CN215186761U - Optical module - Google Patents

Abstract

The application discloses optical module includes: the upper shell and the lower shell cover a wrapped cavity formed by covering, and a circuit board arranged in the wrapped cavity. The circuit board includes: a top layer and a middle layer. The top layer is provided with a signal golden finger and a grounding golden finger, wherein the signal golden finger is used for transmitting signals, and the grounding golden finger is arranged on one side of the signal golden finger and used for backflow of the signals in the signal golden finger. The circuit board is internally provided with a buried hole which is positioned in the projection area of the grounding golden finger, one end of the buried hole is connected with the grounding golden finger, and the other end of the buried hole is connected with the grounding wire of the middle layer. This application is through setting up the buried hole below the ground connection golden finger, connects the earth connection of top layer and intermediate level, increases the ground connection signal backflow route of ground connection golden finger to buried hole to intermediate level, reduces high frequency loss, is favorable to improving high frequency.

Description

Optical module

Technical Field

The application relates to the technical field of 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.

With the increasing of the speed of the optical module, the single link speed of the optical module is gradually increased, and the high-frequency loss is increased.

SUMMERY OF THE UTILITY MODEL

The application provides an optical module to reduce optical module communication loss.

In order to solve the technical problem, the embodiment of the application discloses the following technical scheme:

the embodiment of the application discloses an optical module, includes: an upper housing;

the lower shell is covered with the lower shell to form a wrapping cavity;

the circuit board is arranged in the packaging cavity and comprises a top layer and a middle layer;

one end of top layer is equipped with the golden finger, include:

one end of the signal golden finger is connected with the functional chip;

the grounding golden finger is arranged on one side of the signal golden finger and is used for the backflow of signals in the signal golden finger;

the circuit board is internally provided with a buried hole which is positioned in the projection area of the grounding golden finger, one end of the buried hole is connected with the grounding golden finger, and the other end of the buried hole is connected with the grounding wire of the middle layer.

Compared with the prior art, the beneficial effect of this application is:

the application discloses optical module includes: the upper shell and the lower shell cover a wrapped cavity formed by covering, and a circuit board arranged in the wrapped cavity. The circuit board includes: a top layer and a middle layer. The top layer is provided with a signal golden finger and a grounding golden finger, wherein the signal golden finger is used for transmitting signals, and the grounding golden finger is arranged on one side of the signal golden finger and used for backflow of the signals in the signal golden finger. The circuit board is internally provided with a buried hole which is positioned in the projection area of the grounding golden finger, one end of the buried hole is connected with the grounding golden finger, and the other end of the buried hole is connected with the grounding wire of the middle layer. This application is through setting up the buried hole below the ground connection golden finger, connects the earth connection of top layer and intermediate level, increases the ground connection signal backflow route of ground connection golden finger to buried hole to intermediate level, reduces high frequency loss, is favorable to improving high frequency.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

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

fig. 2 is a schematic structural diagram of an optical network terminal;

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

fig. 4 is an exploded structural diagram of an optical module according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a circuit board structure according to an embodiment of the present application;

fig. 6 is a schematic diagram of an upper surface structure of a circuit board according to an embodiment of the present disclosure;

fig. 7 is a first schematic cross-sectional view illustrating a circuit board structure according to an embodiment of the present disclosure;

FIG. 8 is a schematic view of a portion of the structure of FIG. 6;

fig. 9 is a schematic cross-sectional view of a circuit board according to an embodiment of the present disclosure;

fig. 10 is another schematic cross-sectional view taken along the line a-a in fig. 8.

Detailed Description

In order to explain the technical solution of the application, some concepts related to the application are first described below.

In this specification, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such circuit structure, article, or apparatus. Without further limitation, the presence of an element identified by the phrase "comprising an … …" does not exclude the presence of other like elements in a circuit structure, article or device comprising the element.

In order to make those skilled in the art better understand the technical solutions in the present application, 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 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 information, 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 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 mutual conversion 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 via 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 100, specifically, an electrical port of the optical module is inserted into an electrical connector inside the cage 106, and an 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 the embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking member 203, a circuit board 300, and an optical transceiver module.

The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the packaging cavity generally presents a square body. Specifically, the lower housing 202 includes a main board and two side boards located at two sides of the main board and arranged perpendicular to the main board; 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 may further include two side walls disposed at two sides of the cover plate and perpendicular to the cover plate, and the two side walls are combined with the two side plates to cover the upper shell 201 on the lower shell 202.

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 an optical transceiver module inside the optical module; the photoelectric devices such as the circuit board 300 and the optical transceiver 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 transceiver 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 module; the upper shell and the lower shell are made of metal materials generally, electromagnetic shielding and heat dissipation are achieved, the shell of the optical module cannot be made into an integral component generally, and therefore when devices such as a circuit board are assembled, the positioning component, the heat dissipation component and the electromagnetic shielding component cannot be installed, and production automation is not facilitated.

The unlocking component 203 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 300 connects the electrical devices in the optical module together according to the circuit design through circuit wiring to realize the electrical functions of power supply, electrical signal transmission, grounding and the like.

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 component 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.

The golden finger end of the circuit board is positioned at the electric port and is connected with the upper computer to realize communication. The golden finger is connected with each functional chip on the circuit board through the circuit wiring.

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 module by using the flexible circuit board.

The optical transceiver module includes two parts, namely an optical transmitter 400 and an optical receiver, which are respectively used for transmitting and receiving optical signals. The light emitting device generally comprises a light emitter, a lens and a light detector, wherein the lens and the light detector are respectively positioned on different sides of the light emitter, light beams are respectively emitted from the front side and the back side of the light emitter, and the lens is used for converging the light beams emitted from the front side of the light emitter so that the light beams emitted from the light emitter are converging light to be conveniently coupled to an external optical fiber; the optical detector is used for receiving the light beam emitted by the reverse side of the optical emitter so as to detect the optical power of the optical emitter. Specifically, light emitted by the light emitter enters the optical fiber after being converged by the lens, and the light detector detects the light emitting power of the light emitter so as to ensure the constancy of the light emitting power of the light emitter.

Fig. 5 is a schematic diagram of a circuit board structure according to an embodiment of the present application. Fig. 6 is a schematic diagram of an upper surface structure of a circuit board according to an embodiment of the present disclosure. Fig. 6 is a schematic diagram of the circuit board without electrical devices connected thereto. Referring to fig. 5 and 6, a plurality of functional chips 600 are disposed on the surface of the circuit board 300, a gold finger 500 is disposed at one end of the circuit board 300, and the functional chips 600 in the optical module are connected together according to circuit design by circuit routing to implement power supply, electrical signal transmission, grounding and other electrical functions.

The functional chip 600 is connected with the golden finger 500 through a signal line, and the adjacent side of the signal line is provided with a grounding wire 320 to realize signal backflow. Along with the gradual improvement of the communication frequency of the optical module, a signal backflow path is increased, so that the loss is reduced, and the frequency is improved.

In order to realize power supply, signal transmission and the like of various chips, the circuit board 300 is of a multi-layer plate structure, different circuit wires are laid on each metal layer respectively, and then the golden finger on the top layer is guided by signals through via holes arranged between different plate layers and then connected with the outside through the golden finger.

At the present stage, in order to realize signal backflow of the golden finger, grounding golden fingers are arranged on two sides of the signal golden finger, one end of a grounding wire connected with the grounding golden finger is connected to the grounding layer of the whole board through a grounding through hole formed in the PCB, so that signal backflow at the position of the grounding golden finger needs to reach the position of the grounding through hole of the signal circuit through the whole golden finger, and then the signal backflow is realized through connection of the grounding through hole and the grounding layer, and the backflow path of a transmission signal is longer, so that loss is easily caused.

In order to solve the above problem, an embodiment of the present application provides a circuit board, where a differential signal line 310 is disposed on a top layer, and a differential signal golden finger 520 is disposed at one end of the differential signal line 310 and is used for being connected with an upper computer. The top ground line 320 is disposed on one side of the differential signal line 310, one end of the top ground line 320 is connected to the grounding gold finger 510, and the grounding gold finger 510 is disposed adjacent to the differential signal gold finger 520. A plurality of buried holes are formed in the circuit board corresponding to the grounding gold finger 510, one end of each buried hole is connected with the grounding gold finger 510 but does not penetrate through the grounding gold finger, and the other end of each buried hole is connected with a grounding layer inside the circuit board. The signal return path of the differential signal gold finger 520 is increased from the grounding gold finger 510 to the buried via, and then through the internal grounding layer of the circuit board connected with the buried via, the grounding connection is realized through the internal grounding layer. The signal return path of the differential signal golden finger 520 part is increased, which is beneficial to reducing loss and improving signal frequency.

Fig. 7 is a first schematic cross-sectional view of a circuit board structure according to an embodiment of the present disclosure. Referring to fig. 6 and 7, in the embodiment of the present application, taking an eight-layer board as an example, the circuit board 300 includes: the laminated board comprises a first board layer 301, a second board layer 302, a third board layer 303, a fourth board layer 304, a fifth board layer 305, a sixth board layer 306, a seventh board layer 307 and an eighth board layer 308 which are sequentially laminated, wherein a dielectric layer is filled between every two adjacent board layers, and the dielectric layer is made of an insulating material, for example, is filled with glass fiber or epoxy resin and other media. The plies are metal plies, typically copper plies.

In some embodiments provided herein, the outermost plies are referred to as top and bottom plies, and the other plies are referred to as intermediate plies 309, such that the intermediate plies in this embodiment include second ply 302, third ply 303, fourth ply 304, fifth ply 305, sixth ply 306, and seventh ply 307. To increase signal return, each slab is provided with GND (ground signal).

Fig. 8 is a schematic view of a portion of the structure of fig. 6. Referring to fig. 8, in some embodiments provided herein, the first board layer 301, also referred to as the top layer, is provided with a differential signal line 310, a top layer ground line 320, and a gold finger 500. Specifically, the positive differential signal line 311, the negative differential signal line 312, the first sub-ground line 321, and the second sub-ground line 322 are disposed on the surface of the first board layer, wherein the first sub-ground line 321 and the second sub-ground line 322 are disposed on two sides of the positive differential signal line 311 and the negative differential signal line 312, respectively. One end of the first sub-ground line 321 is provided with a first grounding golden finger 511, one end of the second sub-ground line 322 is provided with a second grounding golden finger 512, one end of the positive differential signal line 311 is provided with a positive signal golden finger 521, and one end of the negative differential signal line 312 is provided with a negative signal golden finger 522. The first grounding finger 511 and the second grounding finger 512 are disposed between the positive signal finger 521 and the negative signal finger 522. As shown, the positive signal gold finger 521 is disposed between the first grounding gold finger 511 and the negative signal gold finger 522, and the negative signal gold finger 522 is disposed between the positive signal gold finger 521 and the second grounding gold finger 512.

For the convenience of being connected of golden finger and host computer, the one end of golden finger is located the tip that is close to the circuit board, for the convenience of expression, the one end that is close to circuit board tip with the golden finger is called the end in this application, and the other end is called the top.

Generally, the distance from the end of the positive signal gold finger 521 to the end of the circuit board is greater than the distance from the end of the first grounding gold finger 511 to the end of the circuit board from the end of the second grounding gold finger 512, and the grounding gold fingers form a half-enclosed structure with the positive signal gold finger 521 and the negative signal gold finger 522, which is beneficial to shortening the signal return path and reducing the loss.

The circuit board 300 is further provided with a plurality of buried holes below the first grounding gold fingers 511. Different board layers within the circuit board 300 are typically used to implement different circuit connections, and then connections between the circuitry of the inner board layer and the gold fingers of the first board layer are made through buried vias between the layers.

In order to reduce the signal return path of the positive signal gold finger 521 portion, in the embodiment of the present application, a first sub-return-flow hole set 530 is disposed on the circuit board 300 and located in the projection area of the first grounding gold finger 511 in the middle layer. One end of the first sub-via group 530 is connected to the first grounding gold finger 511, and the other end is connected to the GND of the middle layer, for connecting the first grounding gold finger 511 with the ground signal line of the middle layer 309.

The return path of the signal of the positive signal gold finger 521 is changed from the original return path through the first grounding gold finger 511 to the return path through the first grounding gold finger 511, the first grounding gold finger 511 to the first sub-return hole group 530 to the ground layer, so that the signal return path is increased, and the loss is reduced.

One end of the first sub-reflow hole group 530 is connected to the first ground gold finger 511, and the other end is connected to the GND of the intermediate layer 309, that is, the other end of the first sub-reflow hole group 530 may be connected to the GND of any one or more of the second board layer 302, the third board layer 303, the fourth board layer 304, the fifth board layer 305, the sixth board layer 306, and the seventh board layer 307. In general, if the other end of the first sub-return hole group 530 is connected to the GND of the third plate layer 303, the first sub-return hole group 530 penetrates the GND of the plate layer between the top layer and the third plate layer 303, that is, the first sub-return hole group 530 connects the GND of the second plate layer 302 and the third plate layer 303. Alternatively, if the other end of the first sub-reflow hole group 530 is connected to GND of the fourth board layer 304, the first sub-reflow hole 531 group 530 penetrates GND of the board layer between the top layer and the fourth board layer 304, that is, the first sub-reflow hole 531 group 530 connects GND of the second board layer 302, the third board layer 303, and the fourth board layer 304.

Fig. 9 is a schematic cross-sectional structure diagram of a circuit board according to an embodiment of the present disclosure. Fig. 9 is a schematic cross-sectional view taken along the line a-a in fig. 8. Referring to fig. 9, in some embodiments of the present application, the other end of the first sub-return-flow hole group 530 is connected to GND of the third plate layer 303, and the first sub-return-flow hole group 530 penetrates GND of the plate layer between the top layer and the third plate layer 303, that is, the first sub-return-flow hole group 530 is connected to GND of the second plate layer 302 and the third plate layer 303. The return path of the signal of the positive signal gold finger 521 portion includes: the first grounding golden finger 511, the first sub-reflow hole group 530, the GND of the second board layer, and the first grounding golden finger 511, the first sub-reflow hole group 530, the GND of the third board layer increase the reflow path and reduce the loss.

In some embodiments of the present application, one end of the first sub-reflow hole group 530 is connected to the first grounding gold finger 511, and the other end may also be connected to the GND of the second board layer. Fig. 10 is another schematic cross-sectional view taken along the line a-a in fig. 8. As shown in fig. 10, a schematic diagram of the first sub-return-hole group 530 connecting only the top layer and the GND of the second board layer is shown. The return path of the signal of the positive signal gold finger 521 portion includes: the top layer first grounding golden finger 511, the first sub-reflow hole group 530 and the GND of the second board layer increase the reflow path and reduce the loss.

The projection of the first sub-return-flow-hole group 530 on the intermediate layer 309 is located at GND of the intermediate layer 309, and the number of return-flow holes in the first sub-return-flow-hole group 530 may be set to be various, such as 1 to 8. The specific number of reflow holes in the first sub-reflow hole group 530 may be set in relation to the reflow holes according to the overall length of the first grounding gold finger 511.

With continued reference to fig. 8, in some embodiments of the present application, the first sub-reflow hole group 530 includes 5 reflow holes, which are sequentially referred to as a first sub-reflow hole 531, a second sub-reflow hole 532, a third sub-reflow hole 533, a fourth sub-reflow hole 534, and a fifth sub-reflow hole 535 from small to large according to the distance from each reflow hole to the end of the first grounded gold finger 511.

In some embodiments of the present application, the first sub-reflow holes 531, the second sub-reflow holes 532, the third sub-reflow holes 533, the fourth sub-reflow holes 534, and the fifth sub-reflow holes 535 may be distributed at equal intervals or may be distributed at unequal intervals in the first grounding gold finger 511. The distance between every two backflow holes is the distance between the central axes of the adjacent backflow holes.

For convenience of manufacturing and providing a finished product yield, the first sub-reflow holes 531, the second sub-reflow holes 532, the third sub-reflow holes 533, the fourth sub-reflow holes 534, and the fifth sub-reflow holes 535 are generally distributed at equal intervals in the first grounding gold finger 511, and the intervals between the first sub-reflow holes 531 and the second sub-reflow holes 532, between the second sub-reflow holes 532 and the third sub-reflow holes 533, between the third sub-reflow holes 533 and the fourth sub-reflow holes 534, and between the fourth sub-reflow holes 534 and the fifth sub-reflow holes 535 are equal to the distances from the first sub-reflow holes 531 to the end of the first grounding gold finger 511, and from the fifth sub-reflow holes 535 to the beginning of the first grounding gold finger 511, so that the appearance of the circuit board 300 is more beautiful, and the signal reflow path is increased. The signal of the positive signal gold finger 521 portion adds an additional signal return path.

Typically, the diameter of the reflow hole should be smaller than the width of the first grounding finger 511, and the shadow of the first grounding finger 511 in the intermediate layer 309 completely covers the reflow hole. For high speed signals, the smaller the diameter of the return holes, the better, while allowing for process capability, typically 6mil holes are used. And metal is arranged on the surface of the backflow hole and used for signal backflow.

In the embodiment of the present application, the reflow holes are buried holes, i.e., the reflow holes do not penetrate through the gold fingers of the top layer and do not penetrate through the GND of the middle layer 309.

In order to reduce the signal return path of the negative signal gold finger 522 portion, in the embodiment of the present application, a second sub-return-current-hole set 540 is disposed on the circuit board 300 and located in the projection area of the second grounding gold finger 512 in the middle layer 309. One end of the second sub-via set 540 is connected to the second grounding gold finger 512, and the other end is connected to the GND of the middle layer 309, for connecting the second grounding gold finger 512 with the ground signal of the middle layer 309.

The signal return path of the negative signal gold finger 522 is changed from the original return flow through the second grounding gold finger 512 to the return flow through the second grounding gold finger 512, the second grounding gold finger 512 and the second sub-return flow hole group 540 to the intermediate layer 309, so that the signal return path is increased, and the loss is reduced.

The distribution of the second sub-return-flow hole group 540 between different board layers may refer to the first sub-return-flow hole group 530, and the other end of the second sub-return-flow hole group 540 is connected to the GND of the intermediate layer 309, that is, the other end of the second sub-return-flow hole group 540 may be connected to the GND of any one or several of the second board layer 302, the third board layer 303, the fourth board layer 304, the fifth board layer 305, the sixth board layer 306, and the seventh board layer 307. In general, if the other end of the second sub-return hole group 540 is connected to GND of the third plate layer 303, the second sub-return hole group 540 penetrates GND of the plate layer between the top layer and the third plate layer 303, that is, the second sub-return hole group 540 is connected to GND of the second plate layer 302 and the third plate layer 303. Alternatively, if the other end of the second sub-reflow hole set 540 is connected to the GND of the fourth board layer 304, the second sub-reflow hole set 540 penetrates the GND of the board layer between the top layer and the fourth board layer 304, that is, the second sub-reflow hole set 540 is connected to the GND of the second board layer 302, the third board layer 303, and the fourth board layer 304.

The projection of the second sub-via hole set 540 on the intermediate layer 309 is located at GND of the intermediate layer 309, and the number of via holes in the second sub-via hole set 540 may be set to be various, such as 1 to 8. The specific number of reflow holes in the second sub-reflow hole set 540 may be set according to the overall length of the second grounding gold finger 512.

In some embodiments of the present application, the second sub-via set 540 includes 5 vias, which are sequentially referred to as a sixth sub-via 541, a seventh sub-via 542, an eighth sub-via 543, a ninth sub-via 544 and a tenth sub-via 545 from small to large according to the distance between each via and the end of the second grounded gold finger 512.

In some embodiments of the present disclosure, the sixth sub-reflow hole 541, the seventh sub-reflow hole 542, the eighth sub-reflow hole 543, the ninth sub-reflow hole 544 and the tenth sub-reflow hole 545 may be distributed in the second grounding gold finger 512 at equal intervals or may not be distributed at equal intervals. The distance between every two backflow holes is the distance between the central axes of the adjacent backflow holes.

For convenience of manufacturing and providing a finished product yield, the sixth sub-reflow hole 541, the seventh sub-reflow hole 542, the eighth sub-reflow hole 543, the ninth sub-reflow hole 544 and the tenth sub-reflow hole 545 are generally distributed at equal intervals in the second grounding gold finger 512, and the intervals between the sixth sub-reflow hole 541 and the seventh sub-reflow hole 542, the seventh sub-reflow hole 542 and the eighth sub-reflow hole 543, the eighth sub-reflow hole 543 and the ninth sub-reflow hole 544, and the ninth sub-reflow hole 544 and the tenth sub-reflow hole 545 are equal to the distances from the sixth sub-reflow hole 541541 to the end of the second grounding gold finger 512, and from the tenth sub-reflow hole 545 to the beginning of the second grounding gold finger 512, so that the circuit board 300 has a more beautiful appearance and a signal reflow path is increased. The signal of the negative signal gold finger 522 portion adds a signal return path.

Similarly, for the high-speed signal golden finger arranged on the bottom layer, a bottom surface return hole group can be arranged, a signal return path is added, and the arrangement of the bottom layer return hole group refers to the arrangement of the first return hole group and the second return hole group. A bottom-layer grounding gold finger is arranged near the bottom-layer signal gold finger, a bottom-layer return hole group is arranged in the projection of the middle layer 309 of the bottom-layer grounding gold finger, one end of the bottom-layer grounding gold finger is connected with the bottom-layer grounding gold finger, and the other end of the bottom-layer grounding gold finger is connected with the GND of the middle layer 309.

The application discloses optical module includes: the upper shell and the lower shell cover a wrapped cavity formed by covering, and a circuit board arranged in the wrapped cavity. The circuit board includes: a top layer and a middle layer. The top layer is provided with a signal golden finger and a grounding golden finger, wherein the signal golden finger is used for transmitting signals, and the grounding golden finger is arranged on one side of the signal golden finger and used for backflow of the signals in the signal golden finger. The circuit board is internally provided with a buried hole which is positioned in the projection area of the grounding golden finger, one end of the buried hole is connected with the grounding golden finger, and the other end of the buried hole is connected with the grounding wire of the middle layer. This application is through setting up the buried hole below the ground connection golden finger, connects the earth connection of top layer and intermediate level, increases the ground connection signal backflow route of ground connection golden finger to buried hole to intermediate level, reduces high frequency loss, is favorable to improving high frequency.

Claims (10)

1. A light module, comprising: an upper housing;

the lower shell is covered with the lower shell to form a wrapping cavity;

the circuit board is arranged in the packaging cavity and comprises a top layer and a middle layer;

one end of top layer is equipped with the golden finger, include:

one end of the signal golden finger is connected with the functional chip;

the grounding golden finger is arranged on one side of the signal golden finger and is used for the backflow of signals in the signal golden finger;

the circuit board is internally provided with a buried hole which is positioned in the projection area of the grounding golden finger, one end of the buried hole is connected with the grounding golden finger, and the other end of the buried hole is connected with the grounding wire of the middle layer.

2. The optical module of claim 1, wherein the signal gold finger comprises: a positive signal golden finger and a negative signal golden finger;

the grounding golden finger comprises: a first grounding golden finger and a second grounding golden finger;

the positive signal golden finger and the negative signal golden finger are arranged between the first grounding golden finger and the second grounding golden finger.

3. The light module of claim 2, wherein the buried via comprises: a first sub-return hole group and a second sub-return hole group;

and the projections of the first sub-backflow hole group and the second sub-backflow hole group on the middle layer are positioned on the grounding wire of the middle layer.

4. The optical module according to claim 3, wherein the number of buried holes in the first sub return hole group and the second sub return hole group is plural.

5. The optical module of claim 3, wherein the number of buried holes of the first sub return flow hole group is 5.

6. The optical module according to claim 5, wherein the projections of the buried holes of the first sub-return hole group in the first grounded gold finger are distributed at equal intervals.

7. The optical module of claim 1, wherein the buried via has a diameter of 3-8 mils.

8. The light module of claim 1, wherein the intermediate layer comprises: a second slab layer and a third slab layer, the second slab layer disposed between the top layer and the third slab layer; one end of the buried hole is connected with the grounding golden finger, the other end of the buried hole is connected with the grounding wire of the third plate layer, and the buried hole is connected with the grounding wire of the second plate layer.

9. The light module of claim 1, wherein the intermediate layer comprises: a second ply; one end of the buried hole is connected with the grounding golden finger, and the other end of the buried hole is connected with the grounding wire of the second plate layer.

10. The optical module of claim 1, wherein a distance between an end of the ground gold finger and an end edge of the circuit board is smaller than a distance between an end of the signal gold finger and an end edge of the circuit board.

Images