Circuit board system with mechanical protection

Abstract

A circuit board system including mechanical protection of electrical components includes a circuit board ( 101 ) furnished with electrical components ( 103 - 111 ) and a protection element ( 102 ) attached to areas of the circuit board which are free from the electrical components. The protection element has thickness in the direction perpendicular to the circuit board and it is shaped to leave the electrical components unscreened in the direction perpendicular to the circuit board. Thus, the protection element constitutes barriers protecting the electrical components but still allows the electrical components to be accessed from the direction perpendicular to the circuit board for example in a flying probe testing. The body of the protection element can be made of same material as the electrically insulating body of the circuit board. Thus, the thermal expansion co-efficient of the protection element can be substantially the same as that of the circuit board.

What is claimed is: 
     
         1 . A circuit board system comprising:
 a circuit board furnished with electrical components on a surface of the circuit board, and   at least one protection element attached to areas of the surface of the circuit board which are free from the electrical components, the protection element having thickness in a direction perpendicular to the circuit board and width and length in directions parallel with the circuit board, the protection element being shaped to leave the electrical components unscreened in the direction perpendicular to the circuit board and the width of the protection element being greater than the thickness of the protection element,   
       wherein the protection element comprises electrically conductive parts connected to electrically conductive parts of the circuit board and providing at least one galvanic connection between a first functional entity of the circuit board system and a second functional entity of the circuit board system. 
     
     
         2 . A circuit board system according to  claim 1 , wherein the protection element is attached to the circuit board with at least one of the following: glue, screws, soldering, press-fit pins. 
     
     
         3 . A circuit board system according to  claim 1 , wherein the first functional entity of the circuit board system is a power supply converter of the circuit board system and the second functional entity of the circuit board system is a signal processing part of the circuit board system. 
     
     
         4 . A circuit board system according to  claim 3 , wherein the signal processing part of the circuit board system comprises a processing system for supporting at least one of the following data transfer protocols: Internet Protocol IP, Ethernet protocol, MultiProtocol Label Switching MPLS protocol, Asynchronous Transfer Mode “ATM”. 
     
     
         5 . A circuit board system according to  claim 1 , wherein the electrically conductive parts of the circuit board comprise electrically conductive linings of holes of the circuit board, and the electrically conductive parts of the protection element comprise electrically conductive pins pushed to the holes of the circuit board and an electrical conductor between the pins. 
     
     
         6 . A circuit board system according to  claim 5 , wherein the pins of the protection element are press-fit pins providing friction fits with the electrically conductive linings of the holes of the circuit board. 
     
     
         7 . A circuit board system according to  claim 5 , wherein the pins of the protection element are soldered to the electrically conductive linings of the holes of the circuit board. 
     
     
         8 . A circuit board system according to  claim 1 , wherein the electrically conductive parts of the protection element comprise electrically conductive linings of holes of the protection element and an electrical conductor between the electrically conductive linings, and the electrically conductive parts of the circuit board comprise electrically conductive pins pushed to the holes of the protection element. 
     
     
         9 . A circuit board system according to  claim 1 , wherein the protection element has a netlike structure so that the protection element comprises openings for the electrical components and constitutes barriers between the electrical components. 
     
     
         10 . A circuit board system according to  claim 1 , wherein the protection element has a loop-shaped structure surrounding at least one of the electrical components. 
     
     
         11 . A circuit board system according to  claim 1 , wherein the circuit board comprises first soldering pads on the surface of the circuit board, and the protection element comprises corresponding second soldering pads on a surface of the protection element, and there are solder joints between the first soldering pads of the circuit board and the second soldering pads of the protection element. 
     
     
         12 . A circuit board system according to  claim 1 , wherein a body of the protection element is made of same material as an electrically insulating body of the circuit board so as to make the thermal expansion coefficient of the protection element to be substantially same as that of the circuit board. 
     
     
         13 . A circuit board system according to  claim 1 , wherein the protection element comprises rubber so as to make the protection element flexible. 
     
     
         14 . A method for manufacturing a circuit board system, the method comprising:
 furnishing a circuit board with electrical components onto a surface of the circuit board, and   attaching at least one protection element to areas of the surface of the circuit board which are free from the electrical components, the protection element having thickness in a direction perpendicular to the circuit board and width and length in directions parallel with the circuit board, the protection element being shaped to leave the electrical components unscreened in the direction perpendicular to the circuit board and the width of the protection element being greater than the thickness of the protection element,   
       wherein the attaching the at least one protection element to the areas of the surface of the circuit board comprises providing, with the aid of the protection element, at least one galvanic connection between first and second functional entities of the circuit board system, the first functional entity comprising first ones of the electrical components and the second functional entity comprising second ones of the electrical components. 
     
     
         15 . A method according to  claim 14 , wherein, the circuit board and the at least one protection element comprise soldering pads, and the at least one protection element is attached to the circuit board in a same soldering process in which those of the electrical components that are surface mounted devices “SMD” are attached to the circuit board. 
     
     
         16 . A method according to  claim 14 , wherein the method comprises, after the furnishing of the circuit board with the electrical components and prior to attaching the at least one protection element to the areas of the surface of the circuit board:
 testing the first functional entity, and   testing the second functional entity, the first and second functional entities being tested separately from each other, and   
       after the attaching the at least one protection element to the areas of the surface of the circuit board:
 testing functionality of the circuit board system so that the first and second functional entities are co-operating with each other via the at least one galvanic connection during the testing of the functionality. 
 
     
     
         17 . A method according to  claim 14 , wherein the first functional entity of the circuit board system is a power supply converter of the circuit board system and the second functional entity of the circuit board system is a signal processing part of the circuit board system.