Hermetically sealed enclosure and method for designing the weld connection for such an enclosure

A method for designing a laser weld between a base substrate and a cover substrate of an enclosure, wherein the base substrate has a functional region and the cover substrate, which is in contact with the base substrate, covers the functional region, the method comprising:

• directly connecting the base substrate and the cover substrate to one another hermetically tightly via at least one laser bonding line so that the functional region is hermetically enclosed inside the resulting enclosure, wherein a minimum shear force Fmin, which the laser weld is intended to withstand, is specified for the connection between the cover substrate and the base substrate, and in that a sum of lengths Lges of all laser bonding lines is selected to be greater than a required minimum length Lmin of the length of all laser bonding lines, Lmin being determined by dividing the specified minimum shear force Fmin by an empirically determined force per unit laser bonding line length P so Lmin=Fmin/P, and in that a contact area width B, measured in a plane of a front face of the base substrate, which faces toward the cover substrate, as a shortest route between the functional region and an exterior of the enclosure, is selected so that a ratio J=Ai/Aw formed from a contact area Ai, on which the base substrate and the cover substrate can touch, and a laser bonding area Aw spanned by the at least one laser bonding line with a width w on the front face of the base substrate, which faces toward the cover substrate, lies in a range of from 1 to 10.

A sensor unit and/or a medical implant, comprising:

• an enclosure comprising:
• a base substrate having a functional region;
• and
• a cover substrate which is in contact with the base substrate and covers the functional region, wherein the base substrate and the cover substrate are directly connected hermetically tightly to one another via at least one laser bonding line, and wherein the functional region is hermetically enclosed inside the resulting enclosure, wherein a ratio J=Ai/Aw formed from a contact area Ai, on which the base substrate and the cover substrate can touch, and a laser bonding area Aw spanned by the at least one laser bonding line with a width w on a surface of an interface between the base substrate and the cover substrate lies in a range of from 1 to 10, and a contact area width B, measured in a plane of a front face of the base substrate, which faces toward the cover substrate, as a shortest route between the functional region and an exterior of the enclosure, lying in a range of 100 μm to 1000 μm.