Electronic circuit laid flat and corresponding three-dimensional electronic circuit

1. A flat electronic circuit, comprising a set of electronic boards intended to support components and linked together by joining elements, wherein the joining elements comprise curved flexible printed circuits linking two ends of two electronic boards of the set of electronic boards, the two electronic boards being arranged side by side, wherein the flat electronic circuit comprises two parallel rectilinear branches linked together by their ends by two curved flexible printed circuits so as to form a closed flat electronic circuit and each parallel rectilinear branch comprises electronic boards linked by a straight flexible printed circuit, the said curved flexible printed circuits being foldable and the straight flexible printed circuits being bendable for erecting the flat electronic circuit into a three-dimensional electronic circuit comprising electronic boards placed opposite one another; wherein said curved flexible printed circuits are foldable along fold lines running at 45° with respect to the rectilinear branches.

2. The electronic circuit according to claim 1 , wherein the curved flexible printed circuits comprise a first part joined to one of the two electronic boards bound to the flexible circuit, a second part joined to the other electronic board and a middle part situated between the first part and the second part and intended to define with the first part a first fold line and with the second part a second fold line.

3. The electronic circuit according to claim 2 , wherein the first part and the second part of each curved flexible printed circuit have the same shape and the same dimensions, the fold lines delimiting a rectangular zone intended to be joined by one of its sides to an electronic board, and a pentagonal zone comprising a first side common to the large side of the rectangular zone, a second side orthogonal to the first, a third side, a fourth side joined to the middle part and orthogonal to the third, and a fifth side parallel to the third.

4. The electronic circuit according to claim 2 , in which the middle part is a hexagon, comprising a first side common to the fourth side of the pentagon-shaped part of the first part, a second side, a third side common to the fourth side of the pentagon-shaped part of the second part, a fourth side, a fifth side parallel to the second side and a sixth side.

5. The electronic circuit according to claim 1 , wherein electronic components are soldered on one of the faces of the electronic circuit.

6. A three-dimensional electronic circuit obtained on the basis of a flat electronic circuit comprising a set of electronic boards intended to support components and linked together by joining elements, wherein the joining elements comprise folded curved flexible printed circuits linking two ends of two electronic boards side by side so that the electronic circuit comprises electronic boards placed opposite one another, wherein the flat electronic circuit comprises two parallel rectilinear branches linked together by their ends by two curved flexible printed circuits so as to form a closed flat electronic circuit and each parallel rectilinear branches comprising electronic boards linked by a straight flexible printed circuit, and wherein said three-dimensional electronic circuit being formed by folding the curved flexible printed circuits and bending the straight flexible printed circuits, so that the electronic boards of the three-dimensional electronic circuit are oriented in four different planes; wherein said curved flexible printed circuits are foldable along fold lines running at 45° with respect to the rectilinear branches.

7. The three-dimensional electronic circuit according to claim 6 , wherein the components supported by the electronic boards comprise infrared sensors and light-emitting diodes.

8. The three-dimensional electronic circuit according to claim 6 , wherein the three-dimensional electronic circuit is intended to be integrated into a rectangular frame intended to be incorporated into a touchscreen.

9. The electronic circuit according to claim 1 , wherein the two parallel rectilinear branches comprise: a first rectilinear branch that comprises a first and a second electronic board linked together by a first straight flexible printed circuit; and a second rectilinear branch that comprises a third and a fourth electronic board linked together by a second straight flexible printed circuit and wherein a first curved flexible circuit is arranged so that its ends bound respectively to the first and fourth electronic boards and a second curved flexible circuit is arranged so that its ends bound respectively to the second and third electronic board.