The Printed Circuit Board is the base of any electronic product such as computer, cell phone and military equipment. Invented more than 100 years ago, this tiny device heralded a huge leap in the development of electronic equipment. In Russia one of the largest manufacturers of modern Printed Circuit Boards is Concern Radioelectronic Technologies (KRET)
What is a Printed Circuit Board, and why is it called "printed"?
A BIT OF HISTORY
It is believed that the prototype for all kinds of Printed Circuit Boards was created by German engineer Albert Hanson. At the beginning of the last century, he proposed to form the Printed Circuit Board pattern on the copper foil by cutting or stamping. Drawing elements were glued to a dielectric which was a type of paraffin paper.
Thus, the birth year of the Printed Circuit Board is considered to be 1902, when Hanson filed his application with the patent office.
For more than a century the design and manufacturing process of Printed Circuit Boards have continuously improved. A large number of inventors had a hand in the evolution of the Printed Circuit Board, including the world-renowned Thomas Edison. At his time he proposed forming a conductive pattern by means of an adhesive material containing graphite or bronze powders.
And even though Edison never used the term "Printed Circuit Board", many of his ideas have been applied to creation of Printed Circuit Boards, also nowadays.
The first Printed Circuit Boards created in the 1920s, were made of materials such as bakelite, masonite, layered cardboard, and even thin wooden boards. Holes were drilled into the material and then
"wires" consisting of flat brass were screwed onto the board. Sometimes even small nuts and bolts were used. Such Printed Circuit Boards were used in the first radio and gramophones.
WHY IS IT "PRINTED"?
The present form of the Printed Circuit Board grew out of the printing industry. It owes its name to printing industry: “printed circuit board” is derived from the term “printing plate”.
Therefore, the true founder of the Printed Circuit Board is the Austrian engineer Paul Eisler, who first drew the conclusion that printing technologies can be used for mass production of Printed Circuit Boards.
During the Second World War mass production technology of Printed Circuit Boards were very popular, especially for radio equipment of military use, as well as aviation. Since the mid 1950s, the Printed Circuit Board has become the backbone of the entire consumer electronics industry.
In the USSR one of the first such developments occurred in 1953, in the form of the “traffic” radio which was made as a small suitcase and placed within a Printed Circuit Board. Of course, in comparison with the modern one, the Printed Circuit Board was very primitive: a few wide conductors (4-5 mm) with serrated edges located on both sides of the board, connected through plated holes. In 1954 with the use of Printed Circuit Boards the production of Soviet Television “Start” began.
Circuit Boards today are virtually beyond competition as the base of electronic equipment, a part of computers, cell phones and military equipment.
FROM THE LINE TO THE PLANE
What are Printed Circuit Boards?
In short it is the design of electrical wiring on an insulating base. Thus, its main elements are the foundation (substrate) and conductors.
Electronic components on Circuit Boards are often connected by soldering. These elements are necessary and sufficient to ensure that the Printed Circuit Board is a Printed Circuit Board.
By the way, the most distant predecessor of Printed Circuit Boards can be considered to be an ordinary wire which is often insulated. Thus, in development of radio, one can say, a transition from the line to the plane happened.
A Single-sided Printed Circuit Board is a plate, of which, one side has conductors made through printing methods. On double-sided Printed Circuit Boards conductors are on the underside of the plate.
The transition from one-sided to a two-sided Printed Circuit Board was the first step on the way from the plane to the volume. The final transition to volume occurred in 1961, with the introduction of multilayer Printed Circuit Boards.
For example, today, the KRET produces multilayer Printed Circuit Boards with up to 25 layers.
These boards help enable first of all miniaturised electronics. The advantage of saving space was quickly applied by aerospace technologies, aviation, computers, as well as missiles and weapons.
TRANSITION TO THE MICRO-LEVEL
The increasing miniaturisation of electronic devices demanded the transition of Printed Circuit Boards.to micro-level.
While the width of the first Printed Circuit Boards, wires, and gaps between the conductors were measured in millimetres, the development of electronic technology required the creation of a Printed Circuit Board with the size of the elements measured by tenths of a millimetre. In modern electronic equipment such Printed Circuit Boards have become common.
Today, KRET enterprises have produced Printed Circuit Boards with reproduction accuracy of 2 microns and thickness of the substrate boards of 0.25 - 1 mm. The reliability of internal connections of the multilayer boards is controlled through the use of X-ray equipment.
The development of such areas as nanotechnology makes the most unrealistic forecasts regarding the development of the electronic database very real. This entails not just micro- but even nano-miniaturisation of Printed Circuit Boards. Even today, some elements of Printed Circuit Boards may be measured in nanometres.
"PRINTED CIRCUIT BOARD" INNOVATION
For most people the Printed Circuit Board is nothing more than just a rigid plate. Indeed, the rigid Circuit Board is the most popular product used in electronics, but today flexible Printed Circuit Boards are extremely popular.
In Russia, one of the largest manufacturers of such Circuit Boards is the Ryazan State Instrument-Making Enterprise, a subsidiary of KRET.
So, one of the advantages of flexible Printed Circuit Boards is the ability to adjust their shape in accordance with the objects in which they are placed. Flexible boards are made from polyimide material, thus their "substrate" is highly elastic. As a result, there are substantial savings in the internal volume of products.
The latest innovations in production of Printed Circuit Boards also affected materials.
It is well known that as the basis of all Printed Circuit Boards such materials as laminated fibreglass, phenolic paper and ceramics are commonly used. The basis of the Printed Circuit Boards may also be a metal base covered with a dielectric (e.g., anodized aluminium) on top of which the copper foil tracks are applied.
A separate group of materials is aluminium metal Printed Circuit Boards. Here the alumina board is of particular importance. This technology is based on the innovative concept of creating nano-porous material for building multi-level switching layers that combine aluminium and oxidised aluminium in its structure.
Made by using aluminium oxide technology, Printed Circuit Boards and modules provide faster heat dissipation in comparison with similar products produced by "traditional" technology, which increases the reliability and service life.
The main advantage of this technology is the possibility of smelting obsolete Printed Circuit Boards. The produced aluminium can be reused many times over.
KRET has recently started testing sub-assemblies and modules that are constructed and based on innovative alumina boards.
The Concern will assess the feasibility of their use in the production of advanced radar systems for civilian and military purposes, as well as electronic warfare.
Based on materials from the official KRET website
