JP2007335820A - Gasket, laminate of circuit board using it, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasket easy to manufacture which can inhibit slack of a conductive sheet in use condition. <P>SOLUTION: The gasket 10 is configured by providing the conductive sheet 3 around a to-be-compressed member 11. The to-be-compressed member 11 has a structure wherein a cushioning material 2, a core material 1 and the cushioning material 2 are laminated. The core material 1 has larger elastic modulus compared with the cushioning material 2. Thereby, in the state that the gasket 10 is compressed, the amount of falloff of the height of the to-be-compressed member 11 due to compression is inhibited, so that slack of the conductive sheet 3 can be reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gasket, and a circuit board laminate and an electronic device using the gasket.

  Conventionally, electrical continuity (hereinafter simply referred to as “conduction”) such as ground (GND) is ensured for conductors with gaps, such as between substrates and between a substrate and a metal cabinet. Therefore, gaskets are widely used.

  FIG. 9 shows the structure of a conventional gasket 100. As shown in FIG. 9, the gasket 100 has a structure in which a conductive sheet 103 which is a conductive sheet is wound around a cushion material 102 made of urethane foam or the like.

  As a method of using the gasket, first, the gasket is sandwiched between conductors requiring conduction, for example, between substrates. Next, by bringing the substrates closer to each other, the gasket is compressed, and the conductive sheet is pressed against the substrates by the repulsive force of the core material, and conduction between the substrates is ensured.

  FIG. 10 shows a state in which the conventional gasket 100 is used. In the illustrated case, the gasket 100 is sandwiched between two substrates 105 and 105. Further, the two substrates 105 and 105 compress the gasket 100. For this reason, since the repulsive force F acts on the board | substrate 105 via the conductive sheet 103 from the compressed cushion material 102, the conductive sheet 103 is pressed against the board | substrate 105. FIG. Thereby, conduction between the two substrates 105 and 105 is ensured. Therefore, in order to stably secure the conduction by the gasket 100, it is necessary to appropriately compress the cushion material 102 so that a sufficient repulsive force from the cushion material 102 can be obtained.

  The conductive sheet 103 is loose on the side surface of the compressed gasket 100 for the following reason. Since the cushion material 102 is composed of urethane foam or the like, the cushion material 102 is greatly contracted in a direction in which pressure is applied, but the conductive sheet 103 is not contracted so much. For this reason, when the cushion material 102 is compressed, the conductive sheet 103 is loosened.

  Since the conductive sheet 103 is conductive, when the conductive sheet 103 is loosened, there is a risk of short-circuiting due to contact with surrounding components. Therefore, when using the gasket 100, it is necessary to ensure a sufficient space between the gasket 100 and surrounding components. This hinders downsizing of the apparatus.

  FIG. 11 shows a state before and after the gasket 100 is compressed by about 25%. FIG. 5A shows the gasket 100 before compression, and the length (height) in the direction perpendicular to the substrate 105 is 3.4 mm. FIG. 2B shows a state where the cushion material 102 of the gasket 100 shown in FIG. 1A is compressed by about 25% in the gap direction between the substrates 105 and 105. The symbol L in the drawing indicates slackness of the conductive sheet 103, and specifically indicates the maximum separation distance between the conductive sheet 103 and the cushion material 102. When a general urethane foam was used as the cushion material 102, the slack L of the conductive sheet 103 after compression was 0.91 mm.

  FIG. 12 shows a state before and after the gasket 100 is compressed by about 25% when the height of the gasket 100 is further increased. The figure (a) has shown the gasket 100 before compression, The height is 5.2 mm. FIG. 2B shows a state where the gasket 100 shown in FIG. 1A is compressed by about 25% in the direction perpendicular to the substrate 105. In this case, the slack L of the conductive sheet 103 was 1.58 mm.

  Comparing the slack L in FIG. 12B and FIG. 13B, the higher gasket 100 has a larger slack L than the lower gasket 100 even if the volume distortion is the same.

  When the interval between the conductive substrates is wide, the slack of the conductive sheet is particularly large. For this reason, in order to prevent a short circuit between the conductive sheet and the surrounding components, it is necessary to increase the interval that must be ensured between the gasket and the surrounding components. Therefore, there arises a problem that it is difficult to reduce the size of the electronic device in which the gasket is installed.

  Further, it is known that the repulsive force of the cushion material 102 depends on the volume distortion. FIG. 13 shows the relationship between the stress (repulsive force) of a certain cushion material and the volume strain. As a cushioning material, the above-mentioned product name PORON model number SR-S-40P is used, the sample shape is a cylinder with a diameter of 50 mm, and the compression rate is 1 mm / min. Was measured. As can be seen, it can be seen that the stress increases as the volumetric strain increases.

  Although the appropriate volume strain varies depending on the material of the cushion material, as shown in FIG. 13, when the volume strain is low, for example, 10% or less, the stress of the cushion material becomes a low value. On the other hand, when the volumetric strain is increased, the stress of the cushion material becomes high, but by compressing the cushion material for a long time and holding the state, the cushion material gradually loses its restoring force, and the repulsive force is reduced. A phenomenon of lowering occurs. The greater the volumetric strain, the more pronounced the reduction in restoring force. In general, the cushion material is used after being compressed so that the volumetric strain is about 25%.

  By the way, when installing a gasket, in order to prevent a gasket from moving by impacts, such as dropping, a gasket may be inserted in a cabinet. FIG. 14 shows a state before and after the conventional gasket 100 fitted in the cabinet 104 is compressed by about 25%.

  FIG. 14A shows the gasket 100 before compression. In FIG. 1A, the gasket 100 is fixed to a substrate 105 using a conductive double-sided tape 106. Further, a cabinet 104 that restricts the movement of the gasket 100 is installed on the substrate 105 on the side where the gasket 100 is fixed. The cabinet 104 has a structure that fits with the gasket 100, but has a structure in which an upper portion of the fitted gasket 100 is exposed. This is because the gasket 100 is compressed by the substrates 105 and 105.

  Next, FIG. 4B shows a state where the gasket 100 in FIG. In FIG. 5B, the gasket 100 is compressed by being sandwiched between the substrates 105, so that the conductive sheet 103 is loosened. Here, since the cabinet 104 regulates both side surfaces of the gasket 100, the slack L of the conductive sheet 103 is concentrated on the portion exposed from the cabinet 104. The maximum width of the slack L is 1.17 mm.

  As described above, even when the gasket 100 is formed in the cabinet 104, a predetermined interval must be ensured between the gasket 100 and surrounding components in order to avoid a short circuit. Therefore, as in the case of the gasket not formed in the cabinet, it is difficult to reduce the size of the electronic device in which the gasket is installed.

  With respect to the above problems, Patent Document 1 discloses a gasket that can suppress loosening of the conductive sheet during compression by forming the side surface of the cushion material in a constricted shape.

Another problem with the conventional gasket is that the workability of attaching the gasket is low. In order to solve this problem, Patent Document 2 discloses a foam having a hardness of 0.08 to 0.3 kg / cm ² and a density of 0.3 to 0.5 g / cm ³ at 25% compression. There is disclosed a gasket characterized by comprising a base made of the above and a plastic film fixed to one side of the base.
Japanese Patent Laid-Open No. 11-40975 (released on February 12, 1999) JP 2001-100216 A (released on April 13, 2001)

  However, although the gasket of patent document 1 can reduce the slack of a conductive sheet, it is necessary to process it into the shape where the center part of the side surface of the gasket was constricted toward the inner side. Therefore, a new problem arises that it is necessary to create a dedicated gasket according to the desired shape and size of the gasket.

  In addition, in the gasket 100 of FIG. 10, the conductive sheet 103 becomes loose as the compressed height of the cushion material 102 increases. Therefore, it is considered that a desired stress can be obtained by suppressing the volume distortion by using a material having a high elastic modulus as the cushion material 102. However, when a material having a high elastic modulus is used as the cushioning material, the conductive sheet may be cut by the corners of the cushioning material 102 pressing the bent portion of the conductive sheet 103 in the usage state of the gasket 100. . For this reason, a material having a low elastic modulus is generally used as the cushioning material 102 in contact with the conductive sheet 103.

  In addition, a general gasket manufacturing method is to cut a sheet-like cushion material into a strip shape, then wrap the conductive sheet around the cushion material, and finally cut it into a desired shape. Since a cushion material is used for the gasket, it is difficult to cut the gasket in a small size in the process of cutting the gasket.

  Since the gasket described in Patent Document 2 has a plastic film fixed to a base made of foam, it can be cut smaller than a gasket made only of a cushion material. That is, it can be said that a problem remains in the process of cutting the gasket.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a gasket that can suppress loosening of a conductive sheet in a use state and is easy to manufacture. Another object of the present invention is to provide a gasket that can suppress loosening of the conductive sheet in use and does not cause the conductive sheet to be cut.

  In order to solve the above problems, the gasket of the present invention is a gasket in which a conductive sheet is provided across both ends of the compressed member in the compressed direction. The compressed member has one or a plurality of low elastic moduli. The high compression layer and one or more low compression layers having a large elastic modulus are laminated in the compression direction, and the total thickness of the low compression layers is the thickness of the high compression layer. It is characterized by being approximately the same or larger than the sum of.

  According to the above invention, the member to be compressed has a low compression layer, and the total thickness of the low compression layer is the same as or larger than the total thickness of the high compression layer. Moreover, the volume distortion of the entire gasket can be effectively suppressed. Thereby, the slack of a conductive sheet can be reduced. Moreover, since the said effect is realizable by making a to-be-compressed member into a laminated structure, formation of a gasket is easy. Furthermore, various gaps can be easily accommodated by adjusting the thickness of the low compression layer in accordance with the gap to be conducted.

  Further, in order to solve the above problems, the gasket of the present invention is a gasket in which a conductive sheet is provided over both ends of the member to be compressed in the direction of compression. Is smaller than the elastic modulus of other parts.

  According to said invention, since the to-be-compressed member of a gasket has a large elasticity modulus other than both ends, the volume distortion of the whole gasket required in order to obtain desired stress can be suppressed effectively low. Thereby, the slack of a conductive sheet can be reduced. Moreover, since the volume distortion of the said both ends becomes large compared with the volume distortion of another part, it can prevent that a conductive sheet is cut | disconnected by the press of a to-be-compressed member.

  In the gasket of the present invention, the stress in the compressed state of about 25% of the high compression layer is 0.008 MPa or more and 0.032 MPa or less, and the stress in the compressed state of about 25% of the low compression layer is It is preferable that it is 0.08 MPa or more.

  In order to solve the above problems, an electronic board according to the present invention is characterized by comprising a plurality of circuit boards provided with the gasket compressed in a gap.

  According to the invention, since the gasket is used, there can be provided a circuit board laminate that can be reduced in size without the possibility of short circuit.

  Moreover, in order to solve the said subject, the electronic device of this invention is equipped with the said gasket, It is characterized by the above-mentioned.

  According to the above invention, it is possible to provide an electronic device that can be reduced in size without a short circuit between the conductive sheet and the electronic substrate.

  As described above, in the gasket of the present invention, the member to be compressed is formed by laminating one or more high compression layers having a small elastic modulus and one or more low compression layers having a large elastic modulus in the compression direction. The total thickness of the low compression layer is the same as or larger than the total thickness of the high compression layer.

  Therefore, the volume distortion of the entire gasket necessary for obtaining a desired stress can be effectively suppressed, and the effect of reducing the looseness of the conductive sheet is exhibited. Moreover, since the said effect is realizable by making a to-be-compressed member into laminated structure, there exists an effect that formation of a gasket is easy. Further, by adjusting the thickness of the low compression layer according to the gap to be conducted, there is an effect that various gaps can be easily handled.

  Further, as described above, in the gasket of the present invention, the member to be compressed has a smaller elastic modulus at the both end portions than that at the other portion.

  Therefore, the volume distortion of the entire gasket necessary for obtaining the desired stress can be effectively suppressed. Thereby, there exists an effect which reduces the slack of a conductive sheet. Moreover, since the volume distortion of the said both ends becomes large compared with the volume distortion of another part, there exists an effect that it can prevent that a conductive sheet is cut | disconnected by the press of a to-be-compressed member.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows the structure of the gasket 10 of the present embodiment. The gasket 10 is configured by providing the conductive sheet 3 around the compressed member 11. The member 11 to be compressed has a structure in which the cushion material 2, the core material 1, and the cushion material 2 are stacked in the direction to be compressed. The core material 1 has a larger elastic modulus than the cushion material 2.

  The core material 1 which is a low compression layer among the members to be compressed 11 has a function of supporting the gasket 10 when the gasket 10 is used. The number of layers of the core material 1 is not specifically limited, One layer may be sufficient and multiple layers may be sufficient. When the core material 1 is one layer, the gasket 10 can be manufactured simply and at low cost.

  As the material of the core material 1, foamed materials such as urethane foam, NBR (acrylonitrile-butadiene rubber) latex sponge, SBR (styrene-butadiene rubber) latex sponge, and polyolefin can be used. Although various materials can be used as described above, a material larger than the elastic modulus of the cushion material 2 is used as the material of the core material 1.

  Further, the elastic modulus of the core material 1 is not particularly limited as long as it is larger than the elastic modulus of the cushion material 2, but the stress in the compressed state is about 25% due to the looseness of the conductive sheet 3 described later. , 0.08 MPa or more is preferable.

  Further, the height of the core material 1 is not particularly limited, and may be set as appropriate depending on the gap for conducting by the gasket 10.

  The cushion material 2 which is a high compression layer among the members 11 to be compressed is disposed at both ends of the core material 1 in the direction to be compressed. That is, the two cushion materials 2 constitute both ends of the compressed member 11 in the compressed direction. Each cushion material 2 may be a single layer or a plurality of layers.

  As a material of the cushioning material 2, foaming materials such as urethane foam, NBR latex sponge, SBR latex sponge, and polyolefin can be used. In particular, urethane foam is preferred because it has good resilience after compression.

  The elastic modulus of the cushion material 2 is not particularly limited as long as it is smaller than the elastic modulus of the core material 1, and the cushion material 2 having an appropriate elastic modulus may be selected according to the situation of use. An elastic modulus comparable to that of the conventional cushion material 102 is preferable because a general-purpose cushion material can be used.

  What is necessary is just to set the height of the cushion material 2 suitably according to the condition to use, and it is not specifically limited. It is preferable that the heights of the two-layer cushion material 2 are the same, since it is not necessary to use the cushion material 2 having a different height in the manufacturing process of the gasket 10 and the manufacturing cost can be reduced.

  The conductive sheet 3 is for conducting both ends in the direction to be compressed. In the present invention, as the base of the conductive sheet 3, not only a polymer film but also a fabric knitted with fibers can be used. Therefore, as the conductive sheet 3, a thin film film obtained by vapor-depositing a metal such as nickel on a film such as a PET film, a cloth made of conductive fibers soaked with metal particles such as nickel, or the like can be used. Moreover, you may give a carbon coat to the said electrically conductive fiber and a thin film. Thereby, the abrasion resistance of the conductive sheet 3 is improved, and the metal can be prevented from peeling off.

  The conductive sheet 3 is desirably thin, but preferably has a thickness that does not break even when the member to be compressed 11 is compressed. In the present embodiment, the conductive sheet 3 is made of a thin film obtained by depositing a metal such as nickel on a film such as a PET film, and the thickness thereof is 0.05 mm.

  FIG. 2 shows a state before and after compressing the gasket 10. FIG. 2A shows the gasket 10 before compression, in which the core material 1 has a height of 3.00 mm, and the two-layer cushion material 2 has a height of 0.60 mm. As the core material 1, model number SR-HH-48 having a trade name PORON manufactured by Roger Sinoac Co., Ltd. is used. Moreover, as the cushioning material 2, the model number SR-S-32P of the brand name PORON made from Roger Sinoac Co., Ltd. is used. Under the trade name PORON, urethane foam is used as the member 11 to be compressed. Thus, as the core material 1 and the cushion material 2, the same material from which an elasticity modulus differs can be used.

  Further, FIG. 7B shows a state in which the cushion material 2 is compressed by about 25% in the direction perpendicular to the substrate 5 by compressing the gasket 10 shown in FIG. Yes. When the distance between the substrates 5 and 5 is 3.9 mm, the height of the core material 1 hardly changes because the elastic modulus is large. On the other hand, the height of the cushion material 2 is 0.45 mm, and the total height of the two layers of cushion materials 2 and 2 is 0.90 mm. That is, the height of the gasket 10 is reduced by about 0.30 mm. In this case, the slack L of the conductive sheet 3 is 0.8 mm.

  If the distance between the substrates 105 and 105 is set to 3.9 mm in the structure of the conventional gasket 100 having no core material as shown in FIG. 12, in order to compress the cushion material by about 25%, The height of the material needs to be 5.2 mm and is reduced by about 1.3 mm due to compression. According to the present invention, since the same distance between the substrates can be conducted with a small volume distortion, the slackness of the conductive sheet 3 can be reduced by 49.4% as compared with the conventional gasket 100.

  The manufacturing method of the gasket 10 is illustrated below. First, the one-layer core material 1 and the two-layer cushion material 2 are bonded to each other to create the member to be compressed 11. As a method of bonding, an adhesive is applied to the bonding surface while feeding the long core material 1 and cushion material 2 from the roller. Then, the core material 1 and the cushion material 2 are bonded together. The adhesive preferably has elasticity so that no peeling occurs between the core material 1 and the cushion material 2 when the gasket 10 is used. Further, if the two layers of the cushioning material 2 have the same height, a material having a different height is not necessary, so that the manufacturing cost can be reduced.

  Next, the compressed member 11 is cut in the stacking direction. The width to be cut is appropriately changed depending on the width to be conducted.

  Finally, the conductive sheet 3 is bonded so as to cover the cut member 11 to be compressed. A thermosetting adhesive is applied to one end of the sheet-like conductive sheet 3, and after the conductive sheet 3 is wound around the member to be compressed 11, the portion to which the adhesive is applied is heated. The both ends of the conductive sheet 3 are bonded to each other with the compressed member 11 covered. The gasket 10 is completed through the above steps. Further, the gasket 10 may be cut as necessary. Moreover, you may adhere | attach a conductive sheet so that only the both end surfaces and one side surface of the to-be-compressed member 11 may be covered.

  According to said manufacturing method, in the manufacturing process of the gasket 10, the core material 1 and the cushion material 2 are laminated | stacked, the to-be-compressed member 11 is manufactured, and also the conductive sheet 3 can be wound, and the gasket 10 can be manufactured. Therefore, the gasket 10 can be easily manufactured, and the manufacturing cost can be reduced.

  In the present embodiment, the gasket having a three-layer structure has been described. However, when there is no possibility that the conductive sheet 3 is cut, the core material 1 is one layer or more and the cushion material 2 is one layer or more in the gasket 10. Thus, the total thickness of the core material 1 can be set to be the same or larger than the total thickness of the cushion material 2.

  That is, since there is no possibility that the conductive sheet 3 is cut, a structure in which the core material 1 and the conductive sheet 3 are in contact with each other can be obtained. For example, the to-be-compressed member 11 may be comprised by the core material 1 of 1 layer, and the cushion material 2 of 1 layer, and each of the core material 1 and the cushion material 2 may be comprised by multiple layers. In addition, the sum total of the thickness of the core material 1 should just be the same as or larger than the sum total of the thickness of the cushion material 2, and is not specifically limited. That is, what is necessary is just to change suitably according to the condition to use.

  According to said structure, since the sum total of the thickness of the core material 1 is a structure comparable or larger than the sum total of the thickness of the cushion material 2, it is the structure of the whole gasket 10 required in order to obtain desired stress. Volumetric distortion can be effectively reduced. Thereby, the slack of the conductive sheet 3 can be reduced. Moreover, since the said effect is realizable by making the to-be-compressed member 11 into a laminated structure, formation of the gasket 10 is easy. Furthermore, by adjusting the thickness of the core material 1 in accordance with the gap to be conducted, various gaps can be easily handled.

  Further, even when the gasket 10 is cut into a small size, the total thickness of the core material 1 is approximately the same as or larger than the total thickness of the cushion material 2, so that the elastic modulus of the gasket 10 as a whole is large. Without being reduced, the gasket 10 can be easily cut into small pieces. Therefore, it is possible to provide the gasket 10 that can reduce the looseness of the conductive sheet and can be easily formed and cut.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. Note that configurations other than those described in this embodiment are the same as those in the above embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the above-described embodiment are given the same reference numerals, and the description thereof is omitted.

  FIG. 3 is a front view, a plan view, a bottom view, and a side view showing the appearance of the gasket 10. In the figure, a gasket 10 is provided with a conductive double-sided tape 6 for fixing to a substrate or the like on the lower conductive sheet 3. In the gasket 10 shown in FIG. 3, the height of the core material 1 of the member to be compressed 11 is higher than that of the gasket 10 shown in FIGS. 1 and 2.

  As shown in the figure, as an example of the gasket 10, the height of the gasket 10 can be 4.5 mm, the depth can be 6.80 mm, and the width can be 3.00 mm. Of the height of the gasket 10, the height of the conductive sheet 3 is 0.09 mm, the height of the cushion material 2 is 0.60 mm, the height of the core material 1 is 3.00 mm, and the height of the double-sided tape 6 is 0 .12 mm. These heights are merely examples, and can be appropriately changed according to the state in which the gasket 10 is used.

  FIG. 4 shows a state before and after compressing the gasket 10 fitted in the cabinet 4. FIG. 5A shows a state before compression. The gasket 10 is fixed to one substrate 5 using a conductive double-sided tape 6.

  Further, a cabinet 4 for restricting the movement of the gasket 10 is installed on the substrate 5. The cabinet 104 has a structure that fits with the gasket 100, but has a structure in which the upper portion of the fitted gasket 10 is exposed. This is because the gasket 10 is compressed by the substrates 5 and 5.

  Next, FIG. 4B shows a state in which the cushion material 2 is compressed by about 25% in the direction perpendicular to the substrate 5 by compressing the gasket 10 in FIG. Yes. In FIG. 6A, the distance between the substrates 5 and 5 is 3.9 mm, similar to the gasket 10 in FIG. Since the compressed gasket 10 is sandwiched between the substrates 5, the conductive sheet 3 is loosened.

  Here, since the cabinet 4 regulates both side surfaces of the gasket 10, the slack L of the conductive sheet 3 is concentrated on the portion exposed from the cabinet 4. The maximum width of the slack L is 0.54 mm, and the slack L can be reduced by 54.3% as compared with the slack L of the conventional gasket 100 shown in FIG. Moreover, even if the interval between the substrates 5 and 5 to be conductive is increased, the adjustment can be made by the thickness of the core material 1, so that various intervals can be easily handled.

  In addition, this invention is not limited to said embodiment, A various change is possible within the scope of the present invention.

[Embodiment 3]
The following will describe another embodiment of the present invention with reference to FIGS. Note that configurations other than those described in this embodiment are the same as those in the above embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the above-described embodiment are given the same reference numerals, and the description thereof is omitted.

  The electronic circuit laminate 20 of the present embodiment has the configuration of the gasket 10 shown in FIG. FIG. 5 shows an exploded circuit board laminate 20. As shown in the figure, the circuit board laminate 20 includes a main board 7a that is one circuit board, a board holder 8, a gasket 10, and a sub board 7b that is the other circuit board. The substrate holder 8 is provided with a gasket installation portion 9 for installing a gasket.

  6 to 8 show an assembly process of the circuit board laminate 20. When the circuit board laminate 20 is assembled, the substrate holder 8 is first mounted on the main substrate 7a as shown in FIG. Further, as shown in FIG. 7, a gasket 10 is fitted in the gasket installation portion 9. Finally, as shown in FIG. 8, the sub-substrate 7b is mounted on the substrate holder 8, and the circuit board laminate 20 is completed. In the circuit board laminate 20, since the conductive cloth is less loose in the compressed gasket 10, it is possible to install other members around the gasket 10. Therefore, it is possible to provide the circuit board laminate 20 that can be miniaturized.

  The gasket 10 is suitable for use in a cellular phone, but can also be applied to electronic devices such as notebook PCs, liquid crystal displays, car navigation systems, and hard disks.

  Moreover, if it is an electronic device provided with the said gasket 10, similarly to the laminated body 20 of a circuit board, there is no possibility of short-circuiting and the electronic device which can be reduced in size can be provided.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the looseness of the electrically conductive cloth of a gasket can be reduced and the gasket which can be processed easily can be provided. Further, according to the present invention, it is possible to provide a gasket that can suppress the slackness of the conductive sheet in use and does not cause the conductive sheet to be cut.

  Therefore, the gasket of the present invention, and the circuit board laminate and electronic device using the gasket, the cellular phone, the notebook PC, the liquid crystal display, and the like, which are required to be highly integrated and downsized especially in the electronic device field, It can be suitably used in a car navigation system, a hard disk, and the like.

It is typical sectional drawing which shows the gasket which concerns on one Embodiment of this invention. (A) is typical sectional drawing which shows the said gasket of an unused state, (b) is typical sectional drawing which shows the said gasket of a use state. It is typical sectional drawing which shows the external appearance of the gasket which concerns on another embodiment of this invention. (A) is a typical sectional view showing the above-mentioned gasket in an unused state provided with a cabinet, and (b) is a typical sectional view showing the above-mentioned gasket in use provided with a cabinet. It is an exploded assembly figure of the laminated body of the circuit board concerning another embodiment of this invention. It is a disassembled assembly drawing of the laminated body of the said circuit board. It is a disassembled assembly drawing of the laminated body of the said circuit board. It is a perspective view which shows the laminated body of the said circuit board. It is typical sectional drawing which shows the structure of the conventional gasket. It is typical sectional drawing which shows the structure of the conventional gasket in use condition. It is a graph which shows the relationship between the volume distortion regarding a cushioning material, and stress. (A) is typical sectional drawing which shows the conventional gasket in an unused state, (b) is typical sectional drawing which shows the conventional gasket in a use state. (A) is typical sectional drawing which shows the conventional gasket in an unused state, (b) is typical sectional drawing which shows the conventional gasket in a use state. (A) is typical sectional drawing which shows the conventional gasket in an unused state provided with the cabinet, (b) is typical sectional drawing which shows the conventional gasket in the use condition provided with the cabinet.

Explanation of symbols

1 Core material (low compression layer / compressed member)
2 Cushion material (high compression layer / compressed member)
3 conductive sheet 4 cabinet 5 board 6 double-sided tape 7a main board (circuit board)
7b Sub-board (circuit board)
8 Board holder 9 Gasket installation part 10 Gasket 20 Laminate of circuit boards

Claims (5)

In the gasket provided with the conductive sheet across the both ends of the compressed direction in the compressed member,
The member to be compressed has a structure in which one or more high compression layers having a small elastic modulus and one or more low compression layers having a large elastic modulus are laminated in the compression direction.
The gasket according to claim 1, wherein the total thickness of the low compression layer is equal to or greater than the total thickness of the high compression layer. In the gasket provided with the conductive sheet across the both ends of the compressed direction in the compressed member,
The gasket to be compressed is characterized in that the elastic modulus of the both end portions is smaller than the elastic modulus of other portions. The stress in the 25% compression state of the high compression layer is 0.008 MPa or more and 0.032 MPa or less,
The gasket according to any one of claims 1 and 2, wherein a stress in a 25% compression state of the low compression layer is 0.08 MPa or more.   A laminate of circuit boards comprising a plurality of circuit boards provided by compressing the gasket according to any one of claims 1 to 3 in a gap.   An electronic apparatus comprising the gasket according to any one of claims 1 to 3.

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