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A flexible circuit board and corresponding optical module

A technology of flexible circuit boards and optical modules, applied in the field of optical communications, can solve problems affecting wiring impedance matching, high-speed signal mismatch, shortening of solder resistance sections, etc., to reduce manufacturing difficulty and processing costs, and realize high-speed signal matching Transmission, avoiding the effect of impedance mutation

Active Publication Date: 2021-10-29
WUHAN ACCELINK TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

like figure 1 and figure 2 As shown, the connection line connecting the pad and the signal transmission line is connected to the pad and the signal transmission line through a straight line. The pad and the signal transmission line use the GND of the pad surface as the reference GND, and the solder resistance section where the connection line is located has no Refer to GND, and the length of the solder mask section is determined by the processing technology. The length is generally greater than 0.15mm, which will seriously affect the impedance matching of the traces. Since the solder mask section does not have a GND reference ground, it has a large parasitic inductance. The equivalent impedance is between 60Ω and 80Ω, and there is a problem of high-speed signal mismatch
For the impedance mismatch between the pad and the transmission line, the method of improving the processing accuracy and reducing the solder resist section is generally adopted. However, with the improvement of the processing accuracy, the product cost also increases, and there is a short solder resist section, and electron migration Risk of short-circuit failure of the product

Method used

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  • A flexible circuit board and corresponding optical module
  • A flexible circuit board and corresponding optical module
  • A flexible circuit board and corresponding optical module

Examples

Experimental program
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Embodiment 1

[0034] At present, the high-speed signal transmission network has a trace width difference jump at the connection between the pad and the signal line, and the impedance at the jump is discontinuous. The excited electromagnetic radiation not only weakens the effective signal transmission, but also brings parasitic crosstalk. To solve this problem, This embodiment provides a flexible circuit board.

[0035] refer to image 3 , the embodiment of the present invention provides a flexible circuit board, the flexible circuit board includes: a signal transmission line 1, an impedance matching line 2 and a pad 3, and the impedance matching line 2 connects the signal transmission line 1 and the pad 3 .

[0036] Wherein, the width corresponding to the signal transmission line 1 is smaller than the width corresponding to the pad 3, the impedance matching line 2 changes gradually, and the width of the impedance matching line 2 is along the direction close to the pad 3 Gradually increase...

Embodiment 2

[0063] Based on the description of the foregoing embodiments, a set of specific parameters is used for supporting explanations. Here, a single-ended 50-ohm impedance line is used as an example to transmit a 25Gbit / s high-speed signal. The thickness of the substrate is 0.05mm±0.01mm, the dielectric constant of the substrate is 3.2±0.05, and the loss tangent angle is 0.002±0.001. The width of the pad is 0.25mm±0.01mm (that is, a=0.25mm±0.01mm), the distance between the pad and the signal transmission line is 0.2mm±0.01mm (that is, a=0.2mm±0.01mm), and the thickness of the cover film is 0.025mm± 0.01mm, the dielectric constant of the covering film is 3.5±0.05.

[0064] Combining the above parameters, according to the formula three of the embodiment 1, the line width of the signal transmission line is calculated to be 0.1mm (that is, w=0.1mm), and a=0.25mm±0.01mm, w=0.1mm and a=0.2mm± Substitute 0.01mm into formula 1 and formula 2 to obtain the first gradient curve and the second...

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Abstract

The invention discloses a flexible circuit board and a corresponding optical module. The flexible circuit board includes: a signal transmission line, an impedance matching line and a pad, and the impedance matching line connects the signal transmission line and the pad; wherein, the The width corresponding to the signal transmission line is smaller than the width corresponding to the pad, the impedance matching line changes gradually, and the width of the impedance matching line gradually increases in a direction approaching the pad. The flexible circuit board provided by the present invention connects the pad and the signal transmission line through an impedance matching line, wherein the impedance matching line changes gradually, avoiding the sudden change in impedance between the signal transmission line and the pad, and realizing high-speed signal transmission in the solder resistance section. Match transmission. At the same time, the precision requirements for manufacturing and processing are relatively low, which reduces the manufacturing difficulty and processing cost.

Description

technical field [0001] The invention belongs to the technical field of optical communication, and more specifically relates to a flexible circuit board and a corresponding optical module. Background technique [0002] Since the advent of Flexible Printed Circuit (FPC), it has been widely used in electronics, electrical appliances, automobiles and medical products due to its advantages of thinness, flexibility, small footprint and high degree of bending freedom. Especially in the field of optical communication, under the requirements of miniaturization, high integration and high speed of optoelectronic devices and optoelectronic modules, FPC is used more and more, and higher requirements are put forward for the high-speed signal transmission characteristics and high reliability of FPC. requirements. [0003] At present, the conventional high-speed FPC has the problem of high-speed signal mismatch between the pad and the solder resistance section of the high-speed signal tran...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05K1/02G02B6/42
CPCG02B6/4279G02B6/4281H05K1/0242H05K1/025H05K2201/0784
Inventor 吴杨张玉安
Owner WUHAN ACCELINK TECH CO LTD
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