JP2009253177A - Gasket for electromagnetic shield, and pluggable optical data link - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasket for an electromagnetic shield, which blocks a gap between an electronic device and a host device, and for which large force is unnecessary when the electronic device is fixed to the host device, etc. even if the gasket is made into the shape so as to block the gap within a range of variations in dimension. <P>SOLUTION: The gasket 1 for the electromagnetic shield is annular one which is formed by an elastic material and has conductivity, both edges of a tube-like member are mutually connected and annularly formed. In the gasket 1 for the electromagnetic shield, the gasket 1 is tightly adhered and attached to the surroundings of a casing 13 of an optical data link 10 by prescribed tension. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic shielding gasket that performs electromagnetic shielding of an electronic device to which an electronic device such as a pluggable optical data link is attached, and a pluggable optical data link including the gasket.

A pluggable optical data link (hereinafter referred to as an optical data link) is used by being detachably attached to an information equipment device (host device) body such as a computer or a router that performs optical communication.
FIG. 4 is a diagram for explaining an example of the structure of a general optical data link. FIG. 4A shows a state where an optical data link conforming to X2 MSA is attached to a host device, and FIG. ) Shows an example of the optical data link mounting portion of the host device. 5A and 5B are diagrams for explaining an example of a conventional optical data link. FIGS. 5A and 5B show a state in which the optical data link is viewed from the rear and side, respectively. ) Shows a ZZ cross section of the optical data link of FIG.

  As shown in FIG. 4A, the optical data link 10 has an optical receptacle 11 into which an optical connector (not shown) is inserted in front thereof. In the optical data link 10, when an optical connector is inserted into the optical receptacle 11, the optical fiber in the optical connector and the optical module in the optical data link 10 are optically coupled to transmit / receive optical signals. It becomes like this.

  As shown in FIG. 4B, the host device on which the optical data link 10 is mounted has a face panel 21 on a circuit board (hereinafter referred to as host board) 20, and the optical data link 10 is provided on the face panel 21. An opening 21a is formed in which is inserted. The host substrate 20 has a metal rail 22 that guides insertion / extraction of the optical data link 10, and the rail 22 is continuous with the opening 21 a of the face panel 21. An electrical connector 23 that electrically connects the optical data link 10 and the host board 20 is disposed behind the rail 22.

  When the optical data link 10 is inserted into the opening 21a of the face panel 21 from behind, the optical data link 10 is guided by the rail 22, and the latch piece 12 provided on the side surface and the engagement hole 22a on the side surface of the rail 22 are engaged. As a result, they are fixed to the host substrate 20 (see FIG. 4A). The optical data link 10 can be inserted into and removed from the rail 22 by engaging or releasing the engagement between the latch piece 12 and the engagement hole 22a.

If there is an unoccluded gap between the housing 13 of the optical data link 10 and the opening 21a of the face panel 21 in a state where the optical data link 10 is fixed to the host substrate 20, the gap goes to the outside of the apparatus. Electromagnetic interference (EMI) occurs.
Conventionally, in order to reduce the unnecessary radiation of electromagnetic noise to the outside, there is known a technique in which a conductive finger is provided around a casing of an optical data link and brought into contact with a metal face panel.

  A technique is also known in which a bezel (flange) 14 is provided in the optical data link 10 and an electromagnetic shielding gasket is used. The electromagnetic shielding gasket for reducing electromagnetic radiation can close the gap as described above by being compressed and sandwiched between the bezel of the optical data link and the face panel of the host device. As an electromagnetic shielding gasket, as shown in FIG. 4B, there is a metal sheet-like gasket 24 that is also found in other electronic devices (for example, mobile phones and personal computers). It is used in the state provided in.

As an electromagnetic shielding gasket, as shown in FIG. 5, there is an O-ring-shaped gasket 25 made of an elastic material coated with a conductive material, which is provided around the casing 13 of the optical data link 10. It is used in the provided state (see, for example, Patent Document 1).
JP 2005-316484 A

  However, in the technology using conductive fingers, the gap between the optical data link housing and the opening of the face panel cannot be completely closed by the fingers, so that the shield frequency can be reduced for further increase in signal frequency. Strengthening is required.

Further, the optical data link 10 is not positioned by hitting the face panel 21 but is positioned by the latch piece 12 and the rail 22 so that the distance between the bezel 14 and the face panel 21 varies. Is large (see FIG. 4). The metal sheet-like electromagnetic shielding gasket 24 cannot cope with this variation.
Further, when the optical data link 10 is fixed by the latch piece 12, it is necessary to push and latch the optical data link 10 slightly behind the position where it is normally fixed. It is difficult for the sheet-like electromagnetic shielding gasket 24 to maintain close contact even when the optical data link 10 is fixed at a position slightly returned after being pushed in and latched.

  By forming the O-ring gasket 25 made of an elastic material as shown in FIG. 5 thick, there is a gap between the optical data link housing and the face panel opening, even if there are variations. Can be blocked. However, in this case, when the distance between the bezel and the face panel is small, it is necessary to apply a large force when the user pushes the optical data link to the position where the optical data link is latched.

  The present invention is made in view of the above circumstances, and closes a gap such as between an electronic device and a host device, and can be inserted without requiring a large pushing force, and the gasket for the electromagnetic shield An object of the present invention is to provide a pluggable optical data link.

  In order to solve the above problems, the electromagnetic shielding gasket of the present invention is formed of an elastic material and has an annular shape having conductivity, and is formed in an annular shape by connecting both ends of a tubular member. It is characterized by that.

Moreover, it is preferable that the tube-shaped member is formed with a through hole penetrating from the hollow to the outside.
The present invention includes a conductive casing, and can be a pluggable optical data link attached to the casing in a state where the electromagnetic shielding gasket is extended. In that case, it is preferable that a step is provided in the casing so as to surround the outer periphery, and the electromagnetic shielding gasket is attached to a lower portion of the step.

  According to the present invention, the electromagnetic shielding gasket is made of a tube-shaped member having a hollow cross section formed of an elastic material, and thus can be easily deformed, so that a gap such as between an electronic device and an apparatus is always blocked. Even in such a shape, the force when fixing the electronic device to the apparatus can be suppressed.

  1 to 3 are views for explaining an example of an electromagnetic shielding gasket (hereinafter referred to as a gasket) according to the present invention. 1A shows the appearance of the gasket, FIG. 1B shows an XX cross section of the gasket of FIG. 1A, and FIG. 2A shows the optical data link of the gasket of FIG. FIG. 2B shows a Y-Y cross section of the optical data link of FIG. 2A. FIG. 3A is a cross-sectional view of the vicinity of the gasket of the optical data link mounted on the host device, and FIGS. 3B and 3C are enlarged views of the dotted line portion of FIG. Show.

The gasket of the present invention is used by being disposed between an electronic device such as an optical data link and a host device in order to reduce electromagnetic radiation. As shown in FIG. 1A, the gasket has an annular shape having conductivity and elasticity, and is made of a tubular member having a hollow 1a as shown in FIG. The gasket 1 illustrated in the figure is formed by, for example, bonding both ends of a tube-shaped member (bar-shaped member having a hollow cross section) formed of an elastic material (silicon or the like) to each other, and thereafter or before bonding the above-described member to the conductive material. It is formed by coating with. In addition, this gasket may use the filler (metal filler etc.) which has electroconductivity for the elastic material of a tubular member, and may give electroconductivity to a tubular member beforehand.
Further, one or a plurality of through-holes 1b penetrating from the hollow 1a to the outside of the tubular member are formed on the outer peripheral side of the gasket 1.

  The gasket 1 is used by being compressed (ie, deformed) between an electronic device and a host device. Even if the gasket 1 is formed thick (even if the outer diameter R1 of the cross section is increased), since the hollow 1a is provided, the gasket 1 is easily deformed. Even when a large amount of deformation is required, it can be easily deformed by providing the through hole 1b so that the air in the hollow 1a can escape. Further, by forming the inner diameter R2 in the cross section of the gasket 1 larger, it becomes easier to be crushed (easily deformed).

  As shown in FIG. 2A, the gasket 1 is used by being attached around the casing 13 of the optical data link 10. Unlike the conventional gasket 25 of FIG. 5, the gasket 1 of the present invention is attached in close contact with the periphery of the housing 13 of the optical data link 10 with a predetermined tension as shown in FIG. 2B. The length before installation of the gasket 1 (the length of the dotted line in FIG. 1A) L1 is shorter than the outer periphery of the gasket mounting portion of the housing 13 so that this tight mounting is possible. The gasket 1 is attached to the housing 13 in an extended state. That is, the gasket 1 has a length L2 after installation (the length of the dotted line in FIG. 2B) L2 longer than the length L1 before installation.

  The preferable dimensions of the gasket 1 are, for example, a length L1 of 91 mm before attachment, and an outer diameter R1 and an inner diameter R2 in the cross section (of the tube member) of 2.6 mm and 1.6 mm, respectively. Further, the gasket 1 has a length L2 of, for example, 100 mm after being attached. At that time, the outer diameter in the cross section of the gasket 1 becomes small but becomes a predetermined value or more.

More specifically, as shown in FIG. 3A, the gasket 1 is disposed between the bezel 14 of the optical data link 10 and the face panel 21 of the host device, so that the housing of the optical data link 10 is disposed. Used attached to the body 13.
The variation in the gap (distance) D between the bezel 14 of the optical data link 10 and the face panel 21 of the host device is defined by an industry standard or the like so as to be within a predetermined range. There is also a specification that fits within 0.096 inch (0.84 to 2.43 mm).
The gasket 1 closes a gap within the specified range and suppresses EMI.

  As shown in FIG. 3B, even when the gap D between the bezel 14 and the face panel 21 is the largest within the prescribed range (D = 2.43 mm), the gasket 1 is connected to the optical data link. It is possible to make the outer diameter of the cross-section after the attachment of the metal plate larger than a predetermined value (2.43 mm described above) and sufficiently contact the bezel 14 and the face panel 21. Therefore, even in this case, the gasket 1 can suppress EMI.

On the other hand, as shown in FIG. 3C, even when the gap D is the smallest within the prescribed range of the above example (D = 0.84 mm), the gasket 1 is made of the bezel 14, the lower surface of the housing 13, and the face. Fully contact the panel 21. Therefore, EMI can be suppressed even in this case.
Further, since the gasket 1 is provided with the through hole 1b, when the gap D is small, the gasket 1 is deformed so that the air in the hollow 1a is pushed out as shown in FIG. In this way, the gasket 1 provided with the hollow portion 1a can be easily deformed by providing a through hole 1b to suppress repulsion due to the air inside, and if the inner diameter in the cross section is further increased. It is more easily deformed.

  As described above, since the deformation is easy, the insertion force required for inserting / attaching the optical data link compliant with the X2 MSA with the gasket 1 attached to the host device (domination of gasket crushing) can be suppressed to 20 N or less. it can.

  Further, the gasket 1 is in close contact with the housing 13 of the optical data link 10 and has a thickness that can suppress EMI even when the gap D is 2.43 mm. When it is sandwiched between the front panel 21 and the bezel 14, it does not protrude from the bezel 14 (height is 3.4 mm in X2 MSA). Therefore, unlike the optical data link using the conventional gasket 25 (the one that bends and protrudes from the bezel when attached to the optical data link) of FIGS. The data link has the following effects.

  That is, in the optical data link using this gasket 1, the contact property of the gasket 1 to the housing 13 is good, and the gasket protrudes from the bezel when used in a host device to which a plurality of optical data links can be attached. Thus, the adjacent optical data link and the gasket 1 do not come into contact with each other.

  Preferably, a step is provided so as to surround the periphery of the optical data link housing to which the gasket 1 is attached, and a portion having a low step is used as a gasket attachment portion. By doing so, it is possible to reduce the possibility that the gasket protrudes from the flange when the optical data link from which the thick gasket is removed is attached to the host device.

It is a figure explaining an example of the gasket for electromagnetic shielding of this invention. It is a figure explaining an example of the pluggable optical data link to which the gasket for electromagnetic shielding of FIG. 1 was attached. It is a figure which shows the mode of a gasket when a pluggable optical data link is attached to a host apparatus. It is a figure explaining the conventional optical data link. It is a figure explaining the conventional optical data link.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gasket, 1a ... Hollow, 1b ... Through-hole, 10 ... Optical data link, 11 ... Optical receptacle, 12 ... Latch end, 13 ... Housing, 14 ... Bezel, 20 ... Host substrate, 21 ... Face panel, 21a ... Opening, 22 ... rail, 22a ... engagement hole, 23 ... electric connector, 24 ... electromagnetic shielding gasket, 25 ... gasket.

Claims (4)

An annular electromagnetic shielding gasket formed of an elastic material and having conductivity,
A gasket for electromagnetic shielding, wherein both ends of a tube-shaped member are connected to each other to form an annular shape.   2. The electromagnetic shielding gasket according to claim 1, wherein a through-hole penetrating from the hollow to the outside is formed in the tubular member.   A pluggable optical data link having a conductive casing, wherein the electromagnetic shielding gasket according to claim 1 is attached to the casing in a stretched state. Link.   4. The pluggable optical data link according to claim 3, wherein the casing is provided with a step so as to surround an outer periphery, and the electromagnetic shielding gasket is attached to a lower portion of the step.

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