CN215181034U - Optical module - Google Patents

Abstract

The application provides an optical module, includes: the optical module comprises a circuit board, an optical submodule and a first flexible circuit board, wherein one end of the first flexible circuit board is electrically connected with the optical submodule, and the other end of the first flexible circuit board is electrically connected with the circuit board; the first flexible circuit board includes: a first substrate; the first metal layer is positioned on the first surface of the first substrate and comprises a high-speed signal line group and a first reference ground, the first reference ground is arranged on two sides of the high-speed signal line group, a first hollowed area is arranged on the first reference ground, and no metal is arranged in the first hollowed area; and the second metal layer is positioned on the second surface of the first base body and comprises a second reference ground, a second hollowed area is arranged on the second reference ground, and no metal is arranged in the second hollowed area. The application provides an optical module sets up first hollowed area and second hollowed area on first reference ground, second reference ground, reduces the area of laying the metal level on the first flexible circuit board, and then reduces flexible circuit board's rigidity, effectively avoids first flexible circuit board to meet with strong the bending and break.

Description

Optical module

Technical Field

The application relates to the technical field of optical fiber communication, in particular to an optical module.

Background

With the development of new services and application modes such as cloud computing, mobile internet, video and the like, the development and progress of the optical communication technology become increasingly important. In the optical communication technology, an optical module is a tool for realizing the interconversion of optical signals and is one of key devices in optical communication equipment, and the transmission rate of the optical module is continuously increased along with the development requirement of the optical communication technology.

At present, in order to improve the transmission rate of an optical module, transmission channels in the optical module may be increased, that is, transmission capacity is improved in the optical module through a multi-channel design, so as to achieve the purpose of improving the transmission rate of the optical module, and further, a multi-channel optical module such as a 2-channel optical module and a 4-channel optical module is emerging at present. With the increase of optical module transmission channels, in order to complete the packaging of the optical module, the optical transmit sub-module and the optical receive sub-module in the optical module are usually physically separated from the circuit board and are electrically connected to the circuit board through the flexible circuit board respectively.

However, the length of the flexible circuit board in the optical module is relatively short due to the limitation of the packaging size of the optical module, and the flexible circuit board is paved with relatively high-density signal routing lines and a reference ground, so that the flexible circuit board is prone to fracture when being subjected to strong bending in use, and further the optical module fails.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides an optical module for reducing the rigidity of a flexible circuit board and avoiding the flexible circuit board from breaking due to strong bending.

In a first aspect, the present application provides an optical module, including:

a circuit board;

the optical transmitter sub-module is used for generating signal light;

one end of the first flexible circuit board is electrically connected with the circuit board, and the other end of the first flexible circuit board is electrically connected with the light emission secondary module;

wherein the first flexible circuit board includes:

a first substrate;

the first metal layer is positioned on the first surface of the first substrate and comprises a high-speed signal line group and a first reference ground, the first reference ground is arranged on two sides of the high-speed signal line group, a first hollowed area is arranged on the first reference ground, and metal is not arranged in the first hollowed area;

the second metal layer is located on the second surface of the first base body and comprises a second reference ground, a second hollowed area is arranged on the second reference ground, and metal is not arranged in the second hollowed area.

The optical module comprises a circuit board and a light emission submodule, wherein the light emission submodule is electrically connected with the circuit board through a first flexible circuit board, and the first flexible circuit board comprises a first base body, a first metal layer positioned on a first surface of the first base body and a second metal layer positioned on a second surface of the first base body; the high-speed signal line group and a first reference ground are arranged on the first metal layer, the first reference ground is arranged on two sides of the high-speed signal line group, a first hollow area is arranged on the first reference ground, and no metal is arranged in the first hollow area; a second reference ground is arranged on the second metal layer, and a second hollowed area is arranged on the second reference ground. The first hollowed area is arranged on the first reference ground, and the second hollowed area is arranged on the second reference ground, so that the area of the metal layer laid on the first flexible circuit board is reduced on the basis of ensuring the requirement of the first flexible circuit board on the reference ground, and the rigidity of the flexible circuit board is further reduced, and the first flexible circuit board is prevented from being broken due to strong bending. Meanwhile, the first reference ground is arranged on two sides of the high-speed signal line group, and the shielding of high-speed signals among multiple channels can be realized by combining the second reference ground, so that the crosstalk of adjacent differential signals to the high-speed signals is reduced, and the influence on the performance of an optical module caused by the crosstalk of the high-speed signals of the multiple channels on the flexible circuit board is avoided.

In a second aspect, the present application provides an optical module, including: a circuit board;

the optical receiving sub-module is used for receiving signal light outside the optical module and converting the received signal light into a current signal;

one end of the second flexible circuit board is electrically connected with the light receiving sub-module, and the other end of the second flexible circuit board is connected with the circuit board;

wherein the second flexible circuit board includes:

a second substrate;

the third metal layer is positioned on the first surface of the second base body and comprises a third reference ground, a third hollowed area is arranged on the third reference ground, and no metal is arranged in the third hollowed area;

and the fourth metal layer is positioned on the second surface of the second substrate and comprises a high-speed signal line group and a fourth reference ground, the fourth reference ground is arranged on two sides of the high-speed signal line group, a fourth hollowed area is arranged on the fourth reference ground, and no metal is arranged in the fourth hollowed area.

The optical module comprises a circuit board and an optical receiving submodule, wherein the optical receiving submodule is electrically connected with the circuit board through a second flexible circuit board, and the second flexible circuit board comprises a second base body, a third metal layer positioned on a first surface of the second base body and a fourth metal layer positioned on a second surface of the first base body; a third reference ground is arranged on the third metal layer, and a third hollowed area is arranged on the third reference ground; and a high-speed signal line group and a fourth reference ground are arranged on the fourth metal layer, the fourth reference ground is arranged on two sides of the high-speed signal line group, a fourth hollow area is arranged on the fourth reference ground, and no metal is arranged in the fourth hollow area. The third hollowed area is arranged on the third reference ground, and the fourth hollowed area is arranged on the fourth reference ground, so that the area of the metal layer laid on the second flexible circuit board is reduced on the basis of ensuring the requirement of the first flexible circuit board on the reference ground, and the rigidity of the flexible circuit board is further reduced, and the second flexible circuit board is prevented from being broken due to strong bending. Meanwhile, the fourth reference ground is arranged on two sides of the high-speed signal line group, and the shielding of high-speed signals among multiple channels can be realized by combining the third reference ground, so that the crosstalk of adjacent differential signals to the high-speed signals is reduced, and the influence on the performance of an optical module caused by the crosstalk of the high-speed signals of the multiple channels on the flexible circuit board is avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of a connection relationship of an optical communication terminal;

FIG. 2 is a schematic diagram of an optical network unit;

fig. 3 is a schematic structural diagram of an optical module according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of an exploded structure of an optical module according to an embodiment of the present application;

fig. 5 is a cross-sectional view of an optical module according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of an electrical connection circuit board of the tosa and the rosa according to an embodiment of the present disclosure;

fig. 7 is a first schematic structural diagram of a first flexible circuit board according to an embodiment of the present disclosure;

fig. 8 is a second schematic structural diagram of a first flexible circuit board according to an embodiment of the present disclosure;

FIG. 9 is an enlarged view of a portion of FIG. 7 at A;

FIG. 10 is an enlarged view of a portion of FIG. 8 at B;

fig. 11 is an exploded view of an tosa and a flexible circuit board according to an embodiment of the present disclosure;

fig. 12 is a schematic structural diagram of a circuit board according to an embodiment of the present application.

Detailed Description

In order to facilitate the technical solution of the present application, some concepts related to the present application will be described below.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

One of the core links of optical fiber communication is the interconversion of optical and electrical signals. The optical fiber communication uses optical signals carrying information to transmit in information transmission equipment such as optical fibers/optical waveguides, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of light in the optical fibers/optical waveguides; meanwhile, the information processing device such as a computer uses an electric signal, and in order to establish information connection between the information transmission device such as an optical fiber or an optical waveguide and the information processing device such as a computer, it is necessary to perform interconversion between the electric signal and the optical signal.

The optical module realizes the function of interconversion of optical signals and electrical signals in the technical field of optical fiber communication, and the interconversion of the optical signals and the electrical signals is the core function of the optical module. The optical module is electrically connected with an external upper computer through a golden finger on an internal circuit board of the optical module, and the main electrical connection comprises power supply, I2C signals, data signals, grounding and the like; the electrical connection mode realized by the gold finger has become the mainstream connection mode of the optical module industry, and on the basis of the mainstream connection mode, the definition of the pin on the gold finger forms various industry protocols/specifications.

Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal. As shown in fig. 1, the connection of the optical communication terminal mainly includes the interconnection among the optical network terminal 100, the optical module 200, the optical fiber 101 and the network cable 103;

one end of the optical fiber 101 is connected with a far-end server, one end of the network cable 103 is connected with local information processing equipment, and the connection between the local information processing equipment and the far-end server is completed by the connection between the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is made by the optical network terminal 100 having the optical module 200.

An optical port of the optical module 200 is externally accessed to the optical fiber 101, and establishes bidirectional optical signal connection with the optical fiber 101; an electrical port of the optical module 200 is externally connected to the optical network terminal 100, and establishes bidirectional electrical signal connection with the optical network terminal 100; the optical module realizes the interconversion of optical signals and electric signals, thereby realizing the establishment of information connection between the optical fiber and the optical network terminal; specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input to the optical network terminal 100, and the electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module and input to the optical fiber.

The optical network terminal is provided with an optical module interface 102, which is used for accessing an optical module 200 and establishing bidirectional electric signal connection with the optical module 200; the optical network terminal is provided with a network cable interface 104, which is used for accessing the network cable 103 and establishing bidirectional electric signal connection with the network cable 103; the optical module 200 is connected to the network cable 103 through the optical network terminal 100, specifically, the optical network terminal transmits a signal from the optical module to the network cable and transmits the signal from the network cable to the optical module, and the optical network terminal serves as an upper computer of the optical module to monitor the operation of the optical module.

At this point, a bidirectional signal transmission channel is established between the remote server and the local information processing device through the optical fiber, the optical module, the optical network terminal and the network cable.

Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network terminal is an upper computer of the optical module, provides data signals for the optical module, and receives the data signals from the optical module, and the common upper computer of the optical module also comprises an optical line terminal and the like.

Fig. 2 is a schematic diagram of an optical network terminal structure. As shown in fig. 2, the optical network terminal 100 has a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting an electric port of an optical module such as a golden finger; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a projection such as a fin that increases a heat radiation area.

The optical module 200 is inserted into the optical network terminal, specifically, the electrical port of the optical module is inserted into the electrical connector inside the cage 106, and the optical port of the optical module is connected to the optical fiber 101.

The cage 106 is positioned on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged in the cage; the optical module is inserted into the cage, held by the cage, and the heat generated by the optical module is conducted to the cage 106 and then diffused by the heat sink 107 on the cage.

Fig. 3 is a schematic view of an optical module according to an embodiment of the present disclosure, and fig. 4 is a schematic view of an exploded structure of an optical module according to an embodiment of the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in an embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking member 203, a circuit board 300, a tosa 400, and a rosa 500.

The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the wrapping cavity is generally a square body, and specifically, the lower shell comprises a main plate and two side plates which are positioned at two sides of the main plate and are perpendicular to the main plate; the upper shell comprises a cover plate, and the cover plate covers two side plates of the upper shell to form a wrapping cavity; the upper shell can also comprise two side walls which are positioned at two sides of the cover plate and are perpendicular to the cover plate, and the two side walls are combined with the two side plates to realize that the upper shell covers the lower shell.

The two openings may be two ends (204, 205) in the same direction, or two openings in different directions; one opening is an electric port 204, and a gold finger of the circuit board extends out of the electric port 204 and is inserted into an upper computer such as an optical network terminal; the other opening is an optical port 205 for external optical fiber access to connect the tosa 400 and the rosa 500 inside the optical module; the photoelectric devices such as the circuit board 300 and the optical sub-module are positioned in the packaging cavity.

The assembly mode of combining the upper shell and the lower shell is adopted, so that the circuit board 300, the optical secondary module and other devices can be conveniently installed in the shells, and the upper shell and the lower shell form the outermost packaging protection shell of the optical module; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the housing of the optical module is not made into an integrated component, so that when devices such as a circuit board and the like are assembled, the positioning component, the heat dissipation component and the electromagnetic shielding component cannot be installed, and the production automation is not facilitated.

The unlocking component 203 is located on the outer wall of the wrapping cavity/lower shell 202, and is used for realizing the fixed connection between the optical module and the upper computer or releasing the fixed connection between the optical module and the upper computer.

The unlocking component 203 is provided with a clamping component matched with the upper computer cage; the end of the unlocking component can be pulled to enable the unlocking component to move relatively on the surface of the outer wall; the optical module is inserted into a cage of the upper computer, and the optical module is fixed in the cage of the upper computer by a clamping component of the unlocking component; by pulling the unlocking component, the clamping component of the unlocking component moves along with the unlocking component, so that the connection relation between the clamping component and the upper computer is changed, the clamping relation between the optical module and the upper computer is released, and the optical module can be drawn out from the cage of the upper computer.

The circuit board 300 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as an MCU, a laser driver chip, a limiting amplifier chip, a clock data recovery CDR, a power management chip, and a data processing chip DSP).

The circuit board connects the electrical appliances in the optical module together according to the circuit design through circuit wiring to realize the functions of power supply, electrical signal transmission, grounding and the like.

The chip on the circuit board 300 may be a multifunctional integrated chip, for example, a laser driver chip and an MCU chip are integrated into one chip, or a laser driver chip, a limiting amplifier chip and an MCU chip are integrated into one chip, and the chip is an integrated circuit, but the functions of the circuits do not disappear due to the integration, and only the circuit appears and changes, and the chip still has the circuit form. Therefore, when the circuit board is provided with three independent chips, namely, the MCU, the laser driver chip and the limiting amplifier chip, the scheme is equivalent to that when the circuit board 300 is provided with a single chip with three functions in one.

The circuit board is generally a hard circuit board, and the hard circuit board can also realize a bearing effect due to the relatively hard material of the hard circuit board, for example, the hard circuit board can stably bear a chip; when the optical transceiver is positioned on the circuit board, the rigid circuit board can also provide stable bearing; the hard circuit board can also be inserted into an electric connector in the upper computer cage, and specifically, a metal pin/golden finger is formed on the surface of the tail end of one side of the hard circuit board and is used for being connected with the electric connector; these are not easily implemented with flexible circuit boards.

A flexible circuit board is also used in a part of the optical module to supplement a rigid circuit board; the flexible circuit board is generally used in combination with a rigid circuit board, for example, the rigid circuit board may be connected to the optical transceiver device through the flexible circuit board.

As shown in fig. 4, the optical module provided in the embodiment of the present application includes a tosa 400 and a rosa 500, where the tosa 400 and the rosa 500 are collectively referred to as an optical sub-module; the tosa 400 and the rosa 500 are located at the edge of the circuit board 300, and the tosa 400 and the rosa 500 are stacked up and down. Optionally, the tosa 400 is closer to the upper housing 201 than the tosa 500, but not limited thereto, and the tosa 500 may be closer to the upper housing 201 than the tosa 400. The optical sub-assembly shown in fig. 3 and 4 is only an example of the present application, but the optical sub-assembly in the embodiment of the present application may also be a transceiver structure. Optionally, the optical sub-assembly is located at an end of the circuit board 300, and the optical sub-assembly is physically separated from the circuit board 300. The optical sub-assembly is connected to the circuit board 300 through a flexible circuit board.

Further, in the embodiment of the present application, the tosa 400 and the rosa 500 are physically separated from the circuit board 300, and are connected to the circuit board 300 through a flexible circuit board or an electrical connector.

When the tosa 400 is closer to the upper housing 201 than the rosa 500, the tosa 400 and the rosa 500 are disposed in the upper and lower housing forming package cavities. The lower case 202 may support the rosa 500; optionally, the lower housing 202 supports the rosa 500 through a spacer, and the rosa 500 supports the rosa 400. The optical module shown in fig. 3 and 4 is only an example in this application, and the optical sub-module in the optical module provided in this application may also adopt other structural forms such as an integral structure, so in this application embodiment, the optical sub-module may be electrically connected to the circuit board 300 through one flexible circuit board, and may also be electrically connected to the circuit board 300 through a plurality of flexible circuit boards. The optical sub-assembly is electrically connected to the circuit board 300 through a plurality of flexible circuit boards, which is taken as an example for the following description, and it is understood that if the optical sub-assembly is electrically connected to the circuit board 300 through one flexible circuit board, the optical sub-assembly is electrically connected to the circuit board 300 through a plurality of flexible circuit boards.

Fig. 5 is a cross-sectional view of an optical module according to an embodiment of the present disclosure, and fig. 5 shows an optical sub-module electrically connected to a circuit board 300 through a plurality of flexible circuit boards according to the embodiment of the present disclosure. As shown in fig. 5, in the embodiment of the present application, the flexible circuit boards include a first flexible circuit board 310, a second flexible circuit board 320, and a third flexible circuit board 330, the tosa 400 is electrically connected to the circuit board 300 through the first flexible circuit board 310 and the third flexible circuit board 330, the rosa 500 is electrically connected to the circuit board 300 through the second flexible circuit board 320, and the third flexible circuit board 330 is disposed between the first flexible circuit board 310 and the second flexible circuit board 320 at an interval.

In some embodiments of the present application, a high-speed signal line is disposed on the first flexible circuit board 310 for transmitting a high-speed signal between the circuit board 300 and the tosa 400, and the first flexible circuit board 310 transmits the high-speed signal to the tosa 400; a power line and other low-speed signal lines are arranged on the third flexible circuit board 330 and used for supplying power to the electrical devices in the tosa 400 through the circuit board 300; a high-speed signal line is arranged on the second flexible circuit board 320 and used for transmitting the high-speed current signal converted by the light-receiving sub-module 500 to the circuit board 300, and the light-receiving sub-module 500 transmits the high-speed signal to the circuit board 300 through the second flexible circuit board 320. Accordingly, the separation of high-speed signal transmission between the tosa 400, the rosa 500, and the circuit board 300 is achieved by the first and second flexible circuit boards 310 and 320. In addition, some power lines may also be arranged on the second flexible circuit board 320 as required, so that the circuit board 300 supplies power to the electrical devices in the rosa 500; alternatively, another flexible circuit, which routes low-speed signal lines such as power lines for the light receiving sub-module 500, may be provided between the second flexible circuit board 320 and the third flexible circuit board 330.

In a conventional optical module, a tosa and a rosa usually employ a flexible circuit board to connect a circuit board (for convenience of description, the flexible circuit board used for connecting the tosa and the circuit board is denoted as a flexible circuit board 1, and the flexible circuit board used for connecting the rosa and the circuit board is denoted as a flexible circuit board 2), and when the tosa 400 and the rosa 500 are stacked up and down, the flexible circuit board 1 and the flexible circuit board 2 are closer to each other (close to being arranged side by side); usually, the flexible circuit board is two-layer structure, the one deck is walked line and power routing layer for high speed, the one deck is the stratum, and then even the unified high-speed signal line that lays the transmitter optical subassembly and correspond in one side of flexible circuit board 2 of keeping away from at flexible circuit board 1, the stratum is unified to lay at the opposite side of flexible circuit board 1, the received signal line that flexible circuit board 2 laid is walked line and power routing layer with flexible circuit board 1's high speed and is only kept apart one deck ground, hardly play good isolation effect to the radiation that multichannel high-speed signal produced.

Compared with the arrangement of the flexible circuit boards in the conventional optical module, the optical module provided in the embodiment of the present application is arranged between the first flexible circuit board 310 and the third flexible circuit board 330 through the second flexible circuit board 320, the second flexible circuit board 320 at least includes a power line and a ground layer, and the first flexible circuit board 310 and the second flexible circuit board 320 are isolated by the third flexible circuit board 330, so that the radiation crosstalk generated between the high-speed signal on the first flexible circuit board 310 and the high-speed signal on the second flexible circuit board 320 is shielded through the third flexible circuit board 330, and the error rate caused by the radiation crosstalk generated by the high-speed signals to the optical receiving signals is favorably reduced. In the embodiment of the present application, the third flexible circuit board 330 may also be a flexible circuit board for connecting the rosa 500 and the circuit board 300.

Meanwhile, when the rosa is connected to the circuit board only through the flexible circuit board 1, if the rosa includes a plurality of paths, such as 4, 8, etc., the number of the high-speed signal lines, the power lines, etc. will reach dozens, if the dozens of lines are arranged side by side on the flexible circuit board 1, a relatively wide flexible circuit board 1 may be needed, and further, the layout of the circuit board will be tense. In the optical module provided by the embodiment of the present application, the first flexible circuit board 310 and the third flexible circuit board 330 share the layout requirement of the flexible circuit board 1, which is beneficial to releasing the tension layout for connection between the tosa and the circuit board, and is convenient to promote the development of multiple channels of the optical module to a certain extent.

Fig. 6 is a schematic structural diagram of an electrical connection circuit board for an tosa and an rosa according to an embodiment of the present disclosure. As shown in fig. 6, the tosa 400 is stacked above the rosa 500; one end of the first flexible circuit board 310 is electrically connected with the tosa 400, the other end is electrically connected with the circuit board 300, one end of the third flexible circuit board 330 is electrically connected with the tosa 400, the other end is electrically connected with the circuit board 300, the tosa 400 is further electrically connected with the circuit board 300 through the first flexible circuit board 310 and the third flexible circuit board 330, and the first flexible circuit board 310 is arranged above the third flexible circuit board 330; one end of the second flexible circuit board 320 is electrically connected to the light receiving module 500, and the other end is electrically connected to the circuit board 300, the light receiving sub-module 500 is electrically connected to the circuit board 300 through the second flexible circuit board 320, and the second flexible circuit board 320 is disposed under the third flexible circuit board 330, so that the third flexible circuit board 330 is disposed between the first flexible circuit board 310 and the second flexible circuit board 320 at intervals. Of course, if the rosa 500 is stacked on the rosa 400, the third flexible circuit board 330 is disposed between the first flexible circuit board 310 and the second flexible circuit board 320 by disposing the second flexible circuit board 320 above the third flexible circuit board 330 and disposing the first flexible circuit board 310 below the third flexible circuit board 330.

As shown in fig. 6, the distances between the tosa 400 and the tosa 500 and the circuit board 300 are relatively short due to the size of the optical module, and the flexible circuit board between the tosa 400 and the tosa 500 and the circuit board 300 has a bend with a large radian as shown in fig. 6, so when the stiffness of the flexible circuit board reaches a certain range, the flexible circuit board is easily broken when the flexible circuit board is connected or the tosa 400 and the tosa 500 are assembled. In order to reduce the rigidity of the flexible circuit board and avoid the flexible circuit board from breaking due to strong bending, the present application further provides a flexible circuit board with a novel structure, and the following description of the flexible circuit board with the novel structure is given by taking the first flexible circuit board 310 as an example.

Fig. 7 is a first structural schematic diagram of a first flexible circuit board provided in the embodiment of the present application, fig. 8 is a second structural schematic diagram of the first flexible circuit board provided in the embodiment of the present application, fig. 7 shows a first surface structure of the first flexible circuit board, and fig. 8 shows a second surface structure of the first flexible circuit board. As shown in fig. 7 and 8, the first flexible circuit board 310 provided in the embodiment of the present application includes a first substrate 311, a first metal layer 312 on a first surface of the first substrate 311, and a second metal layer 313 on a second surface of the first substrate 311. Wherein: the first metal layer 312 is provided with a high-speed signal line group 3121 and a first reference ground 3122, the first reference ground 3122 is provided at both sides of the high-speed signal line group 3121, and thus, different high-speed signal line groups 3121 may be separated by the first reference ground 3122; a first hollowed-out area 3123 is provided on the first reference ground 3122, no metal is provided in the first hollowed-out area 3123, that is, the first metal layer 312 is hollowed out at the location of the first hollowed-out area 3123; a second reference ground 3131 is disposed on the second metal layer 313, a second hollowed-out area 3132 is disposed on the second reference ground 3131, and no metal is disposed in the second hollowed-out area 3132, i.e., the second metal layer 313 is hollowed out at the position of the second hollowed-out area 3132. In the embodiment of the application, the first base body takes polyimide or polyester film as a base material.

In the first flexible circuit board 310 provided in this embodiment, the high-speed signal line group 3121, the first reference ground 3122 and the first hollowed area 3123 are disposed on the first metal layer 312, the first hollowed area 3123 is located on the first reference ground 3122, and thus an area of the first reference ground 3122 for laying the metal layer is reduced by the first hollowed area 3123; a second reference ground 3131 and a second hollowed-out region 3132 are disposed on the second metal layer 313, the second hollowed-out region 3132 is located in the second reference ground 3131, and an area of the second reference ground 3131 where the metal layer is laid is further reduced by the second hollowed-out region 3132. In the first flexible circuit board 310 provided in this embodiment, the first reference ground 3122 is used to provide the first hollowed area 3123, and the second hollowed area 3132 is provided on the second reference ground 3131, so as to reduce the area of the metal layer laid on the first flexible circuit board 310, and further reduce the rigidity of the first flexible circuit board, so as to prevent the first flexible circuit board 310 from breaking due to strong bending. In some embodiments of the present application, the first hollowed area 3123 and the second hollowed area 3132 should be uniformly disposed on the corresponding first reference ground 3122 and the second reference ground 3131 to ensure the same rigidity of each portion of the first flexible circuit board 310 as much as possible, such as disposing the first hollowed area 3123 at a middle position corresponding to the first reference ground 3122 and disposing the second hollowed area 3132 at a middle position corresponding to the second reference ground 3131. In addition, the first references 3122 are arranged on two sides of the high-speed signal line group 3121, and then the shielding of high-speed signals among multiple channels can be realized by combining the second reference ground 3131, so that crosstalk of adjacent differential signals to the high-speed signals is reduced, and the influence on the performance of the optical module due to crosstalk of the high-speed signals of the multiple channels on the flexible circuit board is avoided. As shown in fig. 7, the high-speed signal line group 3121 may include a pair of signal high-speed signal traces, and may also include one signal high-speed signal trace, which may be selected according to actual needs.

Fig. 9 is a partially enlarged view of a portion a in fig. 7, fig. 10 is a partially enlarged view of a portion B in fig. 8, and fig. 9 and 10 show a detailed structure of the first flexible circuit board 310 according to an embodiment of the present disclosure. As shown in fig. 9 and 10, in some embodiments of the present application, a projection of the second reference ground 3131 in the direction of the first surface of the first substrate 311 covers the high-speed signal line group 3121, and the high-speed signal line group 3121 is surrounded by the first reference grounds 3122 on the left and right sides and the second reference ground 3131 below the first reference grounds, so that shielding of high-speed signals between multiple channels can be performed, and crosstalk between adjacent high-speed signal line groups 3121 is reduced. Furthermore, the wiring line width of the first reference ground 3122 is greater than the wiring line width of the high-speed signal line group 3121, so that crosstalk between adjacent high-speed signal line groups 3121 can be reduced, and the shielding performance of high-speed signals among multiple channels is ensured.

As shown in fig. 9 and 10, in some embodiments of the present application, a projection of the second reference land 3131 in the direction of the first surface of the first base 311 covers the first reference land 3122, and several through holes 314 are disposed on an overlapped area between the second reference land 3131 and the first reference land 3122, through which the first reference land 3122 and the second reference land 3131 are correspondingly connected. In this way, in the present embodiment, the via 314 is used to combine the first reference ground 3122 and the second reference ground 3131 to shield the inter-lane high-speed signals on the first flexible circuit board 310, which is more convenient for reducing the crosstalk between the adjacent high-speed signal line groups 3121 on the first flexible circuit board 310. In some embodiments of the present application, the vias 314 are distributed on two sides of the first hollowed-out area 3123, for example, the vias 314 are uniformly distributed on two sides of the first hollowed-out area 3123.

As shown in fig. 9 and 10, in some embodiments of the present application, a projection of the second hollowed-out area 3132 in the direction of the first surface of the first substrate 311 covers the first hollowed-out area 3123, so that the projection of the second hollowed-out area 3132 and the projection of the first hollowed-out area 3123 in the direction of the first substrate 311 are overlapped as much as possible. Further, the projections of the second cut-out region 3132 in the first surface direction of the first base 311 overlap with the second cut-out region 3132. Therefore, the rigidity of each part of the first flexible circuit board 310 can be relatively uniform, and the first flexible circuit board 310 is prevented from being broken due to strong bending.

In the embodiment of the present application, the second flexible circuit board 320 includes a second substrate, a third metal layer disposed on a first side of the second substrate, and a fourth metal layer disposed on a second side of the second substrate. Wherein: a third hollowed area is arranged on the third metal layer, and no metal is arranged in the third hollowed area, namely, the third metal layer is hollowed at the position of the third hollowed area; a high-speed signal line group and a fourth reference ground are arranged on the fourth metal layer, the fourth reference ground is arranged on two sides of the high-speed signal line group, and different high-speed signal line groups on the second flexible circuit board 320 are separated by the fourth reference ground; and a fourth hollowed area is arranged on the fourth reference ground, and no metal is arranged in the fourth hollowed area, namely, the fourth metal layer is hollowed in the fourth hollowed area. In the second flexible circuit board 320 provided by this embodiment, the third hollowed area on the third reference ground and the fourth hollowed area on the fourth reference ground are used to reduce the area of the metal layer laid on the second flexible circuit board 320, so as to reduce the rigidity of the second flexible circuit board, thereby preventing the second flexible circuit board 320 from being broken due to strong bending.

In some embodiments of the present application, the projection of the third reference ground in the direction of the second surface of the first substrate covers the high-speed signal line group on the second flexible circuit board 320, and the high-speed signal line group on the second flexible circuit board 320 is surrounded by the fourth reference grounds on the left and right sides and the third reference ground above the fourth reference grounds, so that the shielding of high-speed signals between multiple channels on the second flexible circuit board 320 can be performed, and crosstalk between adjacent high-speed signal line groups is reduced.

In some embodiments of the present application, a projection of the third reference ground in the direction of the second surface of the first substrate covers the fourth reference ground, and a plurality of via holes are disposed on a coinciding region between the third reference ground and the fourth reference ground, through which the third reference ground and the fourth reference ground are correspondingly connected. In this way, in the present embodiment, the via holes are combined with the third reference ground and the fourth reference ground to shield the inter-multi-channel high-speed signals on the second flexible circuit board 320, so as to further reduce crosstalk between adjacent high-speed signal line groups on the second flexible circuit board 320.

In some embodiments of the present application, a projection of the third hollow area in the direction of the second surface of the second substrate covers the fourth hollow area, so that the projection of the third hollow area and the projection of the fourth hollow area in the direction of the second substrate are as coincident as possible. Therefore, the rigidity of each part of the second flexible circuit board 320 can be uniform, and the second flexible circuit board 320 is prevented from being broken due to strong bending.

For a more detailed structural description and advantageous effects of the second flexible circuit board 320 in the embodiment of the present application, reference may be made to the description of the first flexible circuit board 310 in the embodiment of the present application.

The first flexible circuit board 330 provided in the embodiment of the present application includes a third substrate, a fifth metal layer disposed on a first surface of the third substrate, and a sixth metal layer disposed on a second surface of the third substrate. Wherein: the fifth metal layer is provided with a low-speed signal line group and a fifth reference ground, and the fifth reference ground is arranged on two sides of the low-speed signal line group; a fifth hollowed area is arranged on the fifth reference ground, and no metal is arranged in the fifth hollowed area, namely, the fifth metal layer is hollowed at the position of the fifth hollowed area; and a sixth reference ground is arranged on the sixth metal layer, a sixth hollowed area is arranged on the sixth reference ground, and no metal is arranged in the sixth hollowed area, namely the sixth metal layer is hollowed at the position of the sixth hollowed area. In the third flexible circuit board 330 provided in this embodiment, the fifth hollowed area is disposed on the fifth reference ground, and the fifth hollowed area is disposed on the fifth reference ground, so that the area of the metal layer laid on the third flexible circuit board 330 is reduced, and the rigidity of the third flexible circuit board 330 is further reduced, so as to prevent the third flexible circuit board 330 from being broken due to strong bending.

For a more detailed structural description and advantageous effects of the third flexible circuit board 330 in the embodiment of the present application, reference may be made to the description of the first flexible circuit board 310 in the embodiment of the present application.

Fig. 11 is an exploded schematic view of an optical sub-assembly and a flexible circuit board according to an embodiment of the present disclosure. As shown in fig. 11, in the optical module provided in the embodiment of the present application, the tosa 400 includes an electrical connector 420 thereon, the tosa 400 connects the first flexible circuit board 310 and the third flexible circuit board 330 through the electrical connector 420, and the electrical connector 420 facilitates electrical connection with the first flexible circuit board 310 and the third flexible circuit board 330. Optionally, a boss 421 is disposed at one end of the electrical connector 420, which is used for connecting the first flexible circuit board 310 and the third flexible circuit board 330, the boss 421 includes a first connection surface 4211 and a second connection surface 4212, and pads are respectively disposed on the first connection surface 4211 and the second connection surface 4212 correspondingly; one end of the first flexible circuit board 310 is soldered to the first connection surface 4211, and one end of the third flexible circuit board 330 is soldered to the second connection surface 4212. By arranging the boss 421 on the electrical connector 420, the first connection surface 4211 and the second connection surface 4212 form steps with the top surface and the bottom surface of the electrical connector 420, respectively, and the steps can be used for limiting the end portions of the first flexible circuit board 310 and the third flexible circuit board 330, so that the first flexible circuit board 310 and the third flexible circuit board 330 can be more conveniently connected with the electrical connector 420 by welding.

In the embodiment of the present application, an opening 520 is disposed on the light receiving sub-module 500, that is, the opening 520 is disposed on the cavity of the light receiving sub-module 500, and one end of the second flexible circuit board 320 is inserted into the opening 520. One end of the second flexible circuit board 320 is inserted into and fixed in the cavity of the optical receive sub-module 500 to be electrically connected to the optical receive chip, the transimpedance amplifier, and other electrical devices, and the other end of the second flexible circuit board 320 is used for being electrically connected to the circuit board 300.

Fig. 12 is a schematic structural diagram of a circuit board according to an embodiment of the present application. As shown in fig. 12, the top surface of the circuit board 300 is provided with a first land 341, a second land 343, and a third land 342, the first land 341, the second land 343, and the third land 342 are arranged at the end portion of the circuit board 300, and the second land 343 is located at the leftmost end of the end portion of the circuit board 300. Among them, the first land 341 is used to solder-connect the other end of the first flexible circuit board 310, the second land 343 is used to solder-connect the other end of the second flexible circuit board 320, and the third land 342 is used to solder-connect the other end of the third flexible circuit board 330. The first bonding pad 341, the second bonding pad 343, and the third bonding pad 342 are disposed on the same surface of the circuit board 300 and are disposed at the end of the circuit board 300, which is beneficial to improving the utilization of the layout on the circuit board 300 and improving the space utilization of the circuit board 300. In the embodiment of the present application, the first land 341, the second land 343, and the third land 342 are not limited to the end portions provided at the top surface of the circuit board 300, and may be provided at the end portions of the bottom surface of the circuit board 300. The first, second, and third lands 341, 343, and 342 are disposed on the same side of the circuit board 300, and also facilitate soldering of the first, second, and third flexible circuit boards 310, 320, and 330.

Further, the high speed signal lines are routed on the top and bottom surfaces of the circuit board 300, respectively, i.e., the high speed signal lines directly electrically connected to the first lands 341 are routed on the top surface of the circuit board 300 and the high speed signal lines electrically connected to the third lands 342 are routed on the bottom surface of the circuit board 300, and then the high speed signal lines routed on the bottom surface of the circuit board 300 are electrically connected to the third lands 342 through vias. Of course, in the present application, it is also possible to provide the third land 342 on the bottom surface of the circuit board 300, and the second land 343 on the bottom surface of the circuit board 300. Further, in the present application, the first bonding pad 341 and the third bonding pad 342 may be located on different surfaces of the circuit board 300, and the second bonding pad 343 may be located on the same surface of the circuit board 300 as the first bonding pad 341 or on the same surface of the circuit board 300 as the third bonding pad 342.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit 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 technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims (10)

1. A light module, comprising:

a circuit board;

the optical transmitter sub-module is used for generating signal light;

one end of the first flexible circuit board is electrically connected with the light emission secondary module, and the other end of the first flexible circuit board is connected with the circuit board;

wherein the first flexible circuit board includes:

a first substrate;

the first metal layer is positioned on the first surface of the first substrate and comprises a high-speed signal line group and a first reference ground, the first reference ground is arranged on two sides of the high-speed signal line group, a first hollowed area is arranged on the first reference ground, and metal is not arranged in the first hollowed area;

the second metal layer is located on the second surface of the first base body and comprises a second reference ground, a second hollowed area is arranged on the second reference ground, and metal is not arranged in the second hollowed area.

2. The optical module of claim 1, wherein a projection of the second reference ground in a direction of the first surface of the first substrate covers the first reference ground;

the flexible circuit board further comprises a via hole which is connected with the first reference ground and the second reference ground in a penetrating mode.

3. The optical module according to claim 1, wherein a projection of the first cutout region in the direction of the second surface of the first substrate covers the second cutout region.

4. The light module of claim 1, further comprising:

the optical receiving sub-module is used for receiving signal light outside the optical module and converting the received signal light into a current signal;

one end of the second flexible circuit board is electrically connected with the light receiving sub-module, and the other end of the second flexible circuit board is connected with the circuit board;

wherein the second flexible circuit board includes:

a second substrate;

the third metal layer is positioned on the first surface of the second base body and comprises a third reference ground, a third hollowed area is arranged on the third reference ground, and no metal is arranged in the third hollowed area;

and the fourth metal layer is positioned on the second surface of the second substrate and comprises a high-speed signal line group and a fourth reference ground, the fourth reference ground is arranged on two sides of the high-speed signal line group, a fourth hollowed area is arranged on the fourth reference ground, and no metal is arranged in the fourth hollowed area.

5. The optical module of claim 2, wherein the vias are distributed on both sides of the first hollowed area.

6. The optical module of claim 1, wherein a first reference ground trace line width on both sides of the first hollow area is greater than the high-speed signal line group trace line width.

7. The optical module according to claim 1, wherein a projection of the first cutout region in the direction of the second surface of the first substrate coincides with the second cutout region.

8. The light module of claim 4, wherein a projection of the third reference ground in the direction of the second surface of the first base covers the fourth reference ground;

the second flexible circuit board further comprises a via hole which is connected with the third reference ground and the fourth reference ground in a penetrating manner;

the projection of the third hollowed-out area in the direction of the second surface of the second substrate covers the fourth hollowed-out area.

9. The optical module of claim 4, further comprising a third flexible circuit board, one end of which is electrically connected to the tosa and the other end of which is electrically connected to the circuit board;

the third flexible circuit board includes:

a third substrate;

the fifth metal layer is positioned on the first surface of the third base body and comprises a low-speed signal line group and a fifth reference ground, the fifth reference ground is arranged on two sides of the low-speed signal line group, a fifth hollowed area is arranged on the fifth reference ground, and metal is not arranged in the fifth hollowed area;

and the sixth metal layer is positioned on the second surface of the third base body and comprises a sixth reference ground, a sixth hollowed area is arranged on the sixth reference ground, and no metal is arranged in the sixth hollowed area.

10. A light module, comprising:

a circuit board;

the optical receiving sub-module is used for receiving signal light outside the optical module and converting the received signal light into a current signal;

one end of the second flexible circuit board is electrically connected with the light receiving sub-module, and the other end of the second flexible circuit board is connected with the circuit board;

wherein the second flexible circuit board includes:

a second substrate;

the third metal layer is positioned on the first surface of the second base body and comprises a third reference ground, a third hollowed area is arranged on the third reference ground, and no metal is arranged in the third hollowed area;

and the fourth metal layer is positioned on the second surface of the second substrate and comprises a high-speed signal line group and a fourth reference ground, the fourth reference ground is arranged on two sides of the high-speed signal line group, a fourth hollowed area is arranged on the fourth reference ground, and no metal is arranged in the fourth hollowed area.

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