A tube (2) of a heat exchanger (1) is intended to allow an exchange of heat between a first fluid and a second fluid flowing in contact with the tube (2). The tube (2) comprises an upper plate (22) and a lower plate (21) positioned facing one another and defining an internal space (25) in the tube (2) in which the first fluid is able to circulate. Each of the plates (21, 22) comprises a bottom (23) and at least one edge (24). The plates (21, 22) are in contact with one another at the edge (24). The tube (2) comprises a deflection screen (30) secured to the edge (24), with the deflection screen (30) comprising a first wall (31) extending transversely to the bottoms (23) and arranged to deflect the second fluid toward the bottoms (23). The invention also relates to a bundle of such tubes and to a heat exchanger comprising such a bundle, and to a method for producing a heat exchanger tube plate.