JP2005332919A - Digital apparatus casing and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To give a stereoscopic shape by heating and molding a sheet-like laminate which is configured by laminating a synthetic resin layer and an electromagnetic wave shield layer. <P>SOLUTION: A digital apparatus casing has a laminated structure of an inner layer 4 and a top layer 3. The inner layer 4 includes at least an electromagnetic wave shield layer 5. The electromagnetic wave shield layer 5 is a layer for shielding electromagnetic waves generated by a digital apparatus. The top layer 3 is a light permeable synthetic resin layer having self-holding property as a casing. The inner layer 4 and the top layer 3 are laminated as a sheet-like laminate 8, and the sheet-like laminate is heated and molded into digital apparatus casing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a casing of a digital device, for example, a mobile phone, a personal computer, a DVD device, a DSC, a DVC, a game machine and the like, and a manufacturing method thereof.

  Synthetic resin moldings are usually used for the casings of these digital devices, and electromagnetic wave shielding is applied in order to reduce leakage of electromagnetic waves emitted by the devices. Patent Document 1 discloses a housing of an electronic device in which an electromagnetic wave shielding layer is formed on a resin molded body having a predetermined shape via an adhesive layer, and an insulating resin layer is further provided on the electromagnetic wave shielding layer. Yes. Patent Document 2 discloses a resin casing in which a decorative sheet having a decorative surface on the front surface and a conductive pattern layer on the back surface is integrally adhered to the surface of the resin molded body. .

  In short, the invention described in Patent Document 1 provides an electromagnetic wave shielding molded body having an electromagnetic wave shielding layer that can closely follow a surface of a three-dimensional shape that is somewhat free and does not corrode for a long period of time. Patent Document 2 describes that there is no adverse effect on workers and the global environment, a sufficient shielding effect for electromagnetic waves, and a resinous casing having a decorative property on the surface and a method for manufacturing the same. Yes.

  In Patent Document 1, an electromagnetic wave shielding layer is provided inside the molded body. In Patent Document 2, there is a difference in that the decorative sheet of the conductive pattern layer is integrally provided on the surface of the molded body. The inventions described in Patent Documents 1 and 2 disclose a technique in which an electromagnetic wave shielding layer is closely integrated with a resin molded body that forms a housing or housing of an electronic device, and both are disclosed as electromagnetic wave shielding films (conductive patterns). The integration of the decorative sheet having a layer) and the resin molding is described as being performed by injection molding.

  Certainly, when injection molding is used, the electromagnetic wave shielding film (decorative sheet having a conductive pattern layer) and the resin molded body can be reliably integrated, but according to the shape of the cavity of the injection mold. There is a problem that the electromagnetic wave shielding film (or decorative sheet) must be set in a molding die, and the die shape is limited to a simple shape.

  Moreover, according to the method using the decorative sheet as described in Patent Document 2 regarding the surface design of the housing (housing), although the design and the pattern can be expressed by selecting the material, Since it needs to be set according to the shape of the cavity, it is limited to one having flexibility, and a hard material cannot be used for the decorative sheet.

Further, Patent Document 1 does not particularly mention the surface decoration of the housing. Perhaps the resin selected for injection molding is arbitrarily colored to form a surface design.
JP-A-6-314895 JP 10-27983 A

  The problem to be solved is that when the electromagnetic wave shielding layer and the resin molded body are integrated by injection molding, not only the work for attaching the electromagnetic wave shielding layer to the molding die is required, but the work efficiency is poor. It is a problem. As for the design of the housing, when the decorative sheet is attached to the molding die and integrated with the injection resin, the material of the decorative sheet is restricted, so it is difficult to express the hard feeling of the surface, The problem is that the surface decoration is limited.

  The present invention provides a three-dimensional shape as a case by heat-molding a sheet-like laminate comprising at least a synthetic resin sheet and an electromagnetic wave shielding layer, and has a light-transmitting property having self-holding properties as a case. The most important feature is that the electromagnetic shielding layer is integrated with the synthetic resin layer.

  According to the housing for digital equipment of the present invention, since a sheet-like laminate obtained by laminating a synthetic resin sheet and an electromagnetic wave shielding layer is heat-molded, an arbitrary three-dimensional shape can be imparted, and at least the electromagnetic wave shielding layer and necessary By using a decorative layer laminated on the surface of the electromagnetic wave shielding layer as an inner layer and selecting a light-transmitting synthetic resin layer having a self-holding property as a housing as a surface layer, the surface of the inner layer is passed through the surface layer as a design surface. The design surface can be seen through, and by forming various design surfaces on the inner layer, the surface layer functions as a top coat of the inner layer design as well as the structure of the housing.

  The housing of the digital device of the present invention has a three-dimensional shape by thermoforming a sheet-like laminate in which a surface layer and an inner layer are laminated in advance for the purpose of integrating an electromagnetic wave shielding layer and a synthetic resin layer with good adhesion. The purpose of imparting a design to the housing was realized by allowing the inner decorative layer to permeate.

  FIG. 1A shows an example in which the casing of the present invention is applied to a casing of a mobile phone. For example, in a folding mobile phone, a keyboard-side casing 1 and a display-side casing 2 are connected so as to be openable and closable, but the present invention forms all these casings. is there. Of course, the present invention is not limited to application to the casing of a mobile phone. FIG.1 (b) is an enlarged view which shows the AA cross section of Fig.1 (a).

  The housing according to the present invention is a laminate of the inner layer 4 and the surface layer 3. The inner layer 4 is a layer whose surface forms a housing design, and has at least an electromagnetic wave shielding layer 5. The electromagnetic wave shielding layer 5 is a magnetic composition layer that blocks electromagnetic waves emitted by digital equipment. The surface layer 3 is a light-transmitting synthetic resin layer having a self-holding property as a housing, and is a layer that allows the surface of the inner layer 4 to be seen through.

  In FIG. 2, the example of the laminated structure of the inner layer 4 and the surface layer 3 is shown. FIG. 2A shows an example in which the inner layer 4 includes a decorative layer 6 and an electromagnetic wave shielding layer 5, and the surface of the decorative layer 6 is covered with the surface layer 3. FIG. 2B shows an example in which the inner layer 4 serves as a decorative layer and an electromagnetic wave shielding layer. In this example, the surface of the electromagnetic wave shielding layer 5 selected as the inner layer in order to block electromagnetic waves emitted from the digital device is seen through the surface layer as a design surface. FIG. 2C is an example in which the inner layer 4 serving both as a decorative layer and an electromagnetic wave shielding layer is used as in FIG. 2B, but in this example, a design effect is further imparted to the electromagnetic wave shielding layer 5. For example, a metal mesh 7 is added. Accordingly, the fine glossy surface of the metal mesh 7 is expressed as a design through the surface layer. In the present invention, since a synthetic resin layer having self-holding property is used for the surface layer, a reinforcing layer is not required for the inner layer, but a layer other than the decorative layer and the electromagnetic wave shielding layer may be further laminated.

(1) Inner layer (1-1) Electromagnetic wave shielding layer The inner layer 4 has at least an electromagnetic wave shielding layer 5, and the electromagnetic wave shielding layer 5 is a magnetic composition layer of a composition that blocks electromagnetic waves emitted by digital equipment. . As the magnetic composition, a magnetic powder in which ferrite particles are bound with a binder can be used. When selecting the ferrite particles, at least 50% by weight or more of ferrite particles having an average particle diameter of 2 to 40 μm are contained.

In this example, Fe ₂ O ₃ 45 to 50 mol%, NiO 10 to 20 mol%, ZnO 25 to 40 mol%, CuO 5 to 10 mol%, Mg—Zn as a Ni—Zn-based ferrite composition are used as ferrite particles. Fe ₂ O ₃ 45 to 50 mol%, MnO 1 to 10 mol%, ZnO 15 to 25 mol%, MgO 25 to 35 mol% as an Fe-based ferrite composition, and Fe ₂ O ₃ 50 as an Mn—Zn-based ferrite composition -55 mol%, MnO 30-40 mol%, ZnO 5-15 mol% were selected.

These compositions are adjusted in the above composition range, classified so as not to contain coarse particles as much as possible, and then the ferrite magnetic powder is uniformly dispersed in a synthetic resin. The particle size distribution of the ferrite particles is a volume average. Magnetic particles having a particle size of 2 to 40 μm, coarse particles of 100 μm or more of 5% or less, compression density of 3.0 to 3.8 g / cm ³ , magnetic permeability of 500 or more and maximum magnetization of 40 to 60 Am ² / kg as materials. It is desirable to have a characteristic. The compression density is determined by putting a certain amount of target powder in a compression density measurement mold (φ25 mm cylindrical mold) and dividing the weight of the target powder by applying a pressure of 1.0 ton / cm ² from the upper mold. (Unit: g / cm ³ ). The maximum magnetization (σm) was determined by applying a magnetic field of 1 kOe (= about 7.96 × 104 A / m) to 50 mg of powder with a VSM measuring device (vibrating sample magnetometer) (unit: Am ² / kg).

When the compression density is 3.0 g / cm ³ or less, the smaller the density is, the larger the powder particle size is, the hollow particles are included, and the damping characteristics tend to be inferior. When the compression density is 3.8 g / cm ³ or more, the particle size of the powder is large, so the thickness of the composite magnetic composition is controlled by the screen printing method. Not preferable. As described above, it is important that the particle size distribution is adjusted so that the volume average particle diameter is adjusted to a predetermined range and coarse particles are not included as much as possible.

As the magnetic composition, soft magnetic metal particles bonded with a binder can be used. For the soft magnetic metal particles, the metal particles are adjusted in the composition range of Fe: 60 to 78, Si: 18 to 30, Cr: 0 to 19 (atomic ratio%) so as to obtain desired magnetic properties as a powder. In addition, the volume average particle diameter is adjusted to a predetermined range, and coarse particles are classified so as not to be contained as much as possible, and are uniformly dispersed in a synthetic resin as a binder. The particle size distribution of the soft magnetic metal particles has a weight average particle size of 5 to 30 μm, coarse particles of 100 μm or more are 5% or less, bulk density is 0.15 to 0.35 g / cm ³ , and the material has a magnetic permeability of 2500 or more. It is desirable that the magnetic properties have a maximum magnetization of 60 Am ² / kg or more. Of course, magnetic powder and soft magnetic metal particles can be used in combination in the magnetic composition layer.

  If the average particle size, coarse particles, compression density, bulk density, and magnetic properties of the material are out of the above ranges as magnetic powder, the noise attenuation characteristics will be inferior, and the noise attenuation effect in the target frequency band that is the original purpose will be sufficient Can't get to. When the weight ratio and thickness of the composite magnetic composition are out of the above ranges, the noise attenuation characteristics that are the original purpose are affected. The electromagnetic wave shielding layer is formed to have a constant thickness within a range of 50 μm to 1000 μm on one surface of the outer layer using, for example, a screen printing method. The thickness is more preferably in the range of 50 μm to 500 μm.

(1-2) Cosmetic layer The decorative layer is a portion that forms the surface of the inner layer 4 that is transmitted through the surface layer 3 and seen from the outside. In FIG. 2A, the decorative layer 6 is provided as one layer of the inner layer 4. The decorative layer 6 is, for example, a color printing layer. A decorative layer having an arbitrary pattern and color can be formed using a screen printing technique. Furthermore, not only simple patterns and colors, but various designs such as hologram effects and deflection effects can be expressed in the patterns.

  In FIGS. 2B and 2C, the inner layer 4 is a single layer, and there is no distinction between a decorative layer and an electromagnetic wave shielding layer. In FIG. 2B, the color of the color tone of the synthetic resin used for the composite magnetic composition layer and the magnetic powder is expressed. In FIG. 2C, the composite magnetic composition layer as the inner layer is expressed. The metal mesh 7 is mixed in, and the mixed metal mesh 7 appears as a hologram pattern.

(2) Surface layer Surface layer 3 is a light-transmitting synthetic resin layer having a self-holding property as a casing, and has high light transmittance (transparency), heat resistance, flame resistance, impact resistance, chemical resistance. A composition having excellent properties is used. The thickness of the synthetic resin layer of the surface layer 3 is preferably 0.5 mm to 2.0 mm. As the surface layer 3, a rubber-containing acrylic resin, which is a thermoplastic resin having a high light transmittance (transparency) following glass, can be used, and a transparent ABS resin and polycarbonate engineering plastic can be used. When the casing is processed by heat molding, the thickness of the surface layer 4 is preferably set to 2.0 mm or less.
An example of a method for manufacturing a casing of a digital device according to the present invention will be described below.

(3) Manufacturing method of housing The housing of the digital device of the present invention is obtained by sequentially performing a laminated sheet forming process and a molding process.
(3-1) Laminated sheet forming process The laminated sheet forming process is performed by printing at least one inner layer including an electromagnetic wave shielding layer on one surface of a light-transmitting thermoplastic synthetic resin sheet that is a surface layer of a housing. 4 is a process for forming a sheet-like laminate comprising a laminate of 4 and the surface layer 3. That is, at least one layer including the electromagnetic wave shielding layer 5 is laminated as one inner layer 4 on one surface of the light-transmitting thermoplastic synthetic resin sheet.

  3A, the inner layer 4 is laminated by screen printing. When the inner layer 4 includes the decorative layer 6 and the electromagnetic wave shielding layer 5, the decorative layer 6 is first screen-printed on one surface of the surface layer 3, Next, the electromagnetic wave shielding layer 5 is screen-printed on the surface of the decorative layer 6 as shown in FIG. When the inner layer 4 serves as a decorative layer and an electromagnetic wave shielding layer, only one layer is screen-printed. By the printing process, a sheet-like laminate 8 having two or three layers as a laminate of the inner layer 4 and the surface layer 3 is obtained.

(3-2) Forming process The forming process is performed by softening the sheet-like laminate 8 while heating the sheet-like laminate 8 after the laminated sheet forming process, and heat-molding the softened sheet-like laminate 8 ( Vacuum forming process), and the sheet-like laminate 8 is processed into the shape of the casing of the digital device. In the molding process, when polycarbonate is selected as the light-transmitting thermoplastic synthetic resin sheet, the sheet-like laminate 8 is heated at a temperature of 150 to 180 ° C. for 1 to 3 minutes as shown in FIG. As shown in FIG. 3 (d), set in the vacuum forming die 9, deaerate the inside of the die, deform the sheet-like laminate following the shape of the cavity of the die, and give a three-dimensional shape as a housing. 1 is processed into the shape of the casings 1 and 2 shown in FIG.

  Of course, in this embodiment, an example of processing the casing of the mobile phone is shown, but the casing is not necessarily limited to a solid body, and may be processed into a flat plate such as a lid of a battery case, for example. For example, in a mobile phone, a battery cover or the like is a part of the housing of the mobile phone. The sheet-like laminate is processed into a casing by the above-described processing, and the surface of the inner layer 4 is seen through from the outside through the synthetic resin layer of the surface layer 3 as shown in FIG. Is expressed as the pattern and color of the housing.

  In the present invention, a sheet-like laminate which is a laminate of a surface layer 3 which is a light-transmitting synthetic resin layer having a self-holding property as a housing and an inner layer 4 including an electromagnetic wave shielding layer 5 formed of a magnetic composition layer Since the object 8 is heat-molded, an arbitrary three-dimensional shape is given, and the electromagnetic wave shielding layer 5 as the inner layer 4 and the synthetic resin layer as the surface layer 3 can be reliably integrated, and the shape of the housing is somewhat complicated. Even if there is unevenness, it can be molded into a free form as long as vacuum forming is possible. Further, by using a transparent synthetic resin layer for the surface layer 3, the surface of the inner layer 4 can be used as a design surface and the surface of the costume can be seen through the surface layer. The surface layer 3 is a structural body of the casing and the design of the inner layer. As a top coat, the design surface can be protected.

  Of course, by providing the decorative layer 6 positively on the inner layer, the design of the housing can be changed. In the present invention, the use of a magnetic composition layer of ferrite particles for the electromagnetic wave shielding layer plays an important role in electromagnetic wave shielding. That is, since the electrical circuit of the device housed in the housing is magnetically shielded by the ferrite layer having good frequency characteristics, the shielding effect at a high frequency is enhanced as compared with the conductive material.

  The present invention includes mobile phones, personal computers, DVD devices, DSCs, DVCs, information devices such as game machines, digital home appliances, immobilizers such as automobile keyless, shields for non-contact IC antennas, casings such as RFID, In addition to being adapted to the portable terminal systems PDC, cdmaone, and IMT-2000, it is also adapted to the standards of RFID ISO 14443 and ISO 15693.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention, in which FIG. (A)-(c) is a figure which shows the example of a sheet-like laminated body. (A)-(d) is a figure which shows the manufacturing process of a housing | casing in order of a process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Keyboard side housing | casing 2 Display side housing | casing 3 Surface layer 4 Inner layer 5 Electromagnetic wave shielding layer 6 Cosmetic layer 7 Metal mesh 8 Sheet-like laminate 9 Vacuum forming die

Claims (14)

A housing of a digital device having a laminated structure of an inner layer and a surface layer,
The inner layer has at least an electromagnetic wave shielding layer,
The electromagnetic wave shielding layer is a magnetic composition layer that blocks electromagnetic waves emitted by digital devices,
A casing of a digital device, wherein the surface layer is a light-transmitting synthetic resin layer having a self-holding property as the casing.   The casing of the digital device according to claim 1, wherein the surface layer allows the surface of the inner layer to be seen through. The inner layer forms the design of the housing,
The casing of the digital device according to claim 1, wherein the surface layer is a casing structure that also serves as a top coat of the casing. The surface layer is three-dimensionally formed as a casing of a digital device,
The casing of the digital device according to claim 1, 2, or 3, wherein the inner layer is formed on the inner surface side of the casing in the shape of a three-dimensional surface layer.   The casing of a digital device according to claim 1, 2, 3, or 4, wherein the inner layer includes a laminate of a decorative layer and an electromagnetic wave shielding layer, and the decorative layer is seen through the surface layer.   The casing of a digital device according to claim 1, 2, 3, 4, or 5, wherein the inner layer is formed as a single layer serving as a decorative layer and an electromagnetic wave shielding layer.   The casing of a digital device according to claim 1 or 2, wherein the casing is provided with a three-dimensional shape by heat-molding a sheet-like laminate in which a surface layer and an inner layer are laminated.   The casing of a digital device according to claim 5 or 6, wherein the decorative layer is screen-printed on the back surface of the surface layer forming the casing, and the electromagnetic wave shielding layer is screen-printed on the back surface of the decorative layer. .   The casing of a digital device according to claim 1, wherein the magnetic composition layer of the inner layer includes at least ferrite particles having an average particle diameter of 2 to 40 µm and a binder.   The casing of the digital device according to claim 9, wherein the magnetic composition layer of the inner layer is a layer having a thickness of 50 μm to 1000 μm.   The casing of a digital device according to claim 1 or 9, wherein the magnetic composition layer of the inner layer includes at least one kind of soft magnetic metal particles and magnetic powder particles.   6. The casing of a digital device according to claim 1, wherein the electromagnetic wave shielding layer magnetically shields the device in the casing.   The casing of a digital device according to claim 1, wherein the synthetic resin layer of the surface layer is a thermoplastic resin that can be heat-molded and is light transmissive, and has a thickness of 0.5 mm to 2.0 mm. body. A method for manufacturing a casing of a digital device having a laminated sheet forming process and a molding process,
In the laminated sheet forming process, at least one inner layer including an electromagnetic wave shielding layer is printed on one surface of a light-transmitting thermoplastic synthetic resin sheet to be a surface layer of a casing, and a sheet shape formed by laminating an inner layer and a surface layer A process of forming a laminate,
In the molding process, the sheet-like laminate obtained by the lamination sheet forming process is softened while being heated, and the softened sheet-like laminate is subjected to thermoforming to form the sheet-like laminate into the shape of the casing of the digital device. A method for manufacturing a casing of a digital device, characterized in that the processing is processing.

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