CN114498205A

CN114498205A - Back panel connector

Info

Publication number: CN114498205A
Application number: CN202210229472.9A
Authority: CN
Inventors: 屈峰成
Original assignee: Shenzhen West Point Precision Technology Co ltd
Current assignee: Shenzhen West Point Precision Technology Co ltd
Priority date: 2022-03-10
Filing date: 2022-03-10
Publication date: 2022-05-13

Abstract

The application relates to a backplane connector, including first casing with inlay and locate second casing, a plurality of difference signal unit group and the shell of inhaling on the first casing. The plurality of differential signal unit groups are arranged on the first shell at intervals along a first direction, each differential signal unit group comprises a plurality of differential signal units which are arranged along a second direction intersecting with the first direction, each differential signal unit comprises two differential signal pins and a first shielding sheet, and the first shielding sheet at least partially surrounds the two differential signal pins. The wave-absorbing shell is embedded on the second shell and is fixedly connected with the first shell through the second shell; the wave-absorbing shell is at least partially blocked between two groups of differential signal unit groups adjacent along the first direction, so that all the differential signal unit groups are connected in common, resonance is inhibited, and the signal transmission rate can be effectively improved.

Description

Back panel connector

Technical Field

The invention relates to the technical field of connectors, in particular to a backplane connector.

Background

Backplane connectors are used to transmit high-speed signals and need to minimize crosstalk between differential signals. Typically, backplane connectors include a plurality of differential pairs made up of two differential signal pins and a plurality of shields that surround their corresponding differential pairs to provide electromagnetic shielding for the corresponding differential pairs.

In the related art, in order to increase the signal transmission rate, a metal dome shielding plate is often used to separate the differential pair and interconnect the differential pair to the ground to achieve resonance suppression, so as to increase the signal transmission rate, and a structural improvement is usually performed inside the plug to achieve ground interconnection, but this way has a limited effect on increasing the transmission rate.

Disclosure of Invention

In view of the above problems, the present application provides a backplane connector, which can solve the problem that the backplane connector in the related art has limited capability of increasing the rate of data transmission by performing a structural design inside a plug to interconnect with a ground.

The application provides a backplane connector, backplane connector includes first casing and inlays to be located second casing, a plurality of differential signal unit group and the shell of inhaling on the first casing. A plurality of differential signal unit groups are arranged on the first shell at intervals along a first direction, each differential signal unit group comprises a plurality of differential signal units arranged along a second direction intersecting with the first direction, each differential signal unit comprises two differential signal pins and a first shielding sheet, and the first shielding sheet at least partially surrounds the two differential signal pins; the wave-absorbing shell is embedded on the second shell and is fixedly connected with the first shell through the second shell; the wave-absorbing shell is at least partially blocked between two groups of differential signal unit groups adjacent along the first direction, so that all the differential signal unit groups are commonly interconnected.

Above-mentioned backplane connector will inhale and inlay on the ripples casing locates first casing to through second casing and first casing fixed connection. And the wave-absorbing shell is at least partially blocked between two groups of differential signal unit groups adjacent along the first direction, so that the plurality of differential signal unit groups are commonly interconnected. The first shell is used as a plug, the second shell and the wave-absorbing shell are used as a socket (namely, the first shell is used as a part of the plug, and the second shell and the wave-absorbing shell are used as a part of the socket), and the positions of the multiple pairs of differential signal pins and the multiple first shielding sheets which are mutually connected in common are arranged at the connecting positions of the plug and the socket, so that enough improvement space can be provided for effectively improving the signal transmission rate.

In some embodiments, the absorbent shell comprises a plurality of separator sheets; the plurality of separating sheets are arranged at intervals along the first direction, and a group of differential signal unit groups is arranged between every two adjacent separating sheets.

In some embodiments, the height of each separating sheet in the third direction is greater than or equal to the height of any first shielding sheet protruding out of the first shell in the third direction; wherein the third direction is perpendicular to the first direction and perpendicular to the second direction.

In some embodiments, the thickness of each of the separating sheets at any position in the first direction is smaller than the gap between two adjacent first shielding sheets in the first direction.

In some embodiments, the separation sheet is provided with a plurality of convex columns which are spaced from each other along the second direction and are arranged side by side; the extending direction of each convex column is parallel to the third direction.

In some embodiments, a height of any one of the protruding columns in the third direction is greater than or equal to a relative height of any one of the first shielding plates and the first housing in the third direction.

In some embodiments, the wave-absorbing shell further comprises a shell body; every the both ends of parting slip along lengthwise direction are equallyd divide respectively with casing body fixed connection, casing body with second casing fixed connection.

In some embodiments, the wave-absorbing shell is an integrally formed wave-absorbing material shell.

In some embodiments, a plurality of second shielding sheets are further disposed on the first shell; the plurality of second shielding pieces are arranged along the first direction at intervals, and any one of the second shielding pieces and the plurality of first shielding pieces in one group of the differential signal unit groups are arranged in a row at intervals in the second direction; each first shielding sheet is provided with an opening, the openings of the first shielding sheets in the same row in the second direction face to the second shielding sheets in the same row as the first shielding sheets in the same row.

In some embodiments, in the second direction, any of the first shielding sheets located in the same row is located on the same side of the second shielding sheets in the row.

The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.

Drawings

Various additional advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Moreover, like reference numerals are used to refer to like elements throughout. In the drawings:

fig. 1 is a block diagram of a first housing of a backplane connector as assembled into a header in an embodiment of the present application;

fig. 2 is a structural diagram of a wave-absorbing shell of a backplane connector when the wave-absorbing shell is assembled into a socket in an embodiment of the present application;

fig. 3 is a structural diagram of a wave-absorbing shell of a backplane connector in an embodiment of the present application;

fig. 4 is a schematic view of an assembly structure of a first shell and a wave-absorbing shell of a backplane connector in an embodiment of the present application;

fig. 5 is a schematic structural diagram of the backplane connector assembled in the backplane connector according to an embodiment of the present application.

The reference numbers in the detailed description are as follows:

the differential signal circuit comprises a first shell 1, a differential signal unit 11, a differential signal pin 111, a first shielding sheet 112 and a second shielding sheet 12;

the wave-absorbing shell 2, the separating sheet 21, the convex column 211 and the shell body 22;

a second housing 3;

and a wave absorbing plate 4.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are merely used to more clearly illustrate the technical solutions of the present application, and therefore are only examples, and the protection scope of the present application is not limited thereby.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof in the description and claims of this application and the description of the figures above, are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms "first", "second", and the like are used only for distinguishing different objects, and are not to be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary-secondary relationship of the technical features indicated. In the description of the embodiments of the present application, "a plurality" means two or more unless specifically defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is only one kind of association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), and similarly, "plural sets" refers to two or more (including two), and "plural pieces" refers to two or more (including two).

In the description of the embodiments of the present application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the directions or positional relationships indicated in the drawings, and are only for convenience of description of the embodiments of the present application and for simplicity of description, but do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and thus, should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are used in a broad sense, and for example, may be fixedly connected, detachably connected, or integrated; mechanical connection or electrical connection is also possible; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the embodiments of the present application can be understood by those of ordinary skill in the art according to specific situations.

As described in the background art, with the continuous development of the 5G information technology, a large number of high-speed backplane connectors are required to be used in data centers, communication base stations, servers and other devices, and the requirement for the transmission rate of the high-speed backplane connectors is higher and higher, which requires that the high-speed backplane connectors have better signal integrity in the process of transmitting signals, so that the transmission loss of the high-speed backplane connectors and the crosstalk amplitude and resonance between high-speed differential signals need to be reduced.

Typically, the backplane connector includes a plurality of differential pairs made up of two differential signal pins and a plurality of shields surrounding their corresponding set of differential signal pins to provide electromagnetic shielding for the corresponding differential pairs. In the related art, in order to increase the signal transmission rate, a metal dome shielding plate is often used to separate the differential pair and interconnect the differential pair to the ground to achieve resonance suppression, so as to increase the signal transmission rate.

The present inventors have noted that the open space between the plug and the receptacle of the backplane connector has a larger room for improvement, and if the open space between the plug and the receptacle can be utilized and the common ground interconnection structure of the backplane connector is disposed at the open space between the plug and the receptacle, the present inventors can provide more possibilities for increasing the data transmission rate of the high-speed backplane connector.

In view of the above, to solve the problem in the related art that the space for increasing the data transmission rate of the backplane connector is limited due to the space limitation of the plug portion of the backplane connector. The inventor designs a backplane connector through intensive research, and a common ground interconnection structure is arranged between a plug and a socket of the backplane connector, so that the data transmission rate of the high-speed backplane connector can be greatly improved.

The backplane connector disclosed in the embodiments of the present application may be, but is not limited to, a backplane connector provided in the present application, and the backplane connector may be used for transmission components of high-speed data transmission that need to interconnect signal units in common.

Fig. 1 shows a structure diagram of a first housing 1 of a backplane connector in an embodiment of the present application when assembled into a plug, and fig. 2 shows a structure diagram of a wave-absorbing housing 2 of a backplane connector in an embodiment of the present application when assembled into a socket.

Referring to fig. 1 and 2, the present application provides a backplane connector, which includes a first housing 1, a second housing 3 embedded on the first housing, a plurality of differential signal unit sets, and a wave-absorbing housing 2. A plurality of differential signal unit groups are arranged on the first housing 1 at intervals along a first direction, each differential signal unit group includes a plurality of differential signal units 11 arranged along a second direction intersecting the first direction, each differential signal unit 11 includes two differential signal pins 111 and a first shielding plate 112, and the first shielding plate 112 at least partially surrounds the two differential signal pins 111. The wave-absorbing shell 2 is embedded on the second shell 3 and is fixedly connected with the first shell 1 through the second shell 3; the wave-absorbing shell 2 is at least partially obstructed between two groups of differential signal elements adjacent in the first direction, so that all the groups of differential signal elements are commonly interconnected to suppress resonance.

It can be understood that, in the backplane connector, the wave-absorbing shell 2 is embedded on the first shell 1 and is fixedly connected with the first shell 1 through the second shell 3. And the wave-absorbing shell 2 is at least partially blocked between two groups of differential signal unit groups adjacent along the first direction, so that the plurality of differential signal unit groups are commonly interconnected.

More specifically, in each differential signal unit 11, the first shield plate 112 at least partially surrounds the two differential signal pins 111, and a reflow is formed on the inner surfaces of the two differential signal pins 111 and the first shield plate 112. Further, on the one hand, the presence of the first shield plate 112 can isolate the plurality of differential signal pins 111 from each other, reducing mutual crosstalk between each pair of differential signal pins 111, thereby suppressing resonance. On the other hand, the first shielding sheet 112 can reduce the influence on the signal transmission of each pair of differential signal pins 111 caused by the wave-absorbing shell 2 at least partially blocking between two adjacent groups of differential signal units along the first direction. The second shell 3 is embedded in the first shell, and the wave-absorbing shell 2 is embedded in the second shell (i.e., the first shell 1 is sleeved on the outer surface of the second shell 3, and the second shell 3 is sleeved on the outer surface of the wave-absorbing shell 2). Wherein the wave-absorbing housing 2 is embedded in the second housing 3 to form a socket part of the backplane connector, the first housing 1 forms a plug part of the backplane connector, and the plug part and the socket part of the backplane connector are connected with each other when the first housing 1 and the second housing are connected with each other.

It can be understood that the first housing 1 is used as the socket portion of the backplane connector, and the second housing 3 and the wave-absorbing housing 2 are fixedly connected to form the plug portion of the backplane connector, so that all the differential signal pins 111 and the first shielding plates 112 are grounded to the common ground when the plug and the socket are plugged together. The common ground of the traditional metal shielding sheet is required to be in a contact type, when the metal shielding sheet is repeatedly inserted and pulled, the metal spring sheet is easy to lose effectiveness due to multiple deformation, so that the effect of interconnection common ground is lost, and the use of the backplane connector is influenced. This application adopts and inhale the structure that ripples casing 2 shares ground as ground connection, inlay and establish on first casing 1, when carrying out the dismouting, because inhale ripples casing 2 and metallic shield piece realize sharing ground through contactless mode, inhale ripples casing 2 and metallic shield piece accessible separation, inhale ripples casing 2 and can not take place inefficacy, therefore it is more reliable to compare in the mode that traditional shell fragment formula contact's ground connection shares ground, avoid plug and socket to produce great insertion force and pull-out force and cause mechanical reliability's problem at the plug in-process, data transmission's integrality and validity still can be guaranteed, realize the transmission of 56Gbps and above speed.

In some embodiments, the second shell 3 is a shell made of an insulating material, the wave-absorbing shell 2 is a shell made of a wave-absorbing material, and the first shielding sheet 112 is a metal shielding sheet. When the wave-absorbing shell 2 is fixedly installed in cooperation with the first shell 1 and the second shell 3, the wave-absorbing shell 2 may scratch and rub against the first shielding sheet 112 made of metal on the first shell 1, so that some fragments of the wave-absorbing shell 2 and metal fragments may be generated, short circuit may occur in differential signal pins in the shielding sheets 112 in the heavy case, the impedance value of the backplane connector may be reduced in the light case, and such a problem may be prevented by the second shell 3 made of an insulating material.

In some embodiments, a plurality of second shielding sheets 12 are further disposed on the first housing 1. The plurality of second shield plates 12 are arranged at intervals along the first direction, and any one of the second shield plates 12 and the plurality of first shield plates 112 in one of the differential signal unit groups are arranged at intervals in a row along the second direction. Each first shielding sheet 112 is provided with an opening, and the openings of the first shielding sheets 112 in the same row in the second direction face the second shielding sheets 12 in the same row as the row of the first shielding sheets 112.

It is understood that the two differential signal pins 111 in each differential signal unit 11 are surrounded by four sides by one first shielding plate 112 and one second shielding plate 12, or the two differential signal pins 111 in each differential signal unit 11 are surrounded by one first shielding plate 112 and another first shielding plate 112 facing the opening of the first shielding plate 112. Thus, in fact, the two differential signal pins 111 in each differential signal unit 11 are all surrounded, and the signal transmission thereof is not affected by the signal transmission of the two differential signal pins 111 in the other differential signal units 11.

In some embodiments, the first shield sheet 112 and the second shield sheet 12 are both made of a metal material.

In some embodiments, the first shielding plate 112 has a U-shaped structure with three closed sides and one open side, and the second shielding plate 12 has a sheet-like structure, which is regular in structure and convenient for manufacturing and later maintenance and replacement.

In some embodiments, in the second direction, any first shield plate 112 located in the same row is located on the same side of the second shield plate 12 in the row.

That is to say, any first shielding plate 112 in the differential signal unit group of each group is all set up towards a direction (set up towards the same direction), therefore the first shielding plate 112 in each group of differential signal unit group and the composition structure of two differential signal needles 111 are all unanimous, and its arranging also follows the same rule of arranging, can make things convenient for the maintenance or the change in manufacturing and later stage.

In some embodiments, the first shell 1 and the second shell 3 are connected or interfitted with each other through a connecting piece, and the second shell 3 and the wave-absorbing shell 2 are connected or interfitted with each other through a connecting piece.

In some embodiments, the first direction is perpendicular to the second direction. Each differential signal unit 11 can thus be arranged regularly on the first housing 1, with a regular shape, and with greater versatility.

Fig. 3 shows a structural diagram of the wave-absorbing shell 2 of the backplane connector in an embodiment of the present application; fig. 4 shows an assembly structure schematic diagram of the first shell 1 and the wave-absorbing shell 2 of the backplane connector in an embodiment of the present application.

Referring to fig. 3 and 4, in some embodiments, the wave-absorbing shell 2 includes a plurality of separation sheets 21, the separation sheets 21 are arranged at intervals along the first direction, and a group of differential signal unit groups is disposed between every two adjacent separation sheets 21.

That is to say, a plurality of groups of differential signal unit groups are separated by the respective separating sheets 21, the separating sheets 21 separate magnetic fields formed in each differential signal unit group, and can filter interference between each differential signal unit group, and each group of separated differential signal unit groups do not interfere with each other due to electromagnetic shielding of the separating sheets 21, so as to play a role of electromagnetic protection, thereby realizing common connection of all the differential signal unit groups, ensuring that the differential signal pins 111 in all the differential signal units 11 can transmit signals independently without affecting each other, and further realizing high-speed data transmission.

In some embodiments, the height of each separating sheet 21 in the third direction is greater than or equal to the height of any first shielding sheet 112 protruding out of the first housing 1 in the third direction. The third direction is perpendicular to the first direction and perpendicular to the second direction.

That is, in the third direction, each separating plate 21 can completely block the plurality of first shielding plates 112 in its two adjacent groups of differential signal units, so as to ensure that all the groups of differential signal units can be grounded in common sufficiently to achieve the desired effect.

In some embodiments, the thickness of each separating sheet 21 at any position in the first direction is smaller than the gap between two adjacent first shielding sheets 112 in the first direction, so that the signal transmission effect is prevented from being affected by the contact between the separating sheet 21 and the first shielding sheets 112.

In some embodiments, the separation sheet 21 is provided with a plurality of convex pillars 211 spaced apart from each other along the second direction and arranged side by side, and an extending direction of each convex pillar 211 is parallel to the third direction. The third direction is perpendicular to the first direction and perpendicular to the second direction.

It can be understood that, in order to ensure that the separating plate 21 can interconnect all the differential signal unit groups together and does not affect the signal transmission of each differential signal unit 11, the separating plate 21 is designed to be thin, so that the protruding columns 211 arranged on each separating plate 21 can enhance the strength of the separating plate 21 to some extent and ensure the reliability of the separating plate 21.

Furthermore, each convex column 211 is not in contact with any first shielding sheet 112, so that the convex column 211 is prevented from being in contact with the first shielding sheet 112 to influence the signal transmission effect.

In some embodiments, in order to ensure that the protruding columns 211 can effectively increase the strength of the separating sheet 21, the height of any protruding column 211 in the third direction is greater than or equal to the relative height of any first shielding sheet 112 in the third direction and the first housing 1.

In some embodiments, the separating plate 21 further includes a plurality of small wave absorbing plates 4, two adjacent wave absorbing plates 4 are spliced by one of the convex columns 211, and a relative height of any wave absorbing plate 4 in the third direction with the first case 1 is greater than a relative height of any convex column 211 in the third direction with the first case 1.

In some embodiments, the wave-absorbing shell 2 further includes a shell body 22, two ends of each of the separating sheets 21 in the longitudinal direction are respectively fixedly connected to the shell body 22, and the shell body 22 is fixedly connected to the second shell 3.

It can be understood that, on the wave-absorbing shell 2, the plurality of separation sheets 21 can separate the plurality of differential signal unit groups, and the shell body 22 can fix the plurality of separation sheets 21 into a whole, thereby ensuring that the separation sheets 21 can effectively stand between two adjacent differential signal unit groups, and ensuring that all the differential signal unit groups can be effectively interconnected in the same ground.

In some embodiments, the absorbent shell 2 is an integrally formed shell of absorbent material. The wave-absorbing shell 2 formed integrally can be manufactured conveniently and assembled on a backplane connector conveniently.

Fig. 5 is a schematic structural diagram illustrating the assembly of the backplane connector into the backplane connector according to an embodiment of the present application.

In some embodiments, the backplane connector includes a contact portion, an intermediate portion, and a mounting portion. The contact part is used for being connected with a to-be-connected piece, the mounting part is used for being connected with another to-be-connected piece, and the middle part connects the contact part with the mounting part so as to transmit signals of the contact part and the mounting part. In this application, first casing 1, inhale ripples casing 2 and second casing 3 all set up in the contact site.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present disclosure, and the present disclosure should be construed as being covered by the claims and the specification. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.

Claims

1. A backplane connector, comprising:

the device comprises a first shell and a second shell embedded on the first shell;

the differential signal unit groups are arranged on the first shell at intervals along a first direction, each differential signal unit group comprises a plurality of differential signal units arranged along a second direction intersecting with the first direction, each differential signal unit comprises two differential signal pins and a first shielding sheet, and the first shielding sheet at least partially surrounds the two differential signal pins;

the wave-absorbing shell is embedded on the second shell and is fixedly connected with the first shell through the second shell; the wave-absorbing shell is at least partially blocked between two adjacent differential signal unit groups along the first direction, so that all the differential signal unit groups are connected in a common ground mode.

2. The backplane connector of claim 1, wherein the wave-absorbing housing comprises a plurality of spacers;

the plurality of separating sheets are arranged at intervals along the first direction, and a group of differential signal unit groups is arranged between every two adjacent separating sheets.

3. The backplane connector according to claim 2, wherein a height of each of the spacers in the third direction is greater than or equal to a height of any of the first shield pieces protruding from the first housing in the third direction;

wherein the third direction is perpendicular to the first direction and perpendicular to the second direction.

4. The backplane connector of claim 3, wherein a thickness of each of the spacers at any position in the first direction is smaller than a gap between two adjacent first shield pieces in the first direction.

5. The backplane connector of claim 4, wherein the spacer has a plurality of posts spaced apart from each other along the second direction and arranged side by side;

the extending direction of each convex column is parallel to the third direction.

6. The backplane connector of claim 5, wherein a height of any one of the posts in the third direction is greater than or equal to a relative height of any one of the first shielding plates with respect to the first housing in the third direction.

7. The backplane connector of any of claims 2-6, wherein the wave-absorbing housing further comprises a housing body;

every the both ends of parting slip along lengthwise direction are equallyd divide respectively with casing body fixed connection, casing body with second casing fixed connection.

8. The backplane connector of claim 7, wherein the wave-absorbing housing is an integrally formed wave-absorbing material housing.

9. The backplane connector of claim 1, wherein the first housing further has a plurality of second shield blades thereon;

the plurality of second shielding pieces are arranged along the first direction at intervals, and any one of the second shielding pieces and the plurality of first shielding pieces in one group of the differential signal unit groups are arranged in a row at intervals in the second direction;

each first shielding sheet is provided with an opening, and the openings of the first shielding sheets in the same row in the second direction face the second shielding sheets in the same row as the first shielding sheets in the same row.

10. The backplane connector of claim 9, wherein any of the first shield pieces located in the same row are located on the same side of the second shield pieces in the row in the second direction.