BACKGROUND ART Electrical and electronic circuit specialists are required more and more often to design circuits that are as small and compact as possible. This is caused by the limitations in space where a given circuit is to be installed, by constant increase in circuit complexity and by the fact that components in compact circuits are connected by short paths, which results in decreased size of parasitic components.

One of the methods for decreasing the dimensions of electronic circuits is the use of integrated circuits. When a need for discrete elements arises, small Surface Mounted Devices (SMD) can be used. In many cases, however, the space allotted to an electronic circuit requires further decrease in that circuit size.

AIM OF THE INVENTION The invention seeks to provide a printed circuit board with electronic components to be mounted in a limited space.

DISCLOSURE OF THE INVENTION The object of the invention is a printed circuit board and electronic elements for mounting in that printed circuit board. The electronic elements have surfaces allowing electrical connection with conducting layers of the printed circuit of the board. The printed circuit board has at least one hole, which is in principle perpendicular to the surface of the printed circuit board, and which ends at the conducting layers of the printed circuit of the board. In the hole of the board at least one electronic element is mounted, having, at its terminals, surfaces allowing electrical connection with the conducting layers of the printed circuit of the board through a joining substance, which creates an electrical connection of the, electronic element and the printed circuit of the board.

The printed circuit board can comprise several isolating layers and each layer has its own printed circuit.

The printed circuit board can comprise several isolating layers between which conducting layers are situated.

The hole of the printed circuit board can extend through several isolating layers.

The cross section of the hole can have the shape of an arbitrary plain figure.

The cross section of the electronic element can have the shape of an arbitrary plain figure.

At least one end of the hole can be at least partially covered by a conducting layer of the board.

At least one end of the hole can be at least partially covered by a conducting layer situated between isolating layers of the board.

The conducting surfaces of the electronic element can be situated at its terminals.

The electronic element can be mounted in an isolating casing placed in the hole.

The isolating casing can be made of a gel substance or can be an isolating sleeve.

The electronic element can have a part whose diameter is larger than the diameter of the hole in which the electronic element is mounted.

The object of the invention is also a method for mounting electronic elements in a printed circuit board, in which a hole is made. The hole extends in principle perpendicularly to the surface of the board, in which at least one electronic element is mounted that has surfaces at its terminals that allow electrical connection and which is connected through a substance conducting electrical current with the printed circuit of the board.

BRIEF DESCRIPTION OF DRAWINGS The object of this invention is shown in implementation examples in the enclosed drawings, in which: Fig. 1 shows a printed circuit board along with cylindrical electronic components; Fig. 2 shows a cross section of a printed circuit board with an electronic element inside; Fig. 3 shows a cross section of a multi-layered printed circuit board with an electronic component placed inside the isolating layer ; Figs. 4,5, and 6 show various methods for mounting electronic components; and Figs. 7,8, and 9 show various shapes of electronic components.

BEST MODE FOR CARRYING OUT THE INVENTION Fig. 1 shows a printed circuit board and electronic elements or components that are mounted therein. On an isolating layer 1 of this board there is a bottom conducting layer 2, which consists of conducting paths, and a top conducting layer 3. Both the conducting layers 2 and 3 can be made by sputtering, by etching the conducting material or by using conducting foils, attached by arbitrary method, for instance by gluing. In the hole or the opening 5, made in the conducting layers 2,3, and in the isolating layer 1, an electronic component 4-connected electrically with both conducting layers 2 and 3-is placed. The electronic component 4 can be connected with conducting layers 2 and 3 by soldering, welding or by the use of an elastic conducting joining substance. The connection can be direct or through intermediate elements, for instance metal connector terminals attached or otherwise placed on the electronic component terminals. Another electronic component 8 is placed in a partial opening 9, made only in the isolating layer 1. The electronic component 8 is connected with the top conducting layer 3 through a binding material 10 and with the path 6 of the bottom conducting layer 2 through a binding material 7. Before the conducting layers 2 and 3 are applied, the electronic element 8 is placed in the opening 9. After their application, it is soldered to them, for instance by point heating. Electronic components 4 and 8 are cylindrically shaped, as are the openings where they are placed. Diameters of the openings are matched to the diameters of electronic components.

Fig. 2 shows a lateral cross section of the printed circuit board with an electronic component 14 connected, by its terminals, through intermediate elements 15 and 16, to a top conducting path 13 through a binding material 18, and to the bottom conducting path 12 through a binding material 19. The top conducting path 13 and the bottom conducting path 12 are separated by an isolating layer 11. The opening made in the top conducting layer 13 has bevel edges 17 which allow easier placement of the electronic component 14 in the opening, and its easier soldering. The height of the electronic component 14, including the intermediate elements 15 and 16, is slightly greater than the sum of the thickness of the isolating layer 11, the top conducting path 13, and the bottom conducting path 12.

Fig. 3 shows a cross section of a multi-layered board with printed circuits. It is made up of several isolating layers 21,32, and 33 as well as conducting layers 22, 23, and 31, placed between the isolating layers 21,32, and 33, and on the outside of the isolating layers 21, and 32. An electronic component 24 is placed inside an opening made in the first bottom layer 32 and in the second bottom layer 33 of the board. The electronic component 24 has a bottom intermediate element 27 on one of its terminals, which improves the contact between the electronic component 24, a binding material 26, and the bottom conducting layer 22. The electronic component 24 has at its other terminal a top intermediate element 28, which improves the contact between the electronic component 24, a binding material 25, and the top conducting layer 23. The electronic component 24 can also be connected directly, without the use of intermediate elements. The height of the electronic component 24 including the intermediate elements 27,28-as shown in Fig. 3-is smaller than the sum of the thickness of the bottom layers 32 and 33 of the board. The binding material 25 replaces the missing part of the electronic component 24, filling the opening 20 up to the top surface of the conducting layer 23. The electronic element 24 is placed in an isolating casing 29, which can be either an isolating tube or can be made of gel. Apart from isolating the electronic component 24 from other conducting layers, the isolating casing 29 also facilitates its placement in the opening 20 during mounting.

The opening 30, made in the top layer 21 of the board, along with the conducting layer 31, allows heating up the binding material 25 in a case when the electronic element is mounted after the conducting layers have been applied.

Fig. 4 shows a board with an isolating layer 71, a bottom conducting layer 72, and a top conducting layer 73. An electronic component 74 is placed inside an opening made only in the isolating layer 71. The electronic element 74 is connected with the bottom conducting layer 72 through a binding material or another conducting contact material 76 and with the top conducting layer 73 through a binding material or another conducting contact material 75, for instance a conducting paste. When mounting the electronic element 74 in the board, the opening is first made in the isolating layer 71, into which the electronic component 74 is placed, together with the binding or conducting contact material 76 and the binding or conducting contact material 75. In the end, the bottom conducting layer 72 and the top conducting layer 73 are applied onto the isolating layer 71. The connection of the electronic element 74 with the bottom conducting layer 72 and the top conducting layer 73 is self- created when a conducting contact material is used. The connection may be also created by point heating of the conducting layers in the place of their contact with the binding material.

Fig. 5 shows a board with an opening made in an isolating layer 81 and a top conducting layer 83. An electronic component 84 is connected, by its bottom terminal, with a bottom conducting layer 82 via a binding material 86.

When mounting, the top conducting layer 83 is first applied onto the isolating layer 81. Next, the opening is made. After applying the bottom conducting layer 82, the electronic component 84 is placed in the opening and connected to the bottom conducting layer 82 through the binding material 86, and to the top conducting layer 83 through a binding material 85. The electronic component can also be connected through intermediate elements.

Fig. 6 shows a mushroom-shaped electronic component 94. A top part 95 of the electronic component 94 has a diameter greater than an opening 97 made in an isolating layer 91, a bottom conducting layer 92, and a top conducting layer 93. When mounting, the top part 95 of the electronic element 94 rests on the top conducting layer 93, in this way facilitating its connection with the conducting layers using binding agents 98 and 99.

Figs. 7,8, and 9 show various shapes of openings and of electronic components that are placed therein. Fig. 7 shows an electronic component 34 of a shape of a right prism with intermediate elements 37, 38, placed in a cylindrical opening 35, which is shown as an outline. Fig. 9, in turn, shows a cylindrical electronic component 44 with intermediate elements 47 and 48, placed in an opening 45 of a shape of a right prism, which is shown as an outline. Fig. 8 shows an electronic component 54 of a shape of a right prism with intermediate elements 57 and 58, placed in an opening 50, which is shaped as a right prism with a triangular base. The electronic components and openings can be of any shape, not necessarily those shown in Fig. 7,8, and 9.