Learning notes of Lichuang EDA: Copper laying dead zone? isolated island? Dead copper?

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When laying copper, there was a dead copper （ dead zone ） The concept of , This concept is also reflected in the settings , Namely “ Whether to keep the island ”

What is a copper dead zone ？ What is an island ？

isolated shapes： Solitary copper , Also known as isolated island （ In fact, Li Chuang eda The dead zone and dead copper also refer to this ）
It means in PCB Isolated unconnected copper foil in . It is usually produced when laying copper .
The solution is relatively simple . Can be in PCB In the design, it is connected with the copper foil of the same network by manual connection .
You can also play Through hole Mode connected with copper foil of the same network .
Unsolvable orphan copper , Just delete it .

“ Isolated island ” The word for PCB For designers , Familiar with . This refers to when laying copper , There is no signal in it , To the ground , Copper laying for power connection . There are also people called. “ Dead copper ”“ Broken copper ” As shown in the figure below

I drew some pictures to talk about my experience , Novice , Bosses do not spray ：

In this picture ,p1 It's a 2p Pin for , Used to import external vcc and gnd,led1 It's a led The lamp , It needs one foot to connect vcc, One foot gnd To work properly , For the sake of illustration , I deliberately drew a loop here gnd Surrounded , In fact, there are various reasons for the formation of isolated islands , It's not as simple and rough as me .

I drew a copper frame outside and wrapped it , It's like this

The one you think is wrapped up in the middle is called an island ？
incorrect , Although it is similar to the copper shop outside -gnd to be isolated , But it still has a network , Its network name is gnd.

and gnd Your network is incomplete , So the Internet flyer will always remind you .

This is the time , Whether you choose to keep the island or not , There will be no change in this diagram , Because it's not an island at all .

To solve this problem, you can punch a hole and run the line on the bottom floor .

Look at the picture below

The difference between this figure and the previous figure is led I changed my direction , If you lay copper and frame it all at this time （ Choose to keep the island ） It becomes the following , A large area outside is covered with copper handles led1 Of gnd And socket gnd It's connected .

This time was vcc The part surrounded is called an island , It doesn't belong to any network , If the reconstruction shop copper , Then choose not to keep the island, as shown in the figure below

Oh , by the way , Whether the copper laying is visible or not, click the blank space and then modify the properties .

The properties of copper laying can only be modified by clicking the border of copper laying .

The above is my personal understanding of copper island , I hope it can help novices .

There's something on the Internet about whether to remove the dead zone （ Isolated island ） The discussion of the , I think this answer is better , I put it under it ：

Some people say we should get rid of , The reason is probably ：
Can cause EMI problem

Enhance the anti-jamming ability

Dead copper is useless

But others say it should be kept , The reason is probably ：

Sometimes large blank areas don't look good

Increase the mechanical properties of the board , Avoid uneven bending

that , Who is right and who is wrong ？

First of all , Let's not die （ Isolated island ）, Because this island forms an antenna effect here , If the radiation intensity of the surrounding wiring is high , Will increase the intensity of the surrounding radiation ; And it will form the acceptance effect of the antenna , It will introduce electromagnetic interference to the surrounding wiring .

second , We can delete some small isolated islands . If we want to keep the copper coating , The isolated island should be connected with GND Good connection , Form a shield .

Third , At high frequencies , The distributed capacitance of the wiring on the printed circuit board will work , When the length is greater than the corresponding wavelength of noise frequency 1/20 when , There will be an antenna effect , The noise will be emitted through the wiring . If in PCB If there is copper clad with poor grounding in , Copper cladding has become a tool for spreading noise .

therefore , In high frequency circuits , Never think of , Ground the ground wire somewhere , This is it. “ Ground wire ”, Must be less than λ/20 The distance between , Punch holes in the wiring , With the ground plane of the multilayer board “ Good grounding ”. If the copper coating is handled properly , Copper cladding not only increases the current , It also plays a dual role of shielding interference .

Fourth , Through a hole in the ground , Keep the copper coating of the island , Not only can it play the role of shielding interference , It can also prevent PCB deformation .