone terminal 1 often sits on a chair with the smartphone terminal 1 in a pants pocket. In such a case, pressure is mainly applied to the central portion of the transparent substrate 10, and the transparent substrate 10 is easily deformed so as to be bent along the long side direction.

  For example, consider a simple model in which the transparent substrate 10 is supported by support members 40 arranged in regions corresponding to the four corners of the first main surface 10A as shown in FIG. The model shown in FIG. 5A is a model in which the support member 40 is disposed on the first main surface 10A side of the transparent substrate 10. 5 (b) and 5 (c) are diagrams showing a deformation state of the transparent substrate 10 when an external force is applied to the transparent substrate 10 in the state shown in FIG. 5 (a), and FIG. 10 is a cross-sectional view along the long side direction (direction along the arrow L shown in FIG. 5A), and FIG. 5C is the short side direction of the transparent substrate 10 (arrow shown in FIG. 5C). It is sectional drawing along the direction along S).

  In the state shown in FIG. 5A, a concentrated load is applied to the position P of the second main surface 10B corresponding to the center position of the transparent substrate 10 as shown by the arrows in FIGS. 5B and 5C. In this case, it is easy to be deformed so as to bend along the long side direction as shown in FIG. Once the deformation starts to bend along the long side direction, the cross-sectional secondary moment with respect to the bending deformation along the short side direction increases. In other words, the more the deformation along the long side proceeds, the less the bending along the short side occurs. That is, in the model shown in FIG. 5A, when a load is applied to the position P, it is deformed so as to be bent intensively along the long side direction and hardly bent along the short side direction. Go. In FIG. 5, only an example of the deformation state of the transparent substrate 10 in the smartphone terminal 1 is shown, but the aspect ratio of the main surface as used in the smartphone terminal 1 is relatively large as about 1.75 to 2.5. The transparent substrate 10 is easy to bend along the long side direction L as in the example shown in FIG.

  In the present embodiment, the first main surface 10A and the second main surface 10B of the transparent substrate 10 are parallel to the a-plane of the sapphire single crystal, and the long side direction is parallel to the c-axis of the sapphire single crystal. The sapphire single crystal has anisotropy in the crystal structure, and in the case of a sapphire single crystal having a principal plane parallel to the a-plane, the bending strength along the direction parallel to the c-axis of the sapphire single crystal is the c-axis. It is larger than the bending strength along the direction parallel to the m-axis perpendicular to.

  Specifically, the bending strength is a value of three-point bending strength measured by a measuring method based on JIS R1601. The inventor of the present application measured by a measurement method based on JISR1601, the bending strength of the sapphire single crystal when applied with a force to bend along the direction parallel to the c-axis of the sapphire single crystal is about 960 MPa, The bending strength of the sapphire single crystal when a force to bend along the direction parallel to the m-axis of the sapphire single crystal was applied was about 450 MPa. That is, in the smartphone terminal 1, the transparent substrate 10 is arranged with the long side direction parallel to the c-axis of the sapphire single crystal so that the bending strength is higher along the direction in which bending easily occurs when an external force is applied. doing. For this reason, in this embodiment, even when an external force is applied to the smartphone terminal 1, it is difficult for the transparent substrate 10 to be cracked or cracked.

  When the transparent substrate 10 made of sapphire single crystal is used as the transparent substrate of the smartphone terminal 1 and the relationship between the long side direction and short side direction of the transparent substrate 10 and the crystal orientation of the transparent substrate 10 is not particularly set, the transparent substrate The crystal orientation of the sapphire single crystal in the transparent substrate 10 varies with respect to the long side direction and the short side direction of 10. As described above, since the smartphone terminal 1 has a relatively large aspect ratio of about 1.75 to 2.5, when an external force is applied, a force that bends along the long side direction of the transparent substrate is applied. Although it is easy to start, if the relationship between the long side direction and the short side direction of the transparent substrate 10 and the crystal orientation of the transparent substrate 10 is not particularly set, the crystal orientation with respect to the easily bent direction varies for each substrate. The ease of occurrence of cracks and cracks varies for each substrate, and even when a small pressure is applied, cracks and cracks may easily occur. On the other hand, in the transparent substrate 10 and the smartphone terminal 1 of the present embodiment, when the external force is applied to the transparent substrate 10, the bending strength along the direction in which the transparent substrate 10 easily bends is particularly strong. Cracks and the like are sufficiently suppressed.

  FIG. 6 is a schematic perspective view of a portable electronic device substrate 60 (hereinafter also simply referred to as a transparent substrate 60), which is one of the second embodiments of the portable electronic device substrate of the present invention. 7 is a diagram for explaining a tablet terminal 2 that is one of the embodiments of the portable electronic device of the present invention, which includes the transparent substrate 60 shown in FIG. 6, and FIG. 7 (a) is a schematic perspective view, FIG. 7B is a schematic cross-sectional view.

  The transparent substrate 60 is a transparent substrate made of a sapphire single crystal disposed in a part of the exterior of the tablet terminal 2 and is in one direction (the direction indicated by the arrow L ′ shown in FIG. 6, hereinafter referred to as the long side direction). The first main surface 60A and the second main surface have a first main surface 60A that is long along the long side direction and a second main surface 60B that is long along the long side direction located on the opposite side to the first main surface 60A. 60B is parallel to the r-plane of the sapphire single crystal and the long side direction is orthogonal to the a-axis of the sapphire single crystal. As shown in FIG. 6, the four corners of the transparent substrate 60 are rounded.

  The tablet terminal 2 includes a case member 71 that holds the transparent substrate 60 and an image display device 72 that is protected by the transparent substrate 60 and includes an image display surface 72A that faces the first main surface 60A of the transparent substrate 60. The tablet terminal 2 also includes a transparent reinforcing substrate 76 mainly composed of tempered glass made of, for example, aminosilicate glass, which is bonded to the first main surface 60A of the transparent substrate 60, and the first main surface 60A is the reinforcing substrate. It faces the image display surface 72 </ b> A via 76. The reinforcing substrate 76 has one main surface bonded to the first main surface 60A of the transparent substrate 60 via, for example, an adhesive, and is opposite to the side of the reinforcing substrate 76 bonded to the first main surface 60A. A part of the peripheral edge of the main surface on the side is joined to the case member 71 via a joining layer 77 mainly composed of an epoxy resin, for example. The case member 71 is made of, for example, fiber reinforced plastic, and the case member 71, the transparent substrate 60, and the reinforcing substrate 76 constitute an exterior body 70. The thickness of the transparent substrate 60 is about 0.1 to 1 mm, and the thickness of the reinforcing substrate 76 is about 0.3 to 1.5 mm.

  The image display device 72 is a known image display device including a liquid crystal display panel and a light source device (not shown), and is arranged in the exterior body 70, that is, in an internal space surrounded by the transparent substrate 60, the reinforcing substrate 76, and the case body 71. Has been. The tablet terminal 2 also includes a touch input device 74 and a control unit 78 connected to the image display device 72 and the touch input device 74.

  The touch input device 74 includes a transparent electrode 79 formed on the main surface of the reinforcing substrate 76 (the main surface opposite to the side bonded to the first main surface 60A), a transparent insulating layer (not shown), and the like. This is a so-called known capacitive touch input device. The touch input device 74 uses the second main surface 60B of the transparent substrate 60 as an input surface, and can detect the position of the operator's finger touching the second main surface 60B. The second main surface 60B of the transparent substrate 60 is a surface of a sapphire single crystal (specifically, a surface parallel to the r-plane of the sapphire single crystal), and is less likely to be scratched than tempered glass made of aminosilicate glass or the like. In the tablet terminal 2, since the reinforcing substrate 76 is bonded to the transparent substrate 60, for example, even when the tablet terminal 2 is dropped and a large impact is applied to the transparent substrate 60, only the transparent substrate 60 is used as the image display device. Compared with the case where 72 is protected, the transparent substrate 60 is less likely to be cracked or chipped.

  The control unit 78 includes a semiconductor element and an electric circuit (not shown), and is connected to the image display device 72 and the touch input device 74. The control unit 78 receives a signal (such as information indicating the position of the operator's finger) from the touch input device 74 and controls the operation of the image display device 72 according to the received information.

  In the exterior body 70 of the tablet terminal 2, for example, a transceiver (not shown) provided with an antenna, a microphone device (not shown) that converts the voice of the operator of the tablet terminal 2 into an electrical signal, and a radio signal received by the transceiver A plurality of devices (not shown) such as a speaker device (not shown) for reproducing and outputting the corresponding sound in real time are arranged. The control unit 78 is also connected to these devices (not shown), and the control unit 78 controls the operation of these devices (not shown).

The tablet terminal 2 is often carried by a user in a bag or the like, and the overall shape is close to the shape of a general paper standardized by ISO 216 called so-called A4 size paper or B5 size paper. Specifically, in the tablet terminal 2, the long side direction (FIGS. 6 and 7) with respect to the length along the short side direction (direction along the arrow S ′ shown in FIGS. 6 and 7) perpendicular to the long side direction. A length ratio (also referred to as an aspect ratio of the terminal) along the arrow L ′ shown in FIG. For example, when the length of the transparent substrate 60 in the long side direction is l ₂ and the length in the short side direction orthogonal to the long side direction is s ₂ , the length in the long side direction with respect to the length s ₂ in the short side direction the value of l ratio of ₂ (the aspect ratio of the transparent substrate) i.e. _l 2 / _{s 2} is about 1.0 to 1.7, preferably about 1.5. More specifically, in the tablet terminal 2 of the present embodiment, the length s ₂ in the short side direction is about 16 cm, the length l ₂ in the long side direction is about 24 cm, and the aspect ratio l ₂ / s _{2 of the} transparent substrate. Is about 1.5. In addition, when we surveyed 20 types of tablet devices scheduled to be released in Japan from January 2013 to March 2013, the aspect ratio of the devices was 1.52 on average, 1.32 on minimum, and maximum It is 1.60, and it is known that the aspect ratio of a transparent substrate of a tablet terminal that is generally spread is about 1.5.

  FIG. 8 is a diagram illustrating an example of the deformation state of the tablet terminal 2 and the transparent substrate 60 when an external force is applied to the tablet terminal 2, and FIG. 8A is a schematic perspective view of the tablet terminal 2. 8B is a cross-sectional view along the long side direction of the transparent substrate 60, and FIG. 8C is a cross-sectional view along the short side direction of the transparent substrate 60. As described above, the exterior body 70 of the tablet terminal 2 includes the transparent substrate 60 made of sapphire, the reinforcing substrate 76, and the case body 71. Since the transparent substrate 60 is harder and harder to bend than the case body 71 and the reinforcing substrate 76, the transparent substrate 60 is most difficult to bend when an external force is applied to the tablet terminal 2, and follows the deformation of the transparent substrate 60. The case body 71 is deformed.

  The tablet terminal 2 is carried in a bag or the like as described above. For example, a load is applied to the second main surface 60 </ b> B of the transparent substrate 60 when the tablet terminal 2 is in the bag and the bag is pressed from the outside.

  For example, consider a simple model in which the transparent substrate 60 is supported by support members 90 arranged in regions corresponding to the four corners of the first main surface 60A as shown in FIG. The model shown in FIG. 9A is a model in which the support member 90 is arranged on the first main surface 60A side of the transparent substrate 60. 9 (b) and 9 (c) are diagrams showing a deformed state of the transparent substrate 60 when an external force is applied to the transparent substrate 60 in the state shown in FIG. 9 (a). FIG. 9 is a cross-sectional view along the long side direction of the transparent substrate 60 (the direction along the arrow L ′ shown in FIG. 9A), and FIG. 9C is the short side direction of the transparent substrate 60 (FIG. 9C). It is sectional drawing along the direction along arrow S 'shown to).

In the state shown in FIG. 9A, a load is applied to the position Q of the second main surface 60B corresponding to the center position of the transparent substrate 60 as shown by the arrows in FIGS. 9B and 9C. In this case, since the distance between the support member 90 and the position Q along the long side direction is longer than the distance between the support member 60 and the position Q along the short side direction, as shown in FIG. It is easy to be deformed to bend along the side direction. Once the deformation that bends along the long side direction begins, the cross-sectional secondary moment with respect to the bending deformation along the short side direction increases. In other words, when deformed along the long side direction, the shape becomes relatively difficult to bend along the short side direction.

However the tablet computer 2, not so large and the aspect ratio of the transparent substrate 60 is about 1.5, also a 16cm even length of the short side s _2, such as a long side direction of the transparent substrate 60 described above in a tablet terminal 2 Greater than the length l ₂ (12 cm) along That is, in the tablet terminal 2, in addition to being easy to bend in the direction along the long side direction L, it is also relatively easy to bend in the direction along the short side direction S as compared with the case of the tablet terminal 2.

  In the present embodiment, the first main surface 60A and the second main surface 60B of the transparent substrate 60 are parallel to the r-plane of the sapphire single crystal, and the long side direction is orthogonal to the a-axis of the sapphire single crystal. The sapphire single crystal has anisotropy in the crystal structure, and in the case of a sapphire single crystal having a principal plane parallel to the r-plane, the bending strength along the direction perpendicular to the a-axis of the sapphire single crystal is Stronger than the bending strength along the parallel direction. Specifically, in the case of a sapphire single crystal having a principal surface parallel to the r-plane, the bending strength of the sapphire single crystal when a force is applied to bend along a direction perpendicular to the a-axis of the sapphire single crystal is The bending strength of the sapphire single crystal is 480 MPa when a force such as bending along the direction parallel to the a-axis of the sapphire single crystal is applied. In the tablet terminal 2, a crystal orientation having a higher bending strength is arranged along a direction in which the tablet terminal 2 is easily bent when an external force is applied. Even in this embodiment, even when an external force is applied to the tablet terminal 2, it is difficult for the transparent substrate 10 to be cracked or cracked.

  In the tablet terminal 2, since the aspect ratio of the terminal is not so large as about 1.5 as described above, bending along the short side direction is likely to occur compared to the case of the smartphone terminal 1 or the like. For this reason, as the transparent substrate 60 of the tablet terminal 2, it is preferable that the absolute value of the bending strength when a force that bends along the short side direction is applied is larger than that of the smartphone terminal 1, for example. In the present embodiment, as the transparent substrate 60 of the tablet terminal 2, the first main surface 60A and the second main surface 60B are parallel to the r-plane of the sapphire single crystal and the direction along the long side of the rectangular shape is the sapphire single crystal. By using a substrate perpendicular to the a-axis, the absolute value of the bending strength when a force that bends along the long side direction L is applied is relatively small at 580 MPa, but the short side direction S The absolute value of the bending strength when a bending force is applied is relatively large at 480 MPa. In the case of the tablet terminal 2 having a terminal aspect ratio of about 1.5, the load applied to the transparent substrate 60 is not concentrated in the direction of bending in the long side direction but in the direction of bending in the short side direction. Therefore, the absolute value of the bending strength when a force that bends along the long side direction is applied may be about 580 MPa, for example, smaller than that of the smartphone terminal 1.

  On the other hand, in the case of the above-described smartphone terminal 1, the force tends to concentrate so as to bend in the direction along the long side direction. Therefore, the absolute bending strength when a force that bends along the long side direction is applied. A transparent substrate 10 having a sufficiently large value of about 9600 MPa and having a first main surface 10A and a second main surface 10B parallel to the a-plane of the sapphire single crystal and the long side direction parallel to the c-axis of the sapphire single crystal is used. ing.

For example, the ratio of the length in the direction along the long side of the rectangle to the length in the direction along the short side of the rectangle, such as a transparent substrate used for a so-called smartphone terminal that is operated by being held with one hand by the operator, is 1. The transparent substrate having a thickness of from 7 to less than 2.5 is the transparent substrate of the first embodiment, that is, a transparent substrate made of a sapphire single crystal, wherein the first main surface and the second main surface are sapphire single crystals. It is preferable to use a transparent substrate that is parallel to the a-plane and whose long side direction is parallel to the c-axis of the sapphire single crystal.

  Further, the ratio of the length in the direction along the long side of the rectangle to the length in the direction along the short side of the rectangle, such as a transparent substrate used for a so-called tablet terminal, is greater than 1.0. The transparent substrate of less than 7 is the transparent substrate of the second embodiment, that is, a transparent substrate made of a sapphire single crystal, and the first main surface and the second main surface are parallel to the r-plane of the sapphire single crystal. In addition, it is preferable to use a transparent substrate whose long side direction is orthogonal to the a-axis of the sapphire single crystal.

  In the present invention, the inventor of the present application pays attention to the common points and differences in the shape of the portable electronic device in this way, and the present inventor It was made by intensive study.

  FIG. 10 is a diagram for explaining a smartphone terminal 100 which is one embodiment of the portable electronic device of the present invention. FIG. 10 (a) is a schematic perspective view, and FIG. 10 (b) is a schematic cross-sectional view. . The smartphone terminal 100 further includes not only the transparent substrate 111 that protects the image display device 122 but also transparent substrates 112 to 126 made of sapphire single crystal, as a transparent substrate made of sapphire single crystal disposed in a part of the exterior. This is different from the smartphone terminal 1 of the embodiment shown in FIG. The smartphone terminal 100 includes an image display device 22, a touch input device 124, and a control unit 128 connected to the image display device 122 and the touch input device 124.

  The transparent substrate 111 has a first main surface 111A that is long along one direction (long side direction) and a second main surface 111B that is long on the opposite side of the first main surface 111A along the long side direction. The first main surface 111A and the second main surface 111B are parallel to the a-plane of the sapphire single crystal and the long side direction is parallel to the c-axis of the sapphire single crystal. The transparent substrate 112 also has a first main surface 112A that is long along one direction (long side direction) and a second main surface 112B that is long along the long side direction and is located on the opposite side of the first main surface 112A. The first main surface 112A and the second main surface 112B are parallel to the a-plane of the sapphire single crystal and the long side direction is parallel to the c-axis of the sapphire single crystal. Similarly to the transparent substrate 112, the transparent substrate 113 to the transparent substrate 116 also have a first main surface that is long along one direction (long-side direction) and a first long surface along the long-side direction that is located on the opposite side of the first main surface. The first main surface and the second main surface are parallel to the a-plane of the sapphire single crystal, and the long side direction is parallel to the c-axis of the sapphire single crystal.

  Of the transparent substrates 111 to 116, the first main surfaces 111A to 116A facing the image display device 122 side (the first main surface 115A and the first main surface 116A are not shown) are made of aminosilicate glass or the like. Reinforcing substrates 131 to 136, which are tempered glass, are bonded to each other (reinforcing substrates 135 and 136 are not shown).

  In the transparent substrate 111, the first main surface 111 </ b> A is opposed to the image display surface 122 </ b> A through the reinforcing substrate 131. Further, among the reinforcing substrates 131 to 136, colored layers 142 to 146 are attached to inner main surfaces (main surfaces facing the image display device 122) of the reinforcing substrates 132 to 136 excluding the reinforcing substrate 131, respectively. (Colored layers 145 and 146 are not shown). When the smartphone terminal 100 is viewed, the image display surface 122A of the image display device 122 is visually recognized from the second main surface 111B of the transparent substrate 111. However, the second main surfaces 112B to 116B of the transparent substrates 112 to 116 (second Colored layers 142 to 146 are visually recognized from the main surface 115B and the second main surface 116B (not shown).

  The reinforcing substrates 131 to 136 have one main surface bonded to the second main surface of the transparent substrates 111 to 116 via, for example, an adhesive, and bonded to the second main surface of the reinforcing substrates 131 to 136. A part of the peripheral edge portion of the main surface on the opposite side to the existing side is bonded to the case member 121 via a bonding layer 127 whose main component is an epoxy resin. The case member 121 is made of, for example, fiber reinforced plastic, and the case member 121, the transparent substrates 111 to 116, the reinforcing substrates 131 to 136, and the colored layers 142 to 146 constitute an exterior body.

  The smartphone terminal 100 includes not only the transparent substrate 111 for protecting the image display device 122 but also the transparent substrates 112 to 126 arranged on a portion corresponding to a surface other than the surface corresponding to the image display device 122. Therefore, not only one surface corresponding to the image display device 122 but also the entire image display device 122 is hardly scratched, and cracks, chips, and the like are unlikely to occur. In this embodiment, the transparent substrates 111 to 116 made of six sapphire single crystals are arranged on a part of the exterior of the smartphone terminal 100, but the number of transparent substrates made of sapphire single crystals is not particularly limited.

  The substrate for a portable electronic device and the portable electronic device of the present invention are not limited to the above embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

DESCRIPTION OF SYMBOLS 1 Smart phone terminal 2 Tablet terminal 10, 60 Board | substrate for portable electronic devices (transparent substrate)
10A, 60A First main surface 10B, 60B Second main surface 20, 70 Case members 22, 72 Image display devices 22A, 72A Image display surfaces 24, 74 Touch input devices 26, 76 Reinforcing substrates 27, 77 Bonding layers 28, 78 Control unit 40, 90 Support member

Claims (8)

A portable electronic device substrate made of a sapphire single crystal, disposed on at least a part of the exterior of the portable electronic device,
A first main surface long along one direction, and a second main surface long along the one direction located on the opposite side of the first main surface;
The first main surface and the second main surface are parallel to the a-plane of the sapphire single crystal, and the direction along the one direction is parallel to the c-axis of the sapphire single crystal. Equipment substrate.   The portable electronic device according to claim 1, wherein a ratio of a length along the one direction to a length along another direction orthogonal to the one direction is 1.7 or more and less than 2.5. Equipment substrate. The portable electronic device substrate according to claim 1 or 2,
An image display device protected by the portable electronic device substrate, comprising: a case member for holding the portable electronic device substrate; and an image display surface facing the first main surface of the portable electronic device substrate; A portable electronic device comprising:   A transparent reinforcing substrate mainly composed of glass, which is bonded to the first main surface of the portable electronic device substrate, is provided, and the first main surface faces the image display surface through the reinforcing substrate. The portable electronic device according to claim 3, wherein A portable electronic device substrate made of a sapphire single crystal, disposed on at least a part of the exterior of the portable electronic device,
A first main surface long along one direction, and a second main surface long along the one direction located on the opposite side of the first main surface;
The first main surface and the second main surface are parallel to the r-plane of the sapphire single crystal, and the direction along the one direction is perpendicular to the a-axis of the sapphire single crystal. Substrate.   6. The portable electronic device substrate according to claim 5, wherein a ratio of lengths in a direction along another direction orthogonal to the one direction is greater than 1.0 and less than 1.7. A substrate for a portable electronic device according to claim 5 or 6,
A case member for holding the portable electronic device substrate;
A portable electronic device comprising: an image display device protected by the portable electronic device substrate having an image display surface facing the first main surface of the portable electronic device substrate.   A transparent reinforcing substrate mainly composed of glass, which is bonded to the first main surface of the portable electronic device substrate, is provided, and the first main surface faces the image display surface through the reinforcing substrate. The portable electronic device according to claim 7, wherein

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